CA1265580A - Secondary battery - Google Patents

Abstract

Abstract of the Disclosure This invention provides a secondary battery in a nonaqueous type using a substance indicated in I below and/or a substance indicated in II below as an active material for either of positive and negative electrodes:
I: a composite oxide possessing a layer structure and represented by the general formula:
AxMyNzO2 wherein A stands for at least one alkali metal, M for a transition metal, N for at least one member selected from the group consisting of Al, In, and Sn, and x, y, and z respectively for the number falling in a specific range, II: an n-doped carbonaceous material which has a BET-method specific surface area, and a crystal thickness, Lc, in the X-ray diffraction and a true density, ?, both having the values falling in a specific range, The secondary battery of this invention is small and light, excels in cyclicity and self-discharging property, and possesses a high energy density.

Description

~265S8~

Secondary battery BACKGROUND OF TH~ IN~ENTION
Field of the In~ention This in~ention relates to a novel secDndary battery and particularly to a small, light secondary battery.
Descliption of the PriDr Art In receDt years, electronic deYices haee been rematkably reduced in size and ueight and, as a natural consequence, 10 ha~e been urging batteries, i.e. power sources therefor, to come in proportionately reduced sizes and weights. In the field of primarY batteries, reductions in size and ueight ha~e already been Tealized as in lithium cells. Since these are primary batteries, they cannot be recharged for repeated use 15 and, therefore, ha~e found utility in limited applications. In the field of secondar~ batteries, lead acid batteries and nickel-cadmium batteries ha~e heretofore been used. These t~o types of secondary batteries both ha~e posed a serious proble~
with respect to reduction in size and seight. ~rom this point 20 of ~ie~, nonaqueous secondary batteries ha~e been arousing a greet interest but still need to be ~ull~ de~eloPed ~or practicability. One of the Teascns for the lack of practicability is that none of the acti~e materials so far de~eloPed for use in the aforementioned secondary batteries 25 satisfg such practical properties as cyclicity and self-~`

~ 2 dis~harging property.
Meanwhile, a new group of electrnde acti~e materials which make use of the phenomenon of inteTcala$ioD or doPing of a layer cDmpou~d, a fDrm o~ reaction substantial ly dif~erent from the reaction occurring in the conPentional nickel-cadmium batteTies and lead acid batteries, ha~e come to attract growing attention.
Since these new electrode acti~e materials in~ol~e nD
complicated electrochemical reaction during the course of recharging and discharging, they are e~pected to ha~e a highly ad~antageous cyclicity of recharging and discharging.
As e~amples of the electrode acti~e material making use of the intercalatinn of a layer compound, chalcogenide type compounds which possess a lamelar structure are attracting attention. ~or e~ample, such chalcogenide compounds as LixTiS2 and LixMoS3 e~hibit relati~ely satisfactory cyclicity but possess such low magnitudes of electromoti~e force that their practical discharge ~oltage is about 2 V at most eqen when Li metal is used as a negati~e electrode. With respect to the high electromoti~e force which constit~tes one of the chaTacteristics of nonaqueous batteTies, kheTefore, these compounds are not satisfactorY. Such metal 02ide type compounds as LixV20s, ~ixV6013, LixC002, and LixNiO2 are attracting attention in resPect that they are characterized bY
possessing high magnitudes of electromoti~e force. These metal ~65SB~:) o~ide type compounds, houe~es, aJe deficient in cyclicity and utility, namelY the propoltion in whir.h the compounds are utilizable for actual recharging and dischaTging, and further in terms Df the factDI of o~er~nltage in~ol~ed during the course of recharging and discharging. They have not yet been fully de~eloped to the le~el of practicability.
Particularly, such secondary-battery positi~e electrodes of LixCoO2 and LixNiO2 as disclcsed in Japanese Patent Application Laid-open No. 136131/1980 possess magnitudes of 10 electromotive foJce e~ceeding 4 Y when Li metal is used as a negative electrode and e~hibit surprisingly high magnitudes of theoTetical energy densitY (per positi~e electrDde acti~e material) e~ceeding 1,100 WHr/kg. They ne~ertheless possess lou proportions a~ailable actually for recharging and 15 discharging and pro~ide le~els of energy densitY falling far short of theoretical ~alues.
As one e~ample of the electrode acti~e material utilizing the phenomenon of doPing, a secondary batterY of a new type using an electroconducti7e macromoleculaT compound as 20 an electrode material is disclosed in Japanese Pat~nt Application Laid-open No. 136469/1981. The secondary batter~
using this electroconductive macromolecular compound, however, entails seTious outstanding problems such as instable properties e~inced by low cyclicity and large self-discharge 25 and has not yet reached the le~el of practicabilitY.

~2655~3~

In the specificati Dn S O f Japanese Patent Application Laid-open ~lo. ~5881~198~, No. 17~979/1984, and No.
207568/1884, it is prcposed to use large surface-area caTbon materials li~P acti~ated carbon as electrDde materials. Shese 5 electrode mateTials ha~e been found to manifest a specific phenomenon which, unlike the phenomenDn of doPing, is ptesumably ascribable to the formatio~ of an electric double layer due to their large surface areas. They are claimed to manifest conspicuous properties particularly when they are used in positi~e electrodes. It is furtber stated that they are usable paTtly in negati~e electrodes. When these large surface-area carbon materials are used in negati~e electrodes, howe~er, they betray serious draubacks in cyclicitY and self-discharging property. Moreo~er, the utilization lS coefficient, i.e. the pToportion of electrons (or paired cations) re~eTsibly released or recei~ed per carbon atom, is e~tremely low, e~en falling below 0.05 and generally falling in the range of 0.01 to 0.02. This fact implies that when these materials are used in negati~e electrodes of secondarY
20 batteries, the negative electrodes become ~ery large both in weight and ~olume. This point pO909 a serious obstacle on the way to actual adoption of the matetials.
The specification of Japanese Patent Application Laid-open No. 209864/1983 discloses adoption as electrode materials of such carbonaceous materials as carbonated phenolic .

~ 6 5 S~

fibers whose hydrogen atom/carbon atom ratio falls in the range of 0.33 to 0.15. It has a descTiption to the effect tbat the carbonaceous materials manifest paJticularly desirab]e properties ~hPD ~hey ale used as positi~e electTode materials p-doped mainly with anions and that they aTe also usable as negati~e electrode materials n-doped with cations. These materials ha~e a serious disadvantage that they are deficient in cyclicitY and self-dischaTging propert~ when they are used as n-doped negatiYe electrodes. They ha~e another serious disad~antage that they possess e~tremely low utilization coefficients and lack practicability.
It has long been known to use graphite layeT compounds as electrode materials for secondary batteries. It has been known to the art that graphite layer compounds ha~ing incorporated therein such anions as Bre, Cl~4e, and BF4e ions are usable as positi~e electrodes. It is naturally concei~able that graphite layer compounds ha~ing incorporated therein such cations as Li~ ion are usable as negati~e electrodes. In fact, the specification of Japanese Patent Application Laid-open ~o.
143280/1984 discloses adoption as negati~e electrndes of graphite laYer compounds which ha~0 incarporated therein cations.
The graphite layer compounds which ha~e incorporated therein cations, howe~er, ars highly instable. ParticulaTlY

2~ the fact that they possess e~tremely high reacti~ity with : . ~
, ~s~
electrolytes is evident from the report published by A.N.
Dey, et al. in the "Journal of Electrochemical Society,"
Vol. 117, No. 2, pp 222-224, 1970. When the graphite which is capable of forming a layer compound is used as a negative electrode, this negative electrode is hardly practicable because it lacks stability of the self-discharging property necessary for a ~attery and shows an extremely low utilization coefficient.
The new group of electrode active materials which utilize the phenomenon of intercalation or doping in their current conditions are such that the properties which are inherently expected of the materials have not yet been realized from the practical point of view.
SUMMARY OF THE INVENTION
This invention has been completed for the purpose of solving the various problems mentioned above and thereby providing a small, light secondary battery which excels in battery properties, particularly cyclicity and self-discharging property and possesses a high energy density.
This invention provides a secondary battery comprising positive and negative electrodes, a separator, and a nonaqueous electrolyte, wherein said secondary - battery is characterized by having as an active material for said positive electrode a material as indicated in I
below and for said negative electrode a material as indicated in II below;
I : a non-carbonaceous active material, and II : a carbonaceous material which has a BET-method speci~ic surface area, A~m2/g), being Ln the range of 0.1<A ~100 and a crystal thickness, Lc(A), hased on X-ray di~fraction and a true density, p(g/cm3), which satisfies the conditions, 1.80~ p ~2.18, 15~ Lc and 120 P-227<Lc<120 p-18~.
This invention also provides a secondary battery comprising positive and negative electrodes, a separator, and a nonaqueous electrolyte, wherein said secondary ~6~

battery is characterized by having as an active material for said positive electrode a material as indicated in I
below;
I : a composite oxide possessing a layer structure and represented by the general formula:
AXMyNzo2 wherein A is at least one member selected from the group consisting of alkali metals, M is a transition metal, N is at least one member selected from the group consisting of Al, In, and Sn, and x, y, and z satisfy the expression 0.05< x <1.10, 0.85<y ~1.00, and 0.001 <z <0.10, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a sectional view showing a structure of the secondary battery of the present invention. In this diagram, 1 stands for a positive electrode, 2 for a negative electrode, 3 and 3' for current collecting rod, 4 and 4' for SUS nets, 5 and 5' for external electrode terminals, 6 for a battery case, 7 for a separator, and 8 for an electrolyte or solid electrolyte. Fig. 2 is a graph illustrating the relation between the charging and discharging voltage and the utilization coefficient obtained by charging and discharging the secondary battery of........................................................

126S5~0 E~ample 1. Fig. 3 to ~ig. 7 illustrate the changes of current efficiency (brDken line) and utilizatio~ coefficient uith the char~ing and dischatging cycl~. Fig. 3-A shows the res~lts of E~ample 1, Fig. 3-B those of Comparati~e E~periment 2, Fig. 4-A
those of E~ample 11, Fig. 4-B those of E2ample 16, Fig. 4-C
those of Comparati~e E~periment 10, Fig. 5-A those of E~ample 18, Fig. 5-B those of E~ample 23, ~ig. 6-A those of Example 24, Fig. 6-B those of Comparative E~periment 18, Fig. 7-A those of E~ample 33, and Fig. 7-B those of E~ample 36. Fig. 8 is a graph illustrating the constant current, charging ~oltage, and discharging ~oltage of the battery of E~ample 42. Fi~. 9 is a graph illustrating the charging Poltage and discharging ~oltage when the chaTging and discharging cycle of the battery of E~ample 42 has counted 500.
DETAILED DESCRIPTION OF THE INVENTION
The novel composite lay0r metal o~ide of the present in~ention is represented by the general formula, AxMyNz 02 .
wherein A is at least one member selected from the group of alkali metals such as, for e~ample, Li, Na, and K. Among the 20 alkali metals cited abo~e, Li pro~es particul~rlY d~sir~ble.
The ~alue of r ~eries in th~ rang0 of 0.05 ~ ~ S 1.10, dePending on the condition of char8ing and the condition of discharging. B~ the charging, the A~ ion undergoes deintercalation and the ~slue of ~ decreases. In the condition 25 Df cDmplete chargin8, the ~alue of ~ reaches 0.05. By the 1 2~55~

discharging, the A~ ion undergoes intercalation and the ~alue of ~ increases. In the condition of complete discharging, the ~alue of ~ reaches 1.10.
In the general formula, M stands foT a tTansition metal. In all the tTansition metals effecti~ely usab3e hesein, Ni and ~o pro~e partiCU]aT]y desirable. The Qalue of y does not ~ary by charging or discharging and falls in the range of 0.85 ~ y S 1.00. If the ~alue of y is less than 0.8~ or more than 1.00, theTe ensue such undesiTable phenomena as degradation of cyclicity and ele~ation of o~er~oltage which are detrimental to the acti~e material for a secondary battery.
In the geneTal formula, N stands for at least one member selected from the group consisting of Al, In, and Sn. Among the members cited above, Sn pro~es particularlY desiTable. In lS the actiYe material for $he no~el secondary battery of the present in~ention, N fulfils an extremely important function in impro~ing the cyclicity particularly in d0eP charging and deeP
discharging cycles. The value of z does not vary by chaTging OT discharging and falls in the range of 0.001 S z ~ 0.10, 20 preferably in the range of 0.005 ~ z S 0.075. If the ~alue o~
z is less than 0.001, the effect of N is not sufficie~tly manifested and the cyc~icitY in deep charging and deeP
discharging is degraded and the overvoltage during the course of deeP charging is greatlg increased. If this value ezceeds 25 0.10, the hydroscopicity of the acti~e mateTial is enhanced so 1265~i~30 mucb as to Tender handling difficult and the basic properties of the acti~e matelial are impaired.
The cDmposite o~ide for the acti~e material Df the noYel secondary battery of the present inYention can be prDdured b~
mi~ing o~ides, hydro2ides~ caTbona$es, nitrates, or otganis acid salts of the metals of A, M, and N and fiTing the resulting mi~ture in tbe air or in an atmosphere of o~ygen at a temperature in the range of 600 to 950C, prefeTably 700 to 900C.
10The time sufficient for the firing generally falls in the range of 5 to 48 hours. The composite o~ide, AxNyN202, which is obtained by the method descTibed abo~e has as a positiqe electrode of a secondary battery such a condition of discharge that the ~alue of ~ generally falls in the range of 0.90 to 1.10.
The composite o~ide, AxNyNz02, obtained as described aboqe undergoes the reaction of deintercalation and the reaction of intercalation by charging and discharging and, as a result, the qalue of x qaries in the range of 0.05 C r C 1.10.
20The reactions mentioned aboqe ure e~pressed by the following formula.

A ~M N202~ Charglng ~ Ax~MvNz02 ~ Xr)A~
Discharging ~ (r' - X~)ee wherein ~' stands for the qalue of x before charging and X~ for the qalue of ~ after charging.

~2655~30 The aforementioned ~utili2ation coefficient~ denotes a ~alue which is de~ined by the follouing formula.
Utilization ~oe~ficient = ~ ~ z ~ 1~0 (%) The acti~e material for the no~el nonaqueous secondarg batteTy of the present in~ention is characterized b~ haYing a large utilization coefficient. In other words, it e~hibits a ~ery stable cyclicity with respect to deeP charging and discharging.
The composite o~ide as the acti~e material for the no~el secondary battery of the present invention possesses a ~ery noble potential of the order of 3.9 to 4.5 V relati~e to the Li standard potential and manifests a particularly satisfactory function when it is used as a positi~e electrode for a nonaqueous secondary battery.
The carbonaceous material to be used in the present in~ention requires to possess a BET-method specific surface area, A (m2tg), not less than 0.1 and less than 100, desirablY
not less than 0.1 and less than 50, and more desirablY not less than 0.1 and less than 25.
If this specific sur~aoe area is less th~n 0.1 m2/gl the surface area is too small for the electrochemical reaction to proceed smoothly on the surface of the electrode. If the specific s~rface area is not less than 100 m2/g~ such properties as cycle life property, self discharging property, ~2655~30 and culrent efficiencY are degraded notably. The degTadation of such properties maY be IDgically egplained by a supposition that since the surface area is SD large, ~arious secondary reactiDns are suffered to occur on the su~faoe cf the eleotrode and e~ert adYe~se effects on the batter7 prDpe~tiPs.
Further, the ~alues of the crYstal thickness, Lc (A), in the X-ray diffraction and the true density, ~ (g/cm3), are required to satisfy the follouing cDnditions.
1.70 ~ p < 2.18 and 10 ~ Lc c 120p - 189 Desirably, the ~alues satisfy the conditions, 1.80 C p ~
2.16 and 15 ~ ~c C 120p - 196 and Lc ~ 120p - 227. More desiTablY, the ~alues satisfg the conditions, 1.96 ~ p ~ 2.16 and 15 ~ Lc ~ 120p - 196 and Lc ~ 120p - 227.
In this invention, the aforementioned ~alues of the crystal thickness, Lc (A), in the X-ray diffraction diagram and the true densit~, p (g/cm3), are extremely important ~hen the n-doped caTbonaceous material is used as a stable electrode acti~e material.
For e~ample, if the ~alue of p is not moTe than 1.70 or 20 the ~alue of ~c is not more thau 10, the carbonaceous material is not in a sufficiently carbonized state. Thi 9 ~uc t m0ans that ample crystal growth of casbon has not proceeded in the carbonaceous material and an amorphous phase occupies a ~ery large proportion of the carbonaceous material. So long as the carbonaceous material has the aforementioned ~alues belo~ the ~655~0 lower li~its of the specified ranges, it necessarilY acquiJes a large surface area deParting from the range nf BET-mPthod specific surface area of this in~ention during the course of carboDization. WhPn the carbonaceous mate~ial of this 5 descriPtion is n-doped, the n-doped material is ~ery instable and the e~tent of doping itself is so small that the material cannot stably e~ist substantially as an n-doped composite and cannot be used as an acti~e material foT a battery.
If the ~alue of p e~ceeds 2.18 OT the ~alue of ~c 10 e~ceeds the difference, 120p - 189, the carbonaceous material has been carbonized to e~cess. This fact means that the carbonaceous ~aterial assumes a structure resembling graPhite in consequence of ad~anoed crystallization of carbon.
Besides the true densitY, p (g/cm3), crystal thick~ess, 15 Lc (A), and BET-method specific surface area, A (m2/g), defined in the present in~ention, the intersurface distance, doo2 (~), based on the X-ray diffraction is giveD for e~a~ple as a parameter to indicate the structure of the abo~e carbonaceous material. The ~alue of the interface distance, doo2 tA).
20 becomes small as the crystallization procceds. Although it i9 not particularl~ defined, the c~rbonaceous material having the value of less than 3.43A OT less than ~.46~ does not fall in the range defined by the present in~ention.
Mean~hile, the value of the aforesaid Raman strength 2~ ratio, R (I 1360 cm-~/I 1580 cm-l), is also a parameteT tD

~ 6 S S ~

indicate the structure of ~he carbonaceous material. This qalue becomes small as the crystallization proceeds. AlthDugh it is nDt paTticularl~ defined, the carbonaceDus material haYing the ~alue less than 0.6 or not less thaD 2.5, OT the carbonaceDus matelial ha~ing the ~alue of less than 0.7 or not less than 2.5 does not fall in the range defined by the present in~ention.
Graphite has a regular layer stsucture as described abo~e. A carbonaceous material of such a structure forms a laye~ compound using a varying ion as a guest and a p t~pe layer compound with an anion such as ClO4e or BF4~ possesses a high potential. Attempts ha~e long been made to realize use of such a carbonaceous material as a positi~e electrode in a secondary battery. ~or this purpose, it is an essential lS requisite that the carbonaceous material should be capable of easily forming a layeT compound. To be specific, as indicated in the specification of Japanese Patent Application Laid-open No. 36315/1985, it is a requisite that the Baman strength ratio, R (I 1~60 cm-1/I 1580 cm~1), should be as small as possible, i.e. the ~alue of p and the ~alue of Lc shDuld be as large as possible.
The in~entors, while performing ~arious studies diTected from a different point of ~iew to the incorporation in the cerbonaceous material of cations such as Li~ ion instead of anions, made an une~pected disco~er~. Specifically they ha~e ~2655~

found that for the incorporation of such cations as Li~ ion, the carbonaceous material aquires betteT properties when it possesses aD iTregular structure to some e2tPnt. When the carbonaceous materia3 to be used possesses a value uf p e~ceeding 2.18 and a ~alue of Lc e~ceeding the differe~ce of 120p - 189, since it displays a behavior like graphite as described abo~e, the secondary battery using this carbonaceous material pDssesses poor cycle life property and self-discharging property, shows a ~er~ low utilization coefficient, and in an e~treme case substantially fails to function as a battery.
The carbonaceous material fulfilling the rEquirements imposed by the present in~ention is obtained by subjecting a Yarying organic compound to thermal decomPositioD or to carbonization by firing. In this case, the thermal hysteresis temperature condition is important. IT^ the thermal hYsteresis temperature is e~cessi~ely ]ow, the carbonization does not sufficiently proceed. The carbonaceous material consequently obtained not merely shows low electroconducti~ity but also fails to fulfil the conditions essential for this inYention.
The lower limit of this temperature is geneT~ 600C, preferably B00C, though ~ariable to some ertent. More important is the upper limit of the thermal hysteresis tempersture. By the heat treatment generally carried out at temperatures near 3,000C ~or the productiDn Df graphite and ~;~655i3~

casbon fibers, the growth of crystals proceeds e~cessiYely and the function of the secondary battery acti~e material is seriously impaired. Thus, the upper limit of the thermal h~steresis temperature is 2,400~, desirablY 1,800C, and more 5 desirably 1,400C.
In the abo~e heat treatment, the conditions such as a tempeTature increasing rate, a cooling rate, and a heat treating time can be determined depending on the objecti~es contemplated. A metbod which effects the heat treatment at a relati~ely low range of temperature and then, increases to a predetermined temperature may be adopted.
As one e~ample of the carbonaceous material fulfilling the specific range~ imposed by this in~ention, carbon fibers prDduced by the vapor-phase growth method can be cited. The carbon fibeTs of the ~arpor-phase growth method are a carbonaceous material obtained, as disclosed in the specification of Japanese Patent Application Laid-open No.
20782~/1984, by subiecting a carbon-source compound such as benzene, methane, or carbon monoxide to a ~apor-phase thermal decomposition (at a temperature in the rung0 o~ 600C to 1,500~, for e~ample) in th0 presenc~ of a transition met~l catalyst. All the products obtained by known similar methods are embraced by the carbonaceous material conte~plated by this iDvention. ~ethods which effect the formation of such fibers on substrates (such as, for e~ample, plates of ceramic and s~o graphite and palticles of carbon fibers, carbDn black, and ceramic) and methods which effect the formation i~ a ~apor phase are counted among such kno~n methods. Generally b~ these methods, carbDnaceous materials are obtained in the foT~ o~
carbon fibers. ID the present in~ention, such carbonaceous materials may be used iD their fibrous form. Otherwise, they may be used in a pDwdeTed fDr~.
It is a well-known fact that the carbon fibers of the ~apoT-phase growth method are a typical e~ample of readily graphitizing carbon. In other ~ords, the caTbon fibeTs are characterized by being graphitized with e~treme ease. The heat treatment foT the graphitization is generally caTTied out at a temperature e~ceeding 2,400C. The graphitized carbon fibers of the ~apor-phase growth method ha~e been already reported as possessing ~arious characteristics beneficial for their adoption as graphite materials of a highly ordeTly crystalline StTUCtUTe. ~ndo et al., for example, ha~e published in the "Synthetic Metals," ~ol. 7, p. 203, 1983 their obser~ation that the carbcn fibers and an anion such as Br~ jointly form a laYer compound ~ith estreme e~se and that a temperatur~ dif~erence batter~ oan be obteined by using the lager compound with the anion as a positi~e electrode and a negati~e electrode. This battery, houe~er, generallY possesses an e~tremely low electromoti~e force and hardly suits actual adoption.
Graphite has a regular layer structure as described ~2 6 ~ S ~ O

abo~e. A carbonaceous mateTial of such a structure forms a layer compound using a ~arying ion as a guest and a layer compound ~ith an anion such as ~lO4e or BF4e pDssesses a high potential. ~ttemp~s ha~e long been made to realize ~se of such 5 a carbonaceDus material as a positi~e electrode in a secondary battery. For this purpose, it is an essential requisite that the carbonaceous material should be capable of easily forming a layeT compou~d. To be specific, as indicated in the specificatioD of Japanese Patent Application laid-open No.
10 36315/1985, it is a requisite that the heat treatment should be carried out at a temperatuTe near 3,000C and the treated carbonaceous material should assume a structure of graphite.
The in~entors, while perfor~ing ~arious studies directed from a different point of ~iev to perfecting an n-doped material 15 incorporating therein cations such as Li~ ion instead of anions, made an une~pected discoverY. Specificallg they ha~e found that for the incorporation of such cations as Li~ ion, the carbonaceous material acquires better properties when it has not undergone e~cess thermal hysteresis.
The carbon fibers of the ~apor-phase grouth m~thod to b0 used in the pres0nt invention pro~0 to b0 ad~antag~ous vhqn the highest thermal hysteresis temperature encountered in the whole operation including e~en the step of production is not higher than 2,400C, desirably not higher than 2,000C, and more 25 desirably not higher than 1,400C. If this temperature e~ceeds .. .. .

~ 6 ~

2,400C, the heat treatment brings about ad~eTse effects on the properties of the n-doped materia].

Another e~ample of the carbDnaceDus material usable as the acti~e material is a pitch type car~onaceous matesial. As 5 concrete e~amplPs of the pitch usable in this in~entiDn, theTe may be cited petroleum pitch, asphalt pitch, coal tar pitch, crude oil cracked pitch, and petroleum s]udge pitch, namely pitches obtained bY thermal deco~pDsition of petroleum and coal, pitches obtained by thermal decomposition of 10 macromolecular polymers, and pitches obtained by thermal decomposition of organic low molecular compounds such as tetrabenzophenazine.
~ or the production of a pitch type fired carbonization PToduct fulfilling the conditions of tbe present in~ention, the 15 thermal hysteresis temperature condition is important. The ther~al hysteresis at an e~cessi~ely high temperature gives rise to an excessi~elg crystallized carbonaceous material and seriously impairs the properties of the n-doped materia]. The thermal hysteresis tempeTature is not higher than 2,400C, 20 desirably not higher than l,~OO~C, ~nd more desirublY nDt higher than l,400~C.
The lower limit of the tempeTature is 600C, the le~el at which the fired carbonization product begins to manifest electroconducti~ity and other similar properties, and more 25 desirably 800C.

~ 2 ~ 5 ~ ~

One concTete e~ample of the pitch type fired carbonization product is needle coke.
Another e~ample of the carbonaceDus matPrial to be used in the present in~ention is a fired carbonization prDduct of a polymeJ formed pTeponderantly of acr~lonitrile. ~DT the PToduction of the fired caTbonization product of a pDlymer formed preponderantlY of acrylonitrile whioh fulfils the conditions of the present invention, the thermal hysteresis temperature condition is important. As described abo~e, the thermal hysteresis at an e~cessi~ely high temperature giYes rise to a fired carbonization product of e~cessi~e crystal growth and seriously impaiTs the properties of the n-doped material. The thermal hysteresis temperatuTe is not higher than 2,400C, desirablY not higher than 1,800C, and moTe desirably not higher than 1,400C.
The ]ouer limit of the temperature is 600C, the level at which the fired carbonization product begins to manifest electroconducti~ity and other similar propeTties, and more ~esirably 800C.
It is e~ident from the results of the X-ra~ analysis, the Raman anulysis, and the tru0 densit~ me~surement thet, unlike the ordinary graphite, the carbonaceous material of the present in~ention does not possess a layer structure capable of forming a layer compound. In fact, the carbonaceous material 25 satisfying the requirements of this invention is totallY

~2655~3~

incapable or sparinglY capable of incorporating therein such anions as ClU4e, B~4e, and Bre which readily form a layer compound jointly with graphite.
It is also a fact that unlike the large surface area carbonaceDus material like acti~ated carbon which, as described in the specification of Japanese Patent Application Laid-upen No. 35881/1983, forms an electric double layer on the surface thereof, thP beha~iDr of a capacitor of a sort, the carbonaceous material of the present in~ention is such that 1~ there e~ists absolutely no correlation between surface aJea and battery properties and that an increase in surface area rather has an ad~eTse effect on such properties as current efficiency and self-discharging property.
The facts mentioned abo~e diffet from the phenomena obser~ed in the con~entional carbonaceous material and manifest the following characteristics when the carbonaceous material is used as an acti~e material for a secondary battery. As concerns the cycle life property, the secondary battery using the carbonaceous material pro~ides at least 100 cycles, more than 300 cYcles when cDnditions permit, or e~en more than 500 cycles under fa~oTable conditions. The current ef~iciency in chsrging and discharging is st le~st SOX, more than 95X wben conditions permit, and e~en more than 98X under fa~orable conditions. The self-discharging propertY is not more than 30%~month, not more than 20X/muDth when conditions permit, and ~ ~ 5 5 ~

eQen not more than 10%/moDth under fa~orable conditions. As one of the characteristics of the carbonaceous material satisfying the conditions of the present invention, the very large uti]ization coefficient can be cited.
~y the term "utilization csefficient" used in the present in~ention is meant the proportion of electrons (or paired cations) reYersibly Teleased and tecei~ed per carbon atom. It is defined by the following fDTmula.
Amount of charged and Utilization discharged electricity (in AHr) coefficient ~ 12 ~ 26.8 wherein w stands for the weight of the carbonaceous material used, in g. In the present in~ention, the utilization coefficient is at least 0.08, preferably not less than 0.15.
1~ Thus, the secondary battery small in weight and ~olume is enabled to store a large amount of electricity.
The n-doped carbonaceous material of the present in~ention manifests its e~cellent properties to ad~antage when it is used as an acti~e material for a secondary battery, particularly as an acti~e material for a negati~e electrode.
Now, the secondary battery using the acti~e material of the present in~ention will be described below. In the production of the electrode by the use of the acti~e material for the secondary battery of this in~ention, the acti~e materi~l can be used in a ~arying form.

~ ~ 6 5 5 ~ ~

For e~a~ple, the acti~e material may be in the foJm of film, fibers, or p~wder, depending on the nature of application contemplated. Particularly wheD it comes in the ~Drm of powder, it may be molded in the shape of sheet, fol e~ample.
As regards the manner of molding, the method uhiGh comprises t~ f~ f /~ o~v ~ fJ~ e n e mi~ing the acti~e mateTial with such a Po~dery binder as ~e$~n powder or polyethglene powder and compression molding the resulting mi~ture is generally adopted.
Preferabl~, the method which effects the molding of the acti~e material bg using an organic polymer dissol~ed and/or dispersed in a sol~ent as a binder can be adopted.
The nonaqueous batteries enjoy such merits of quality as high energy densitY and small size and light weight. They ha~e not yet found e~tensi~e utility in general applications, howe~er, because they are inferior to the aqueous batteries in terms of output propeTties. Particularly in the field of secondary batteries which are expected to possess sufficient output propeTties, the drawback just mentioned constitutes one of the main causes for pre~enting the nonaqueous batteries from finding practical utilit~.

The infeTior output properties of the nonaqueous batteries are ascribed to the fact that the nonaqueous batteries generally possess such low degrees of ion conducti~ity as 10-2 to 10-4 Q ~Icm-l, whereas the aqueous batteries possess high degrees of ion conducti~ity generally on ~ 2 6 5 the order of 10-~ Q-lcm-l.
As one means of sDl~ing this problem, the idea of increasing the surface area of an electrode, namel~ using aD
electrDde of a thin membrane ha~ing a large suTiace area, may be concei~able.
The method described abo~e is particulaTly ad~antageous for the production of an electrode of a thin membrane ha~ing a large surface area.
For the use of the aforementioned organic polymer as a binder, there may be employed a method uhich comprises preparing a liquid binder by dissol~ing the organic polymer in a sol~ent, disPersing the acti~e material for an electrode in the liquid binder, and applying the resulting dispersion on a gi~en substrate, a method which comprises emulsifying the organic polymer in water, dispersing the actiYe material in the aqueous emulsion, and applying the resulting disPersion on a substrate, or a method which comprises premolding the active material and applying a solution and/or dispersion of the organic polymer on the premolded article of the acti~e material. The amount of the binder is not specifically defined. Generall~ it ialls in the range of 0.1 to 20 partg b~
weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight oi the active material ior an electrode.
The organic polymer to be used herein is not specifically defined. When the organic polymer to be used is .

; ;-.........

.

~ 6 5 S~O

of a t~pe haYing a sperific dielectric constant e~ceeding 4.5 at 25~C and 1 KHz of fTequency, it brings ahout particularly desirable Tesults and e~hibits Dutstanding batteJy performance as in cyclicity and o~er~oltage. A~ concrete egamples of the organic pol~mer satisfying this requirement, there may be cited acrylonitrile, methacrylonitrile, vin~l fluoride, ~inylideDe fluoride, chlorDprene, ~inylidene chloride, and othet similar polymers, copolymers thereof, and nitrocellulose, cyanoethyl cellulose, and polysulfide rubber.
The electrode is produced by applying the aforementioned coating liquid on a substrate and drYing the applied coat. In this case, the acti~e material may be molded jointly with a material for the collector. Alternati~ely, a collector made of an aluminum foil or a copper foil may be used as the substrate for application of the coating liquid.
The electrode for the battery produced by using the active material of the present in~ention may incorporate therein a conductor aid and other additi~es besides the aforementioned binder. It is a requis;te that the electrode should contain the acti~e materi~l of this in~ention in a concentration of dt least 25% by weight.
As examples of the conductor aid, metal powders, conducti~e metal oxide powders, and carbons may be cited. The incorporation of the conductor aid manifests a conspicuous effect when a composite o~ide Ax~vN202 defined in I as the ~ 2 ~ S ~ ~ ~

acti~e material of this in~entioD is used.
Among the conductor aids cited abo~e, carbon ~iYes palticulaTly desirable effects. When the catbD~ is incorporated in the electrDde in a conoentration of 1 to 30 parts by weight based on 100 parts by weight of AxMyNzO2, it manifests conspicuouslY its effect of notably loweTing the o~ervoltage and improYing the cyclicity. This carbon refeTred herein is required to haYe the propeTties quite different fr~m the carbonaceous material II defined in this invention and does not always indicate a specific carbon. Concrete e~amples of the carbon are graphite and carbon black. The effect manifested by the carbon is especially conspicuous when the carbon is a combination of two grades of carbon, one ha~ing an a~erage particle diametet of 0.1 to 10 ~ and the other an a~erage lS particle diameter of 0.01 to 0.08 ~.
As described abo~e, the acti~e material, AxMyNzO2, o~
this in~ention indicated in I manifests its effect particularly desirably when it is used as a positi~e electrode. Then, the material to be used as the negati~e electrode is not specifically defined. As concrete e~amples of the material for the negati~e electTode, there muy be cited light metals such as Li and Na, alloys thereoî, metal orides such as LixFe203, LixFe30~, and LixW02~ electroconducti~e macromolecular compounds such as pol~acetylene and poly-p-phenylene, carbon fibers of the ~apoT-phsse growth method, and carbonaceous 12~55~C~

materials such as pitch type carbon and polyacrylonitrile type carbon fibers.
The active material of this invention indicated in II manifests its effect more advantageously when it is used as a negative electrode as already described. Then, the material to be used as the positive electrode is not specifically defined. As examples o the positive electrode, there may be cited active non-carbonaceous materials, for example TiS2, TiS3, ~oS3, FeS2, Li(l-x)MnO2, Li(l_x)Coo2~ Li(l-X)NiO2/ V205~ and V613-The most desirable combination of electrodes is between a positive electrode made of the active material, AXMyNzO2l of this invention indicated as I and a negative electrode made of the active material of this invention indicated as II.
The basic components for the composition of the nonaqueous secondary battery of the present invention are the two electrodes using the aforementioned active materials of this invention, a separator, and a nonaqueous electrolyte.
The material for the separator is not particularly defined. Examples of the material include woven fabric, non-woven fabric, woven fabric of glass fibers, and porous membrane of synthetic resin. When the electrodes to be used are thin membranes of a large surface area as described above, use of a microporous membrane of synthetic resin, particularly of a polyolefin as disclosed in Japanese Patent Application Laid-open No. 5~072/1983 for example, proves to be desirable in terms of thickness, 30 strength, and membrane.............................. ~

. :.. ' . :
.

~2~5~

Tesistance.
The substance fol the nDDaqueous electrnlyte is not specifically defined. Concrete e~amples of the substance include LiCl~, LiBF4, LiAsF6, CF3gO3Li, LiPF6, ~iI, LiAlCl4, NaClO4, NaBF4, NaI, (n-Bu)4N~CI~4, (n-~u)4N~BF4, and KP~6.
Concrete e~amples of tbe organic sol~ent for the electrDlyte include ethers, ~etones, lactones, nitriles, amines, amides, sulfur compounds, chlorinated hydrocarbons, esters, carbonates, nitro compounds, phosphoric ester type compounds, and sulfDlane type compounds. Among the oTganic sol~ents cited abo~e, etheTs, ketones, nitriles, chlorinated hydrocarbons, carboDates, and sulfolane t~pe compounds pro~e particularly desirable. CYCI;C carbonates are most desirable selections.
As typical e~amples of the cyclic carbonate, there may be cited tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dio~ane, anisole, monoglyme, acetonitrile, propionitrile, 4-methyl-2-pentanone, butyronitrile, ~aleronitrile, benzonitrile, 1,2-dichloroethanel ~-butyrolactone, dimetho~Yethane, methyl formate, propylene carbonate, ethylene carbonate, ~inylene carbonate, dimethgl form~mide, dimeth~l sulfo~ide, dimethgl thicformamide, sulfolane, 3-methyl-sulfolane, trimethyl phosph~te, triethyl phosphate, and mixtures thereof. These are not e~clusive e~amples.
Optionall~, the secondary battery composed as described abo~e may further incorporate therein other parts such as current collectors, terminals, aDd insulation boards. The .

~2 6 5 5~ ~

structure of the battery is nDt specifically limited. A paper type batteTy ba~ing a positi~e electrode, a negati7e electTode, and optionally a separator superposed in a single layer or a plurality of layers, a lamination type battery, and a cylindJical battery ha~ing a positi~e electrode, a negati~e electrode, and optionallg a separator wound up in a roll aTe concrets e~amples of the battery structure.
The battery of the present in~ention is small and light and e~cels in cyclicity and self-discharging property and is highly useful as power sources for small electronic de~ices, electric motorcars, and electric power storages.
Now, the present invention will be descTibed more specifically belou with reference to working e~amples and compaJati~e experiments.
The X-ra~ diffraction was carried out by following tbe "Japan Learning and Study Ad~ancement Society Method~ with necessary modifications. The true density was determined by the float-and-sink metbod which comprises comminuting a gi~en carbonaceous material in an agate mortar into powder capable of passing a 150-mesh standard sie~e and placing the resulting powder as A sample in a mixed solution of bromo~or~ und c~rbon tetrachlotide nt 25C. In th0 c~se of a sample which had ~alues of true density distributed o~er a range, the ~alue of true densitY of about 50% of all the particles of the sample sank in the mired solution was reported as the result of ~Z655~0 determination.
The determination of Telati~e diele~tTic constant was carried out under the following conditions.
Temperature 25C
Frequency 1 kHz ~orm of sample Sheet 0.5 mm in thickness Apparatus DielectTic product testeT
~odel TR-lOC (AndD Electric Co., Ltd.) Example 1:
In an atmospheTe of Ar, anthracene oil of room tempeTatUTe was heated at a temperature increasing rate of 5C/min. to 1,200C, at which it was fired for carbonization for one hour. The BET surface area, the Lc~o o 2) based on X-ray diffraction, and the true densitY of the resulting carbo~aceous mateJial were 6Q m2/g, 25 ~, and 2.01 g/cm3 Tespecti~ely. 1'his sample was comminuted in a ball mill into powder ha~ing an a~erage particle diameter of 2 ~. A coating liquid was obtained by mixing 1 Part by weight of the poudered sample uith 2.5 paTts by weight of a solution of nitrile rubbeT
(relati~e dielectric constant 17.3) in methqlethql ketone t~
wtX in concentration). This co~ting liquid was applied in a thickness of 75 ~m on the surface, 1 cm r 5 cm, of a copper foil lO~m in thic~ness.
The coated copper foil was nipped bet~een SUS nets to form a negati~e electrode for a battery illustrated in Fig. 1.

3 0 1~ 6 5 ~ ~

Separately, a mi~ture consisting of 1.05 mo]s of lithium carbonate, 1.90 mDls of cobalt ozide, and 0.084 ~DI of stannic ogide was calcined at 650~ fDT 5 hours and then fired in the air at 8~0C for 12 hours. Consequently, there ~as obtained a composite o~ide of a composition of Lil 03COO. 95SIlO 04202 ~
This composite o~ide was comminuted in a ball mill into powder ha~ing an a~erage particle diameter of 3 ~m. One Part by ueight of the poudered composite o~ide was mi~ed with 0.1 part by weight of acetyleDe black and 1 part by weight of a solution of polyacrylonitrile (relati~e dielectric constant 5.59) in dimethYI foTmamide (2 ~t% in concentration). The resulting mi~ture was applied in a thickness of 100 ~m on oDe surface, 1 c~ ~ 5 cm, of a~ aluminum ~oil 15 ~m in thickness.
The coated aluminum foil was nipped between SUS nets to foTm a positive electTode. A battery using the two electrodes mentioned abo~e was e~aluated, with a solution of 0.6 mol o~
LiCI04 in propylene carbonate used as an electrolyte.
As a separator, a micropoTous polyethylene membrane 35 ~m in thickness uas used.
When the batterg was charged at a constant current of 2 mA for 50 minutes, it shou0d un op~n terminel ~oltuge of 3.9 V. The proportion of ~i~ ion taken in per carbon atom by this charging, namely the utilization coefficient, was 0.12.
Thereafter, the battery was discharged at the same constant current of 2 mA until the ~oltage fell to 2.7 V~ The charging ~26ss~o ~oltage and the discharging ~oltage in~ol~ed at this time ~ere as shown in Fig. 2 and the o~er~oltage was as low as 0.04 Y.
Thereafter, a charging-discharging cycle (charge stop ~oltage 3.95 V and discharge stop ~oltage 2.7 V) uas Tepeated at a constant cuTTent 2 mA. The changes of current efficiency and utilization coefficient along the SUCCPssioD of c~c~es are shown in Fig. 3-A. The energy density (peT acti~e material for negatiYe electrode) in the 5th cycle uas 911 Whr/kg.
The battery, after 720 hours' standing at 25C, shnwed a self-dischaTge ratio of 15%.
E~amples 2-6 and Comparati~e E~periments 1-5:
The ra~ mateTials shown in Table l uere carbonized by firing or thermallg treated under the conditions similarly shown in Table 1. Batteries using the resulting carbonaceous 1~ materials were e~aluated b~ following the procedure of E~amp]e 1.
The data obtained in this test coDcerning the current efficiency and the proportion of Li~ ion taken in re~ersiblY
per carbon atom, namely the utilization coefficient, were as shoun in Table 1.
Table 1 also shows the data concerning th~ BET surfac0 area, the Lc~002) b~sed on the X-ray diffruction, ~nd the true densitg. Concerning Comparati~e Erperiment 2, the changes of current efficiency and utilization coefficient during a long series of cycles are shoun in Fig. ~-B. The energy densitg ~ ~ 6 ~ S ~ 0 (per acti~e material for negati~e electrode) in the 5th c~cle ~as 288 Whr/kg. The batter~ of Comparati~e E~periment 2, after 720 hDurs' standing at 25~C, shoued a sPlf-discharge ratio of 85%.

T a b I e Raw material Conditions of treatment BET ILc(00 sur f are area (m2 ~g) (~) . _ _ E~a~plP 2 Anthracene oil Sample of E~ample 1 23 45 1400C, 30 min.
(in Ar) _ Comparati~e Anthracene oil Sample of E~ample 1 9 500 E~periment 1 3000C, 30 min.
~in Ar) _ E~ample 3 Tetrabenzo- Temp. increasing rate 33 25 phenazine of 5C/min., 1200C, one hour (in Ar) _ _ E~ample 4 Tetrabenzo- Sample of E~ample 3 21 55 phenazine 1600C, 30 min.
(in Ar) _ Comparati~e Tetrabenzo- Sample of E~ample 3 11 280 Experiment 2 phenazine 3000C, 30 min.
(in Ar) E~ample 5 Coal tar Temp. increasing rate 17 35 of 5C/min., 1400C, one hour (in Ar) .
Comparati~e Vinyl chloride 300C, one hour tin air)755 C 10 Egperiment 3 Temp. increasing rate of 5C/min., 1000C, one hour (in Ar) Egample 6 Vinyl chloride Sample of Comparative 4 36 E~periment 3, 1400C, 30 min. (in Ar) _ . . ..
Comparative Vingl chloride Sample o~ Comparati~e 4 59 E~periment 4 E~p~riment 3, 1600UC, 30 min, (in Ar) _ Comparati~e Vinylidene Temp. increasing rate 856 '~10 Egperiment 5 chloride of 5C/min. t 140C, one hour (in air), lOOO~C, one hour (in Ar) .

-3L~6 5 S~O

_ Intersur- ITrue Utilization Current face dis- densityI 1360/I 1580coefficientefficiency tance, (cm~1/cm-l) (negati~e doo2 (~) (g/cm3) electrote) _ _ 3.45 2.12 0.91 0.11 ~4 _ _ 3.39 2.20 0.09 0 0 _ _ 3.49 1.98 1.22 0.12 95 3.46 2.14 1.03 0.10 91 .
3.39 2.19 0.49 0.06 69 3.46 2.08 0.93 0.09 90 _ , 3.69 2.05 1.87 0.11 67 3.50 1.95 1.19 0.10 92 . _ .45 1.90 1.21 0.04 81 .
3.69 2.02 1.92 0.08 56 .

~2655~0 E2ample 7 and Comparati~e E2periment 6:
The procedure of E~ample 1 ~as faithfullY repeated, e~cept that the binder shown in Table 2 ~as used in the place of the binder used in the acti~e material fDr the negati~e electrode of E~ample 1. The charge stop ~oltage and the o~er~oltage in~olYed in this case are also shown in Table 2.

T a b I e 2 j _ Binder RelatiYe SolYent Charge OYer-dielectric StDp ~oltage 10 ¦ _ l ratio l Ivoltage E~ample 7 Fluorine 13.8 Methylethyl ~3.96 0.05 rubber ketone Comparati~e Butyl 2.38 Toluene 4.80 0.~3 Experiment 6 rubber _ Examples 8 - 10:
The procedure of E~ample 1 was repeated, except that a ~arying electrolyte shDffn in Table 3 ~as used in the place of the solution of 0.6 mol of LiCI04 in propylene carbonate. The results of the battery e~aluation sr~ also shn~n in Table 3.

2~

~ ~ 6 S 5 Ta bl e _ Electrolyte Utilization CurreDt O~Pr-coefficient efficiency Yoltage (negati7e (Z) l electrode) I
5 E~ample 8 0.6N LiBF4/PC* 0.12 97.5 0.04 E~ample 9 O.6M LiC~O4/ethyleneO.12 96.6 O.05 carbonate _ _ Example 10 0.6M LiCQ34/~inylene 0.11 96.8 0.05 carbonate _ _ ~ PC = Propylene carbonate E~ample 11:
A liquid raw material was prepared by dissolYing biscyclopentadienyl iron in a concentration of 1% by weight in benzene.
Inside a tubular furnace pro~ided with a Kanthal wire heater, an alumina furnace core tube 60 mm in inside diameter was installed horizontally, with the opposite ends sealed with rubber plugs. An alumina pipe 6 mm in inside diameter for introducing the liquid raw material was p~ssed through on0 of the two plugs until one end of this pipe re~ched the central part of the furnace tube at the position having a preliminarily measured inner furnace temperature of 510C. The other end of the pipe was pTotruded from the furnace and connected to a meteTing pUlDp with a rubber tube. To the metering pump, the ~655i~0 liquid raw material was fed as pressed uith an ine~t gas. A
pipe Df the same diamPteT was passed through the rubbeT plug on the Tau material inlet side so as to introduce an inert gas for displacement of the air entrapped inside the furnace and hydrogen gas for aiding in the grouth of fibers through the medium of a rubber tube. These two gases were freely switchable by means of a ~al~e. In the rubber plug on the other end, an alumina pipe 6 mm in inside diameter ~as laid so as to release the waste gas through the medium of a rubber tube.
First, the air entrapped in the furnace was displaced with an inert gas. After the disPlacement, the inert gas was switched to hgdrogen gas and the furnace was heated u~til the temperature at the furnace center reached 1200C. At this time, the temperatuTe at the outlet of the pipe was 500C. The lS supply of the hydrogen gas uas continued at a flow rate of 1,000 cc/min and, at the same time, the liquid rau material ~as supplied at a rate of 1 cc/min for about 15 minutes. As the result, 7.1 g of carbon fibers were obtained in the zone of 600 to 1,200C. The a~erage diameter, the BET surface area, the true densitY, the intersurface distance, doo2, based on the X-ra~ diffractinn, and Lc~002~ of the carbon fibers ~ere respecti~ely about 4 ~, 9 m2/g~ 2.03 g/cm3, 3.54 ~, and 38 ~.
The amount 5 mg of the carbon fibers of the ~apor-phase growth were molded in the form of a sheet 1 cm ~ 5 cm of area. The sheet uas nipped betueen SUS nets to form a negati~e electrode ~OT a battery shown in Fig. 1.
Separately, a positi~e electrDde was prepared by molding ~cOn2 in the form of a sheet 1 cm ~ 5 rm ~ 0.1 cm and nipping the sheet between SUS nets. A battery produced by using the electrodes mentioned aboYe and a solution of 0.~ M LiCI04 in propylene carbonate as an electrolyte was e~aluated.
A nonuo~en fabric Df polypropylene was used as a separator.
When this battery was charged at a constant cuTTent of 2 10 mA for 50 minutes, it showed an open terminal ~oltage of ~.9 V. BY this charging, the proportion of Li~ ion re~ersibly taken in per carbon atom, namely the utilization coefficient, was 0.15. Thereaftet, a chaTging-discharging cycle (charge stop voltage 3.95 V and discharge stop ~oltage 2,70 Y) was Tepeated at a constant curre~t of 2 mA. The changes of current efficiency and utilization coefficient during the succession of cycles were as shown in Fig. 4-A. The energY density (per active mateTial for negati~e electrode) in the 5th cycle was 1139 Whr/kg. This battery, after 720 hours' standing, showed a self-discharge ratio of 7X.
Esamples 12 - 15 and Comparative Experiments 7 - 8:
In an atmosphere of Ar, the carbon fibers of the ~apor-phase grouth obtained in Esample 11 were treated at a ~arying temperature shown in Table 4 for 30 minutes. Batteries 25 produced were e~aluated by following the procedure of ~sample ~ Z 6 ~

11. The data obtained in this test concerning the current efficiency and the utilization coefficîent, i.e. the amount of Li~ ion taken in reYersibly per carbon atom, uere as shown in TablP 4. This table also shows the data concerning the ~T
surface area, the true densitY, and the Lc(002) based o~ the X-ray diffraction, of the samples after the heat treatment.

4 O

~265S~

--I =o ~o ~ ~o ~ .1,. ~ I , ~
._ _ .
e~E~ ~ ~0 O ~ ~ CD
E-- 'O _ N N N N N l . ____ d ~ Ir~ Ir~ o~ N O~
_~ _ ____I

q~ ~ o~ c~ el~ C~ C~ N
_ __ I
a~ ~ CD Ir~ O~ O
o~tl a~ c_ cl~ c7~ _ I ~ _ l _ I I
.0 1' o-:C c~ U~ 0 ~_ ~ CD
E- ~ ~ ~1 ~ C~ C~ C~) ~ ~ _ _ _ r--I
~ rO ~ _ _ X _ O O
,~ o o o o o - - - -~ o o o o o o ~ _ _ _~ _ N N
I _ _ _ _, _ I a~ ~ I
N ~1 ~ Lt~ 1~ ~ Il~ ~
_~ _ _ _~ _ ~ _ ~ ~ ~ ~ E~.!
I L~ ~ ~ ~ ~ ~ l ~ ~ 6 5 E~ample 16:
The carbon fibers of the ~apor-phase growth obtained in E2ample 11 uere comminuted in a ball mill tD obtain crushed carbon fibers of the ~apDr-phase grouth haYing an a~erage particle diameter of 4 ~. A mi~ture of 9 parts by weight oî
the crushed carbon fibers with 1 part by weight of powdered polyethylene was molded on a SUS net under pressure of 250 kg/cm2 to obtain a test piece in the form Df a sheet l cm ~ 5 cm in area.
A 'oattery using this test piece as a negati~e electrode was tested by following the procedure of F~ample 1. The results are shown in Eig. 4-B.
Example 17:
A liquid raw material was prepared by dissolYing biscyclopentadienyl iron in a concentration of lX by weight in benzene.
Inside a tubular furnace proYided with a Kanthal Nire heater, an alumina furnace core tube 60 mm in inside diameter was installed horizontallY, with the opposite ends sealed with rubber plugs. An alumina pipe 6 mm in inside diameter for introducing the liquid rau material WAS passed through one of the two plugs until one end of this pipe reached the central part of the furnace tube at the position ha~ing a preliminarilY
measured inner furnace temperature of 510C. The other end of the pipe was ProtJuded from the furnac0 and connected to a ~2655~

metering pump with a rubbet tube. To the metering pump, the liquid raw material was fed as pressed with an ineTt ga~. A
pipe of the same diameter was passed through the rubber plug on the raw material inlet side so as to introduce an ine7t gas for disPlacement of the air entrapped inside the furnace and hydrogen gas for aiding in the growth of fibers through the medium of a rubber tube. These two gases were freel~
switchable by means of a ~al~e. ID the rubber plug on the other end, an alumina pipe 6 mm in inside diameter uas laid SD
as to release the waste gas through the medium of a rubber tube.
Eirst, the air entrapped in the furnace was disp]aced with an inert gas. After the displacement, the insert gas uas switched to hYdrogen gas and the furnace was heated until the temperature at the furnace center reached 1200C. At this time, the temperature at the outlet of the pipe was 500C. The supply of the hydrogen gas was continued at a flow rate of 2,500 cc/min and, at the same time, the liquid raw material was supplied at a rate of 2.5 cc/min for three minutes. As the result, 3.7 g of carbon fibers were obtained in the zone of 600 to 1,200C. ~he average diameter, the BET surface area, the true density, ~nd Lc~002) b~sed on the X-ray di~r~ction of the carbon fibers were respecti~elY 0.2 ~, 16 m2/g~ 2.04 g/cm3, and 45 A. A battery using these carbon fibers of the ~apor-phase growth uas e~aluated by following the procedure of E~ample 11. The terminal ~oltage was ~.9 V and the prDportion ~655~30 Df Li~ ion taken in, namely the utilization coefficient, ~as 0.14 per carbon atom. The current efficiency was 83g.
Comparati~e E~periment g:
The pTDcedure of E~ample 16 was faithfull~ ~epeated, e~cept that commerciallY available graphite powder (a product of Lonza SpA ha~ing a BET N2 specific surface area of 22 m2/g~
a true densitY of 2~25 g/cm3, and an intersurface distance, doo2, of 3.36 A, and Lc(002) of greater than 1,000 B, mar~eted under trademark designation of "Lonza Graphite KS 2.5~) was used in the place of the crushed carbon fibers of the vapor-phase growth. Although the battery was charged at a constant current of 2 mA for one hour, it was incapable of discharging. The proportion of Li~ ion taken in reversibly was 0.
Comparative E~petiment 10:
The procedure of E~ample 11 was faithfully repeated, e~cept that commercially available acti~ated carbon fibers thaving a BET N2 specific surface area of 450 m2/g1 a true densitY of 1.70 g/cm3, an intersurface distance, doo2, of 3.60 ~, and Lc(002) of less than 10 ~) were used in the place of the carbon fibers of the vapor-phase growth.
The changes of current efficiency and utilization coefficient involved in this case are as shown in ~ig. 4-C.
The energy densitY tper active material for negative electrode~
in the 5th cycle was 228 Whr/kg.

: , ~2~i55~30 The battery, after 720 hDu~s' standing at 25C, shDwed a self-discharge ratio of 85%.
E~ample 18:
In the air, polyacrylonitrile fibeTs weTe treated at 230C f OT one hour and then in an atmo~pheTe Df Ar, heated at 1,000C foT one hour. The BET surface aTea, the true densitY, the intersurface distance, doo2, based on the X-ray diffraction, and the Lc(002) of the carbonaceous material consequentl~ obtained were respecti~elg 0.6 m2/g, 1.75 g/cm3, 3.60 A, and 20 ~.
The amount 5 mg of the carbonaceous material was molded in the form of a sheet 1 cm ~ 5 cm in area. This sheet was nipped between SUS nets to produce a negati~e electrode for a battery shown in Fig. 1.
Separately, a mi~ture consisting of 1.04 mols of lithium carbonate, 1.86 mols of cobalt oxide, and 0.10 mol of stannic o~ide was calcined at 650C foT fi~e hours and then fired in the air at 850C for 12 hours. ConsequentlY, there was obtained a composite 02ide ha~ing a composition of Lil 02Coo g3Sno 0502. This composite o~ide was comminuted iD a ball mill into purticles of an ~erc~e siz0 of 3 ~m~ Then, 1 part by weight of the composite oxide was mi~ed with 0.05 part by weight of graphite, 0.05 part by weight of acetylene black, and l part by weight of a solution of polyqinylidene fluoride trelati~e dielectTic ratio 8.43~ in dimethyl formamide (2 wt% in ~ 2 6 S ~ ~ O

concentration). The resulting mi~ture was applied in a thickness of 100 ~m on one surface, 1 cm x 5 cm, of an alumina foil 15 ~m in thicknPss. The coated alumina foil was nipped between SUS nets to prDduce a positi~e electrode.
A battery using the positi~e electrode and a solution of 0.6M LiCI04 in prnpglene caTbonate as an electrolyte uas e~aluated.
A nonwo~en fabric of polyprDpylene was used as a separatoT .
When the battery uas charged at a constant cuTTent of 2 mA for 50 minutes, it showed an open terminal ~oltage of 3.9 V. By the charging, the pToportion of Li~ ion taken in per caTbon atom, namely the utilization coefficient, was 0.17.
Thereafter, a charging-discharging cycle (chaTge stop ~oltage 3.95 Y and discharge stop voltage 2.7 Y) at a constant cuTrent of 2 mA was repeated. The changes of current efficiencY and utilization coefficient during the succession of cycles were as shown in Fig. 5-A. The energy densitY (per active material for negati~e electrode) in the 5th cycle was 1292 Whr/kg. The o~er~oltage was 0.04 V.
The batter~, aft~r 720 hours' stunding ut 25-C, showed self-discharge ratio o~ 8X.
E~amples 19 - 22 and Comparati~e E~periments 11 - 13:
The carbonaceous material obtained by firin~ in E~ample 2~ 18 was treated ;D an atmosphere of Ar at a ~arying temperature ~6~i5~30 shown in Table 5. The battery consequentl~ ptoduced was e~aluated b~ following the procedure of E~ample 1.
The data Dbtained in the test concetning the current efficiency and the proportion of Li~ ion taken in reversibl~
per carbon atom, namely the utilization coefficie~t, are as shown in Table 5~
This table also shows the data concerning the intersurface distance, doo2, based on the X-ray di~fraction, the Lc(002)~ the BET surface area, and the tTue densitY.

~2655~30 _ _ ~ C~ _ O _ O O O N
_ _ _ ~ ~ N L;':l 1~ 1~ LL~ ~-- _ CU-cq E3 ~_ C_ ~_ ~_ ~_ t o, ~ ~ a, _ _ _ _ _ _ _

5'~ 1- " ~C. cc e 1-~-C~ O N el' O _ U~
o~: _ N N N C~ ~ e~
_~ _ _ _ ~ ~ ~ In ~ O~ a~ ~
l_ ~ _ Ln U~ U~ el' ~ ~ ~
u~ ~ ~: c~ ;~ ~ ~ r~
C~o ~:_ __ _ C .~ ~ o~ _ a~ _. _ ~ _ ~ ~0 O~ U~ ~ C'~ ~ _ ~ - -8~ ~ _ ~ _ _ ~o o .~ 4 o o o o o o o ._ _ .

F! R ~:1 ~:1 r~ C::l ~.a C:~ ~
~ c~ $ g~ g~ q~ ~ O
_ _ _ _ r~l e~l c~
_ _ C~l C~
~ O _ ~I ~ ~ ~ ~ ~ ~
_ C~l ~I N ~ ~ , _ ~ ~ R
a~ a.l ~! ." ~ ~! .'' ~o~
~ ~ ~ ~ c~l~ e~ c ~2655~30 E~ample 23:
In the air, powdered polyacrylonitrile was heated at 240C for one hour and then, in an atmosphere of Ar, heated at 1,250C for o~e hDur. The BET surface area, the true density, the ~alue of doo2 based on the X-ray diffraction, and the ~alue of Lc(002) of the carbonaceous powder were respectively 9 m2Jg, 1.80 g/cm3, 3.56 ~, and 20 ~. The powder had an a~erage particle diameter of 3 ~. A mi~ture of 1 part by weight of this powder with 1 part by weight of a solution of polyacrylonitrile (in a concentration of 4% by weight) in dimethyl formamide was applied in a thickness of 75 ~m on one surface, 1 cm x 5 cm in area, of nickel foil 50 ~m in thickness. The coated nickel foil was nipped between SUS nets to produce a negati~e electrode. A battery using this negative electrode was tested fot batteTy properties by faithfully following the procedure of E~ample 18. The results are as shown in Eig. 5-B.
E~ample 24:
In an atmosphere of Ar, asphalt pitch of room 20 tempeTatUre WAS heated at a tempeTature increasing rate o~
10C/~in, held at 530-C for one hour, and fiTed ~or carbonization at 1,150C for one hour. The BET surface area, the true density, the intersurface distance, doo2, based on the X-ray diffraction, and the ~alue of Lc002 of the consequently ptoduced carbonaceous matetial were respecti~ely 47 m2/g, 2.00 ~ ~ 6 ~ S ~ 0 gJcm3, 3.48 ~, and 26 ~. This caTbonaceous material was comminuted in a ba]l mill into particles of an average diameter of 1.5 ~m. The prDcedure D~ E~ample 1 was faithfully ~epea~ed, egcept that this powder was used in the place of the pDude~ed caTbonization product of anthracene oil. The results of the battery e~aluation are as shown in Fig. 6-A.
The energy densitY (per acti~e material for negati~e electTDde) in the 5th cycle was 121.6 Whr/kg. This battery, after 720 hours' standing at 25C, showed a self-discharge ratio of 7%.
E~amples 25 - 32 and Comparati~e E~periments 14 - 17:
A carbonaceous material was obtained by subjecting a ~arying grade of pitch indicated in Table 6 tc carbonization by firing under a ~arying set of conditions indicated in Table 6.
A battery using this carbonaceous material was e~aluated by following the procedure of E~ample 24. In this test, the current efficiency and the proportion of Li~ ion taken in reversibly per carbon atom, namely the utilization coefficient, were as shown in Table 6. The table also shows the BET surface area, the value of Lc~002) based on the X-ray diffraction, and the true density.
Comparati~e Experiment 18:
The procedure of Example 1 ~as faithfullY repeuted, e~cept that commercially a~ailable acti~ated carbon (having a BET surface area of 450 m2/g, a true densitY of 1.70 g/cm3, an ~2~55~

intersulface distance. doo2, of 3.60 ~, and Lc(002) of less than 10 ~) ~as used in the place of the po~dered carbonization plOdUCt Df anthlaCelle Di I . Tbe changes of current efficie~cy and utilization coefficient in~ol~ed in this case were as shDwn in ~ig. 6-B. The energy density (per acti~e material for negati~e electrode) in the 5th cycle ~as 217 Whr/kg. This battery, after 720 hours~ standing at 25C, shoued a self-discharge ratio of 88%.

. .

~L~6 5~;~3() T a b I e 6 Rau Conditions Df heat treatmeDt BET
material surface pitch Temp. Temp. Temp. of area increasing retained carbuni- (m2/g) rate zation (C/min) _ _ E~ample 25 Asphalt 10 530C 1100~C 12 pitch one hour one hour E2ample 26 ~ 10 580C 1400C 5.9 one houT one hDu _ E~ample 27 ~ 10 530C 1800C 4.1 . Dne hour one hour _ Comparati~e ~ 20 530C 2700C 3.6 E~periment 14 one hour one hour _ Comparati~e ~ 20 530C 3000C 3.2 E~periment 15 one hour one hour Example 28 Crude 10 550C 1150C 11 oil one hous one hour decom-posidion pitch . .
E~ample 29 Crude 10 550C 1400C 6.8 oil one hour one hour decom-posidion pitch Comparati~e 20 550C 2700C 4.2 Experiment 16 ~ one hour one hour .
Ex~mple 30 Coal tar10 460C 1150C 9.1 pitch one hour one hour _ . . _ E~mple 31 ~ 10 460C llOO-C 13 one hour one hour _ Example 32 ~ 10 460C 1500C 5.2 one hour one hour Comparative ~ 100 _ 1100C 61 25 E~periment 18 one hour .

~65~;!30 Lc(002) IntersuTface True R IUtilization Current (~)distance densit~ I 1360/I 1580 coefficient efficiency doo2 (~) (g~cn~) (cmrl/cmr~) ~negati~e (%) electTode) _ 20 3.49 1 98 1.08 0.17 98 9 44 3.47 2.11 0.96 0.15 99.3 66 3.44 2.~5 0.78 - 0.080 ~5.1 .
190 3.41 2.17 0.12 0.021 27.1 260 3.39 2.20 0.08 0 0 . , 3.48 1.99 0.99 0.16 98.1 . _ 3.47 2.10 0.83 0.10 99.5 . _ 200 3.40 2.18 0.09 0.017 11.3 . _ 27 3.49 2.01 1.07 0.15 98.2 . _ _ _ 3.51 1.95 1.12 O.lB 97.B
. . ~ _ . .
46 3.~5 2.13 0.89 0.10 99.4 .
3.5~ 1.70 1.27 0.060 89.7 . __ .

... .. . .
, 1 ~ 6 5 E~ample 33:
In aD atmosphere of Ar, raw coke of pertDleum origin was heated from room temperature at a temperature increasing rate of 10C/min and carbonized by firing at 1,400C for 0.5 hour~
The BET surface area, the true densitY, the intersurface distance, doo2, based on the X-ray diffraction, and the value of Lc(002) of the carbonaceous material consequently produced were respecti~ely 16 m2/g, 2.13 g/cm3, 3.46 ~, and 46 ~. This carbonaceous material was comminuted in a ball mill into powder having an average particle diameter of 5 ~m. The procedure of E~ample 1 was faithfully repeated, e~cept that this powder was used in the place of the powdered carbonization product of anthracene oil. The results are as shown in Eig. 7-A. The energy densitY tper acti~e material for negati~e electrode) in the 5th cycle was 911 Whr/kg. The battery, after 720 hours' standing at 25C, showed a self-dischaTge Tatio of 7Z.
E~amples 34 - 35 and Comparative E~periments 19 - 20:
A carbonaceous material was prepaTed by subjecting a ~arying grade of rau coke indicated in Table 7 to carbonization by firing under a ~arying set of conditions indicated in Table 7. A battery using the carbonaceous muterial was e~luated by follouing the procedure of Example 33. The results are shown in Table 7. This table also shous the data concerning the BET
surface area, the true densitY, the intersurface distance, d(oo2)~ based on the X-ray diffraction, ~nd the ~alue of Lc(002).

~265S~3~
. . __ _ C~ ~ U~ U~
. _ _ . ._ D O _ _ ~ g o o o o C~, o:, ~0 IC= i C~ _ O
. _ ~ ~ C~ ~. C~
~ := ~ ~
~ ~ ~ C~ C'~
r- _ ~_ ' r- ~ ~ CD
~ C~l C`J N N
E- E~
o ~o c~ o "~ ~ I Y~n ~ I ~
._ E-- ~3 N O O O O
._ j Yi' ,, _ _ 9 ~ ~ ~o _ _ o o , - ___ . - _ __ o ~ 8 ~ o R O X
x ~! o o ~ o ~o ~! o o ----` i~.e. _~

~265~0 E~ample 36:
In a ball mill~ commerciallg a~ailable needle c~ke of pe~rDleum Drigin ~prDduc~ of KDa Oil Co., Ltd. marketed undel trademaTk designation Df ~KOA-SJ CDke~) was comminuted into particles of an average diameter of 10 ~m. The procedure of E~ample I was faithfully repeated, egcept that the Po~der consequently obtained was used in the place Df the powdered carbonization product of anthracene Di I . The results are as shoun in Fig. 7-B.
The BET surface area, the true densitY, the intersurface distance, doo2, based on the X-ra~ diffraction, and the ~alue of ~c(002) of the needle coke were respecti~ely 11 m2/g, 2.13 g/cm3, 3.44 ~, and 52 A.
E~amples 37 - 40:
The procedure of E~ample 36 uas repeated, e~cept that a ~arying grade of coke indicated in Table 8 was used in the place of the needle coke of petroleum origin (ptoduct of Koa Oil Co., Ltd. marketed under trademark designatioD of ~KOA
SJ-Coker). The BET surface area, the true densitY, the intersurface distance, doo2, based on the X-ray di~fraction, and the ~alue of Lc~002) obtained as tha result are as shown in Table 8.

~65 I ~ ,, o ~ o~ ~ ~
h ~ a~ 0~ ~o ~
~ ~ ~ a~ o~

~0 ~ _ g ~ ~ N
1~1 O-rl O ~ rl N rl J~ .
~0 O O O O
po~D _ _ O
U~.
.1 1 H U O C~ ~ O
~: ~ O
H _ _ .
o,¢ ~ N
U
~ 0--~ ~D ~O U~ q~
~3 ~ ~1 ~ N ~ ~ ~ ~
E1~ 11 cq o . -H ~ ~ ~ ~ ~ ~ ~
p~'_ ~1 ~1 ~1 O
~ 3 N ~1 N N

~ --E~ ~ In u~ c~
rl ~o ~0' ~0 O

O ~I R O R ~ ~) ~ ~ 'I:l~l-tr ~ .CI
IC ~ ~ o-~
e~ Z ~40 Z U O :~; U O . P' t~ ~O ~ o~
~ ~ ~ ll 12~i55~

E~ample 41 and Comparative E~perimeDts 21 - 27:
The procedure of E~ample 1 was faithfull~ repeated, e~cept that a varying carbonaceous material indicated in Table 9 was used in the place of the powdered carbonizatiDn product 5 of anthracene oil. The BET surface area, the true density, the intersurface distance, doo2, based on the X-ray diffraction, and the ~alue of Lc(002) are as shown in Table 9.

2~

~6S5~

Table 9 Carbon- Treatment BET True aceous surface density material are2a (g/cm3) Example 41 Furnace 8 1.85 black Comparative Furnace 525 1.85 Experiment 21 black Comparative Channel 742 1.85 Experiment 22 black Comparative Acetylene 61 1.95 Experiment 23 black Comparative Carbon 850 2.20 Experiment 24 black _ Comparative Pitch type Comminut-66 1.65 Experiment 25 carbon ing in fiber ball mill Comparative Pitch type Comminut-58 1.57 Experiment 26 carbon ing in fiber ball mill _ Comparative Glassy Comminut- 90 1.70 Experiment 27 carbon ing in ball mill 3L~6s~

InteT- lLc(oo2) Utilization Current surface (~)I 1360/I 1580cuefficient efficie~c~
distance, (cm-l/cm-l) (negati~e (X) doo2 (~ electrode) _ _ 3.67 17 1.46 0.1~ 97.8 _ _ 3.69 17 1.19 0.01 61 _ 3.69 16 1.33 _ _ 51 _ 3.48 47 0.87 0.07 72 __ 3.42 C 10 0.84 0.04 16 _ 3.62 lS 1.26 0.12 77 _ _ 3.50 17 1.01 0.10 82 _ 3.45 39 1.93 0.02 67

6 O

~ ~ 6 5 $

E~ample 42:
A mj~ tUT e consisting of 1.05 mols Df lithium carbonate, 1.90 mols of cDbalt o~ide, aDd 0.084 mDl of stannic o~ide was calcinated at 650C for fi~e hours and then, in the air, fired at 850C for 12 hours. Consequentl~, there was obtaiDed a composite o~ide ha~ing a composition of Lil 03CoO. 95SllO. 04702.
This co~posite o~ide was comminuted in a ball mill into particles of an a~erage diameter of 3 ~m. Then 1 part by weight of this composite o~ide was mi~ed with 1 part by weight of a solution of po]Yacrylonitrile (concentration 2X by weight) in dimethYI formamide and 0.2 part by weight of graphite as an electroconducting aid. The resulting mi~ture was applied in a thickness nf 75 ~m on one surface, 1 cm x 5 cm, of an aluminum foil 15 ~m in thickness.
A battery shown in Fig. 1 was produced by using the coated aluminum foil as a positi~e electrode, a lithium piece as a negati~e electrode, and a solution of 0.6M LiCI04 in propylene carbonate as an electrolyte.
This battery was charged at a constant current of 25 mA
tcurrent densitY 5 mA/cm2) for 30 minutes and then discharged at the same constant current ot 25 mA until ~.8 Y. The charging ~olta$e and the discharging ~oltage in~ol~ed in this case are as shown in Fig. 8. The o~er~oltage was extremely small.
Thereafter, a charging-discharging cycle WBS repeated.

~65~;~0 The charging voltage and the discharging voltage in the 500th cycle a.e as shown in Fig. 9, indicating that the ~oltages were not substantially changed.
E~amples 43 - 44 and Comparati~e E~periments 29 - 31:
The procedure Df E~ample 42 was repeated, e~cept that the amounts of lithium carbonate, cobalt o~ide, and stannic 02ide were ~aried as shown in Table 10. Consequently, ~arious composite o~ides were obtained. TheiT percentage compositions are also sho~n in Table 10.

T a b I e 10 _ Starting CompositioD Composition of composite o~ide Lithium Cobalt Stannic carbonate 02 i de oxide (mol) (mol) (mol) 15 E~ample 43 1.03 1.77 9.14 Lil olCoo 88SnO. 0702 E~ample 44 1.06 1.98 0.02 Lil 03CoO. 99Sno, 0102 Comparati~e 1.03 2.02 0 Lil ooCol 0102 E~periment 29 Comparati~e 1.15 1.92 0.22 Li~ ~ICoo 96SnO. 1102 Experiment 30 Comparati~e 1.06 2.19 0.06 ~il 03Col osSno.0302 E~periment 31 _ _ _ Batteries using these composite o~ides were e~aluated by ~ollowing the procedure of Egample 1. The data concerning the ~26S5~0 charge stop ~oltage, the open terminal Yoltage, and the overvoltage are shown in Table 11.

T a b I e l 1 _ _ _ _ Charge stop ~pen terminal OYervoltage qoltage Poltage E~ample 43 4.28 4.22 0.06 . _ _ _ Esample 44 4.31 4.23 0.08 Comparati~e 4.53 4.20 0.33 E~periment 29 10 Comparati~e 4.43 4.21 0.22 E~periment 30 _ Comparati~e 4.51 4.21 0.30 IE~periment 31 15 Example 45:
The procedure of E~ample 42 was faithfully repeated, e~cept that 0.041 mol of indium ogide uas used in the place of 0.082 mol of stannîc oxide. A battery using the resulting carbonaceous material was evaluated similarly. The overvoltage of this battery is as shown in Table 12.
Example 46:
The procedure of Egumple 42 was faithfully repeated, egcept that 0.042 mol of aluminum oride was used in the place of 0.084 mol of stannic oxide. A battery using the resulting carbonacenus material was e~aluated. The over~oltage of this ~655~0 battery is as shown in Table 12.
E~ample 47:
The prDcedure of Egample 42 was faithfull~ repeated, e~cept that 1.90 mols of nickel o~ide was used in the place of 1.90 mols Df cobalt ogide. A battery using the resulting carbonaceous material was eva]uated. The over~oltage of this battery is as shown in Table 12.

T a b l e 1 2 _ Composition of Overvoltage composite ogide _ _ Egample 45 Lil.olCoo. 9 5 Ino.o 4 n2 n .05 E~ample 46 Li~.02Coo.s6AQo 04O2 0.06 Egample 47 Lil. 05~io. 96Sno. 042 0.09 Egample 48 and Comparative E~periment 32:
The procedure o~ E~ample 42 was repeated faithfully e2cept that a varying electroconducting aid indicated in Table 13 was u~ed in the place of 0.2 part bg weight Df graphite.
The overvoltage determined b~ the test is shown in Table 13.

~655~3~

Tab I e 13 _ _ Electroconducting aid O~enoltage E~ample 48 0.075 part by 0.025 part by O.û3 weight of weight of graphite acetylene (a~erage paJticle ~ black diameter 5,L) (a~erage particle diameter 0. 03~L) Comparative None 0.40 E~per iment 82 Examples 49 - 53 and Comparati~e E~periments 33 - 38:
The procedure of E~ample 42 was faithful Iy repeated for e~aluation of batteries e~cept that a ~arying solution of binder indicated in Table 14 was used in the place of the 15 solution of polyacrylonitrile in dimethYI formamide. The resul ts determined are as shown in Tabl e 14 .

~i55~3Q

T a b l e 1 4 Binder Relative Solvent OPer-dielect,ic vDltage ratlo E~ample 49 Nitrile rubber 17.3 Methyl ethyl 0.03V
ketone E~ample 50 Polyvinylidene 8.43 DimethylfoTmamide 0.04Y
fluoride _ E2ample 51 PDlgchlDTopreDe 6.53 TetrahydrofuTan 0.07V
_ E~ample 52 Polyvinylidene 5.51 Tetrahydrnfuran 0.08V
chloride _ _ E~ample 53 Nitrocellulose 7.51 Ethyl acetate 0.07V
Comparative Polybutadiene 2.51 Toluene 0.83V
Experiment 33 .
CompaTative Polyisoprene 2.37 Toluene 0.75V
E~periment 34 _ Comparative But~l TubbeT 2.38 Toluene 0.91V
E~periment 35 Comparative PolymethYI 3.03 Methylethyl 0.31V
Erperiment 36 methacTylate ketane Comparative Polystvrene 2.51 Toluene 0.88V
E~periment 37 __ _ Comparative Styren~/buta- 2.53 Toluene 0.69V
Erperiment ~8 diene rubbsr i I

~26S5~

E~ample 54:
A battery was produced bg faithfull~ following the procedure of E~ample 42, egcept that lithium-aluminum alloy was used in the place of lithium. The battery was charged at a constant curJent of 10 mA (current densit~ 2 mA/cm2) for 150 minutes (charge stop voltage 3.70 V) and then discharged at the same constant ~oltage until 3.55 V. The over~oltage was 0.02 V.
E~ample 55:
A battery was produced bg faithfully following the procedure of E~ample 42, except that Wood's metal (bismuth-tin-lead-cadmium alloy) was used in the place of lithium. The batterg was charged at a constant current of 10 mA (current densitg 2 mA/cm2) for 150 minutes (charge stop ~oltage 3.75 V) and then discharged at the same constant voltage until 3.55 Y. The o~er~oltage was 0.02 V.

Claims (20)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A secondary battery comprising positive and negative electrodes, a separator, and a nonaqueous electrolyte, wherein said secondary battery is characterized by having as an active material for said positive electrode a material as indicated in I below and for said negative electrode a material as indicated in II
below;
I : a non-carbonaceous active material, and II : a carbonaceous material which has a BET-method specific surface area, A(m2/g), being in the range of 0.1<A <100 and a crystal thickness, Lc(.ANG.), based on X-ray diffraction and a true density, ?(g/cm3), which satisfies the conditions, 1.80< ? <2.18, 15< Lc and 120 ?-227<Lc<120 ?-189.

2. A secondary battery comprising positive and negative electrodes, a separator, and a nonaqueous electrolyte, wherein said secondary battery is characterized by having as an active material for said positive electrode a material as indicated in I below:
I : a composite oxide possessing a layer structure and represented by the general formula:
AxMyNzO2 wherein A is at least one member selected from the group consisting of alkali metals, M is a transition metal, N is at least one member selected from the group consisting of Al, In, and Sn, and x, y, and z satisfy the expression 0.05< x ?1.10, 0.85?y ?1.00, and 0.001 ?z ?0.10, respectively.

3. A secondary battery according to claim 1, wherein the positive electrode is a composite oxide possessing a layer structure and represented by the general formula:
AxMyNzO2 wherein A is at least one member selected from the group consisting of alkali metals, M is a transition metal, N is at least one member selected from the group consisting of Al, In, and Sn, and x, y, and z satisfy the expression, 0.05? x ?1.10, 0.85?y ?1.00, and 0.001 ?z ?0.10, respectively.

4. A secondary battery according to claim 2, wherein said A is lithium.

5. A secondary battery according to claim 2, wherein said M is at least one member selected from the group consisting of Ni and Co.

6. A secondary battery according to claim 2, wherein said N is Sn.

7. A secondary battery according to claim 3, wherein the carbonaceous material is carbon fibers of the vaporphase growth method and/or the comminuted product thereof.

8. A secondary battery according to claim 3, wherein the carbonaceous material is a fired carbonization product of a pitch.

9. A secondary battery according to claim 3, wherein the carbonaceous material is needle coke.

10. A secondary battery according to claim 1, 2 or 3, wherein the or each active material is formed by using an organic polymer dissolved and/or dispersed in a solvent as a binder.

11. A secondary battery according to claim 1, 2 or 3, wherein the or each active material is formed by using an organic polymer dissolved and/or dispersed in a solvent as a binder, said polymer having a specific dielectric constant greater than 4.5 at 25°C and 1 KHz of frequency.

12. A secondary battery according to claim 1, 2 or 3, wherein the or each active material is formed using an organic polymer dissolved and/or dispersed in a solvent as a binder, said organic polymer being at least one polymer or copolymer of a monomer selected from the group consisting of acrylonitrile, methacrylonitrile, vinyl fluoride, and vinylidene fluoride.

13. A secondary battery according to claim 1, 2 or 3, wherein the separator is a polyolefin type microporous membrane.

14. A secondary battery according to claim 1, 2 or 3, wherein cyclic carbonate is used as a solvent for the nonaqueous electrolyte.

15. A secondary battery according to claim 1, 2 or 3, wherein a cyclic carbonate which is at least one member selected from the group consisting of propylene carbonate, ethylene carbonate, and vinylene carbonate is used as a solvent for the nonaqueous electrolyte.

16. A secondary battery according to claim 1, wherein either of the positive and negative electrodes includes carbon as an aid conductor in a concentration of 1 to 30 parts by weight based on 100 parts by weight of the composite oxide as the active material.

17. A secondary battery according to claim 2, wherein either of the positive and negative electrodes includes carbon as an aid conductor in a concentration of 1 to 30 parts by weight based on 100 parts by weight of the composite oxide as the active material.

18. A secondary battery according to claim 3, wherein either of the positive and negative electrodes includes carbon as an aid conductor in a concentration of 1 to 30 parts by weight based on 100 parts by weight of the composite oxide as the active material.

19. A secondary battery according to claim 16, 17 or 18, wherein the carbon is at least one member selected from the group consisting of graphite and carbon black.

20. A secondary battery according to claim 16, 17 or 18, wherein the carbon is a mixture of carbon having an average particle diameter of 0.1 ~ 10µ and carbon having an average particle diameter of 0.01 ~ 0.08µ.