CA1190279A

CA1190279A - Battery and methods of making the battery

Info

Publication number: CA1190279A
Application number: CA000409331A
Authority: CA
Inventors: Klaus Brandt; James A.R. Stiles
Original assignee: BRITISH COLUMBIA DEVELOPMENT Corp
Current assignee: BRITISH COLUMBIA DEVELOPMENT Corp
Priority date: 1981-08-13
Filing date: 1982-08-12
Publication date: 1985-07-09
Also published as: GB2105512A; SE8204620D0; IT8222796A0; SE8204620L; GB2105512B; DE3230249C2; DE3230249A1; SE456202B

Abstract

ABSTRACT OF THE DISCLOSURE

The present invention comprises an electrode apparatus, characterized by an electrode which forms a porous, exterior, amalgamated deposit thereon; and means for applying a compressive load to the electrode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of said amalgamated deposit.

Description

,~ ~ 3 ~ ~f~

rrhis inventlon rela-tes to an e~Lectrode apparatus including means for app~Lying a compressive load -to -the electrode and also -to a ba-ttery and methods employing such an elec-trode apparatus.
The number of times tha-t a metal elec-trode for example an alkali me-ta] anode (i.e. the nega-tive elec-trode) of an elec-trolytic cell (battery) can be repeatedly discharged and recharged usually determines the reversibility of the ba-t-tery. Assuming an excess of 10 electrolyte the reversibility (R) is the number of complete charges and discharges (cycles) ob-tainable from a cell and is given by -the produc-t of the number o~
-turnovers (T) achievable for the elec-trode times the ratio (~) of the amount of metal contained in the electrode to the stoichiometric amount of metal required for complete reaction of the opposite electrode (i.e., R = ~ T).
turnover (T) is defined as one comple-te s-tripping (removal) of the metal from the electrode followed by a complete amalgamation (repla-ting) of the metal onto the 20 electrode. In general this process cannot be repeated indefinitely because corrosion or physical isolation of the metal within the electrode struc-ture renders it progressively more and more difficult to s-trip. In some cases the me-tal becomes inaccessible for stripping and becomes elec-trochemically inactive. To compensa-te for the progressive loss of active me-tal available for s-tripping ba-tteries of-ten include more metal in the elec-trode -than is required for complete reaction with the electro-ly-tically active component of the opposite electrode.
30 Thus, the reversibili-ty is generally a function of the method of stripping and repla-ting the quantity of me-tal available in -the electrode and the quantity of electroly-te available.
For exampLe with free-standing (unpressurized) lithium elec-trodes a ba-t-tery has a maximum of between about 1.6-2.5 turnovers using electrolytes consisting of 1 M LiAsF6 or 1 M LiC10~ in proplyene carbonate. I-t would be highly desirable -to be able -to increase the reversi-bility of such elec-trodes and ba-tteries.

It has now been foun(l-that in accordance with the present inven-tion a signiFicant increase in the number of -turnovers can be achieved for electrodes which form porous, exterior amalgamated deposits -thereon. The present inven-tion provides an elec-trode appara-tus comprising an electrode comprising an alkali me-tal which forms such a porous, exterior, amalgamated deposi- -thereon, and means for applying a compressive load o -the elec-trode such that the deposit, when formed, is compressed so as -to enhance stripping from the ou-ter surEace of said amalgama-ted deposit. The invention also provides a battery comprising a ca-thode, an anode comprising an alkali me-tal, an electrolyte, wherein said anode forms such a porous, exterior, amalgamated deposit thereon, and means for applying a compressive load -to the anode such -that the deposit, when formed, is com?ressed so as to enhance s-tripping from the outer surEace of said amalgamated deposi-t. As indicated, the e~lectrode may be an alkali me-tal anode, e.g., a lithium anode. Also, the compressive load is preferably applied continlously a-t leas-t during recharging.
The present invention further provides a method of making a battery and a method Eor operating a ba-ttery -to increase i-ts reversibili-ty by increasing the number of turnovers available within an electrode of the cell. The method of making the battery includes -the step oE
constructing an electrolytic cell having a ca-thode t an anode, and an elec-trolyte, wherein said anode comprising an alkali metal forms such a porous, e~terior, amalgamated deposi-t -thereon. A compressive load is applied -to such anode as described above. Again, -the electrode is preferably an alkali rnetal anode, e.g., a lithium anode, and -the compressive load is preferably applied -to -the elec-trode continuously during both discharging and recharging.
The elec-trode apparatus, ba-ttery and methods of -the presen-t invention provide a number of distinc-t advantages. The applica-tion of the compressive load forces -the par-ticle or grains of th~ amalgamated deposit on the electrode closer toge-ther. ~s dlscussed ln more detail below, this can also decrease -the elec-trical resistance be-tween the grains and provide for increased resistance to metal ion migration -through -the porous deposit from the grains in question. Thus, by -the presen-t invention, the s-tripping of metal from the ou-ter surface of -the elec-trode (i.e., from the fron-t of the deposi-t) is enhanced~
In one embodimen-t of the invention, the electro-lytic cell (bat-tery) comprises at least one cathode, an 10 alkali metal anode, at least one separator deposed be-tween the anode and cathode, a nonaqueous electrolyte, a~d a means for applying a compressive load which exceeds the compressive streng-th of the amalgamated deposit on the anode i.e.~ the compressive load is such that it deforms the deposit to push the deposit grains closer together and decrease the porosity of the deposit and decrease the electrical resistance between the grains of the deposit.
Preferably, the load exceeds the compressive strength of the substrate on which the deposit is plated, i.e., the 20 compressive load is suff`icien-t to physically deform the substrate. As modeled, this load enhances stripping of alkali metal from the elec-trolytic alkali me-tal grains at the front of the amalgamated deposi-t (between the anode and the separator) with the result -that the reversibility of the battery is increased significantly. Methods of making the battery of this invention are also disclosedO
~ 'he present invention provides particularly advantageous results with lithium electrodes. At a critical pressure, above which the lithium electrode will 30 deform, a plating morphology drastically different from that forrned a-t low pressures :is obtained. Plating deposits obtained with lithium at low pressure, as observed under a scanning electron microscope, are very porous in nature, with grains in the form of loose platlets or thin, join-ted broad-like grains. Plating deposits obtained above -the critical pressure are substan-tially nonporous in nature.
The grains are regular columns with their axes aligned perpenclicular to -the surface of -the subs-trate. The columns are close packed with respect to one another, so -that -the ends of the columns form a nonporous, smooth surface parallel to the substrate surface. Thls type of deposi-t can be maintained over many successive d:issolu-tion and pla-ting [discharqe and charqe] cycles. I-t has been observed in special cases, where the pressure varies across a lithium elec-trode, -that a sharp boundary exists between porous types of deposits and the smooth, columnar type of deposit. This S}lOWS that -the pla-ting morphology is sharply dependen-t on the pressure near -the cri-tical pressure.
In another preferred embodimen-t, -the ca-thode is one which provides a uniform current densi-ty, e.g., a MoS2 cathode and the anode is an alkali metal having an alkali metal subs-trate in-terior and an amalgama-ted deposi-t ex-terior comprising elec-trolytic, alkali metal grains having individual passivation films (preferably formed by replating alkali me-tal on the anode). In one such preferred embodimen-t, the cathode is a transition metal chalcogenide con-taining LixMoS2 and -the anode is lithium.
The quantity x represen-ts the concentra-tion of li-thium in the cathode which increases as lithium ca-tions in-tercalate into the ca-thode during bat-tery discharge as described in detail in U.S. Patent No. 4,224,390. Generally speaking, the value of x will vary in -the range 0 < x ~ 3, with the actual value depending upon the particular phase in which -the cell is operated~ Preferably the LixMoS2 cathode-ac-tive material is preconditioned -to operating in "Phase Ir" again as described in U.S. Pa-tent No. 4,224,390.
In order tha-t embodiments of the inven-tion may be fully understood, it will now be described wi-th reference to the accompanying drawings, in wilich:
Figure 1 is a schematic of a battery in accordance with the inven-tion.

- 5a -Figure 2 is a schemcltic of a spiral ba-t-tery in accordance wi-th the invention.
Figure 3 is a schema-tic of -the winding operation for a spiral bat-tery.
~ er-tain electrode materials such as alkali metals, e.g., lithium, are thermodynamica]ly unstable in the presence of metal ion-conducting elec-troly-tes -tha-t are liqulds at ambient -tempera-ture. For example, aqueous electroly-tes react violen-tly with alkali metals to form alkali hydroxides and hydrogen gas. Often, this reaction is so violen-t as to be explosive. Some electrolytes, however, react less violen-tly wi-th electrode metals to form kinetically stable passivation films on the surface of -the me-tal elec-trode. These latter electrolytes can be used -to cons-truct practical cells that use metal electrodes.
10For example, after cycling such a metal electroly-tic cell, two portions of -the electrode are physically isolatable. They are (1) a central, essentially nonporous, metal substra~e having a passivation film and

(2) a porous, pla-ted, amalgamated deposit of electroly-tically active metallic grains, wherein each grain has a passivation film.
Wherever such a me-tal electrode is exposed to electroly-te, a chemical reaction will begin to occur. The ! reaction of the electrolyte with -the metal creates a 20 passivation film on the surface of the metal. This passivation film is essentially nonporous, although it is ion-permeable. The film tends -to isolate the metal grains elec-trochemically. The desired electrical conductance for the film on the grains balances between increasing the rate of the passivation reac-tion by too high a conductance and decreasing the electrochemical ac-tivity of grains through too low a conductance. While a low conduc-tance reduces the rate of reac-tion of electrolyte and metal, the lo~ conduc-tance increases the stripping of metal from the 30 substrate ra-ther than from within the grains (because of -the high contac-t resis-tance between grains).
To have a high turnover number ~T) and to minimize the surface area of -the metal electrode (so that the reaction wi-th the electrolyte to form additional passivated metal is minimized), it is advantageous that stripping of electrolytically active metal preferentially occurs at -the front (outside) of the deposit ra-ther -than wi-thin -the deposi-t or a-t the surface of the underlying, nonporous substrate. If the front (outside) is not s-tripped while underlying por-tions of -the substrate are, -the front loses physical contact with the rest of the deposi-t and the substrate. As a result, the front becomes electrochemically inac-tive. Pressurizing -the electrode above the compressive strength of the deposit (i.e., to deform -the deposi-t so as to force -the grains of the deposi-t together) allows -the fron-t -to be preferentially 10 s-tripped.
Three factors may contribu-te to the resis-tance to stripping of -the different portions of the electrode during operation of the ba-ttery. These resistance factors are:
(1) the electrical resis-tance between the grain (of the deposit) in question and -the curren-t collector;
(2) the ionic resistance associated wi-th the migration of me-tal ions through the porous deposit from the grain in ques-tion; and

(3) the resistance associated with stripping a metal ion f om a grain and transporting tha-t ion through a passivating film.
Respecting factor (1), ordinarily the electrical resistance is highest for those grains which are nearest the front of the deposit. In fact, it is reasonable to assume -that the electrical resistance is essentially zero for grains which lie at the surface of the substrate.
Respecting factor (2), -the ionic resistance is highest for the substrate and reduces for grains that lie closer to 30 the front of the deposit. The ionic resistance is lowest at the front of -the deposit where the diffusion of -the ions to reach ac-tive grains is the shortest, and is highes-t at the substrate -to which the diffusion path is the longes-t. Finally, as to factor (3), -the passivating film resistance is con-trolled by -the chemical na-ture of the passivating film and cannot be substantially altered by changing the physical parameters oE the deposi-t.

By applyinc~ a compressive load to the surface of -the amalgamated deposit (preferab:ly normal -to -the deposit) that exceeds the compressive s-trength of -the deposit as explained above, a two-fold e-ffect is achieved. First, the porosi-ty of -the deposit is decreased by moving grains closer toge-ther as the deposit is compressed. Reducing the porosi-ty has the effec-t of increasing -the ionic resistance to s-tripping more for the substrate than for the front. At the same -time, the elec-trical resistance hetween grains of 10 the deposit is reduced because the surface-contact area between adjacent grains increases. The net result of the compression is, then, to increase the sum of the -three resistance factors near the substra-te and the decrease the sum of these resistances for grains near the front of the deposit and achieves the desired effect of improving the reversibili-ty of the battery. (The front is also conveniently identified as the in-terface between the electrode and the separator). Thus, -the compressive load resulting in a smooth, nonporous surface which provides 20 good electromotive activity for the electrode and allows stripping of the electrode from -the outer surface -thereof.
The presen-t inven-tion can be employed with any ba-ttery employing an elec-trode which will react with the electrolyte to form an amalgama-ted, porous deposi-t on the electrode, especially during recharging. For example, anode materials such as alkali metals, alkaline earth metals and transition metals such as zinc, will form deposits -thereon by reaction with certain electrolytes.
Thus, alkali metals, e.g., lithium, in the presence of a 30 nonaqueous elec-trolyte such as propylene carbonate including LiC104 forms a salt deposit on the alkali metal and on grains of -the alkali me-tal deposited during recharging (replating).
~ he compressive load, as explained above, is such that it will de~orm the deposi-t by compressing par-ticles or grains of the deposit closer together.
Accordingly, -the compressive load employed in the present inven-tion varie.s depencling upon -the nature of the electrode, the electroly-te and the deposit. A sof-ter rne-tal wlll require a lower compressive load. For example, the compressive load under which alkali metals de-form is typically low and all alkali metals are soft and ductile, e.g., the -tensile strength of li-thi.um is in the range of 60-80 psi. Considering that the deposi-t is a porous metal deposit in which -the void spaces are filled with liquid elec-trolyte, the compressive s-trength (i.e., force at 10 which -the material will deform under pressure) of the deposit is less -than or equal -to that for the pure metal.
The compressive load does not necessarily have to be applied continuously during charging and discharging. Appli.cation of the compressive load to compress the deposi.t may be, in fact, of short duration, for example~ by applying a compressive load for a time during the end of the recharging cycle or even applying the compressive load after recharging and pior to fur-ther use. However, the compressive load is preferably applied 20 continuously at least during recharging.
With lithium a compressive load of from about 50 to about 500 psi is preferably applied continuously during recharging. As noted above, such a compressive load on the lithium electrode (e.g., li-thium with an appropriate substrate) during recharging results in grains of material being plated thereon having columns with thei.r axes aligned substan-tially perpendicular to the substrate.
Placing a compressive load on the electrode constrains the materials from which the en-tire cell is 30 constructed. The cell components are preferably sof-t and pliable so that the load can be applied un-Lformly. Use of expanded metal grids for current coll.ectors and hard, grit-ty powders for electrode-active materials is discouraged. The separator material also should be pliable. Preferably, me-tallic foils are used as current collectors, and soft ma-terials, such as graphi-te or molybdenum sulfide (-transition metal chalcogenide cathode-active cathodes) are used ~or -the cathode. If possible, the ca-thode supplies a uni~orrn curren-t density -to assure uniform use of the substrate. Polypropylene or other suitable flexible, porous or semlpermeable separa-tors are preferred.
~ s shown in Figure 1, -the means to apply a compressive load may be a simple coil spring lO which bears upon a pressure plate 12 s-tacked atop the battery.
Of course, o-ther suitable pressure means may be used.
10 Figure 2 shows a spiral ba-t-tery wherein an elastic separator and a C--clamp lOa bear radially on the cell to supply -the desired load. In bo-th cases, the compressive load of the spring and C-clamp is sufficient to provide the desired decrease in porosi-ty of the deposit and the desired decrease in electrical resistance between grains of -the deposit.
Further explaining Figure l, an electrolytic cell (battery) has an anode 14 (with a corresponding current collector) sandwiched be-tween two cathodes 16 20 (with corresponding current collectors). Electrolyte-saturated separators 18 isolate the anode 14 from the cathodes 16 and carry the electrolyte for the cell in their pores. The anode, cathodes, and separators form a cell, which is elec-trochemically ac-tive to product current. The anode is of a composition such that a porous, amalgama-ted deposit will form thereon as discussed above.
Placed in a housing 20, the cell is compressed, as already described. The housing 20 is preferably hermetically sealed in a nonreactive atmosphere.
Directing a-ttention to Figure 3, in making a spiral cell (ba-ttery), the elasticity of two separator layers 18-18, one between the anode 14 and cathode 16, and the other on the outside, is relied upon to provide a radial compressive load on -the desired elec-trode, i.e., either the anode 14 or cathode 16, by tigh-t winding of the layers into a coil around a conductor. The tension on the separator layers is maintained by -the C-clamp lOa to provide -the desired compressive load. Polypropylene may be used for the layers 18-18.

The ~ollowing e~amples are given -to illustrate -the elec-trode appara-tus, battery and me-thods of this invention, and should not be in-terpreted to limit -the scope of -the inven-tion.
Example 1 ~ n electro]ytic cell was cons-tructed between two flat, rigid pressure pla-tes. The cathode consisted of a surface-treated molybdenite powder which was spread uniformly on an aluminum-Eoil substrate, as described in United Sta-tes Paten-t 4,251,606. The cathode provides a uniform current density for -the cell. The molybdeni-te powder was spread at 10 mg/cm2 on the aluminum foil. The area of -the ca-thode was 5.6 cm2. The anode was a similar sized shee-t of lithium foil of a thickness of abou-t 125 microns sandwiched be-tween two ca-thodes with microporous polypropylene separators (Celgard* 2500 available from the Celanese Corporation). The electrolyte was 1 M LiAsF6 in propylene carbonate. The propylene carbonate was ini-tially purified -to a -to-tal impuri-ty content of less than abou-t 100 ppm. The cathode and separators were initially saturated with electrolyte.
The cell was assembled between pressure plates, and a pressure of 27 psi was applied to the cell through the plates. The entire cell was enclosed in a hermetically sealed con-tainer filled with argon gas. A glass-to-metal seal was used for -the curren-t feed-through for the negative -terminal of -the electrolytic cell. The cell was conditioned to convert -the cathode-active material to "Phase II" LixMoS2, as described in the Uni-ted S-ta-tes Patent No. 4,22~,390. Care was -taken -to ensure -that the electrolyte did not degrade during -the conversion process. The cell was cycled (charged and discharged) at a current of 2 mA on both recharge and discharge repeatedly between a lower voltage limi-t of 1.3 vol-ts on discharge and an upper limi-t of 2.6 vol-ts on recharge. Cycling * Trade Mark ~3~

continued until -the charge capacity on discharge fell to fi~-ty percent (50%) of the charge capaci-ty measured at the end of -the -tenth cycle. The to-tal amount of charge ob-tained from cell on discharge integrated over all cycles was calculated -to be 210 mAH. CalcuLated by taking the ratio of this amount of charge as compared to the t~eoretical charge expected if the entire lithium anode was discharged in one cycle, the number of turnovers (T) for the li-thium anode was three.
Example 2 An elec-trolytic cell similar to the one eon-structed in Example 1 in all respec-ts, excep-t -that the electrodes were subjected to a pressure of 50 psi, was cycled under identical conditions to those deseribed in Exampie l. The number of -turnovers (T) for -the lithium anode in this second cell equaled eigh-t.
Example 3 An electrolytic cell similar -to the one cons-tructed in Example 1 in all respects, excep-t that the 20 electrodes were subjected to a pressure of lO0 psi, was cycled under iden-tical eonditions to those deseribed in Example l. The number of turnovers (T) fGr -the lithium anode in this third eell equaled nine.
Example 4 An electrolytic eell similar in all details to the eell of Example 1, exeept that the eleetrodes were subjeeted to a pressure of 170 psi, was eyeled under identieal eonditions -to those deseribed in Example 1. ~`he number of -turnovers (T) of the lithium anode in -this 30 fourth eell equaled eleven.
Example 5 An eleetro~Ly-tic cell similar in all respects to the cell cons-trueted in Exarnple ~" except that the supporting electrolyte used was 0.5 M LiCl04 ins-tead of 1 M LiAsF6, was constructed and -tested under the same conditions as those of Example 3. The number of turnovers (T) equaled seven.

Example 5 shows -tha-t the appli.cation of pressure played a-t least as importan-t a role in determining -the number of turno~ers as -the choice of -the electro].yte in -the cell. Although -the nurnber of turnovers varies with the choice of the elec-trolyte, -the number of turnovers achie~able by applying pressure to the cell is always greater -than the number of -turnovers possible when running -the cell freestanding.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows.

1. An electrode apparatus comprising an electrode comprising an alkali metal which forms a porous, exterior, amalgamated deposit thereon; and means for applying a compressive load to the electrode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of said amalgamated deposit.

2. An electrode apparatus according to claim 1, wherein said electrode comprises lithium.

3. An electrode apparatus according to claim 1, wherein said amalgamated deposit comprises electrolytic, metal grains having individual passivation films.

4. An electrode apparatus according to claim 1 or 2, wherein said means for applying a compressive load applies said load continuously.

5. An electrode apparatus according to claim 2, wherein said electrode further comprises a substrate for said lithium and wherein said means for applying a compressive load applies to said load continuously during recharge such that the material plated onto the electrode during recharge comprises close packed grains having columns with their axes aligned substantially perpendicular to said substrate.

6. A battery cell comprising a cathode, an anode comprising an alkali metal, and an electrolyte, wherein said anode forms a porous, exterior, amalgamated deposit thereon; and further comprising means for applying a compressive load to said anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of said amalgamated deposit.

7. A battery cell comprising a cathode, a non-aqueous electrolyte; an alkali metal anode which forms a porous, exterior, amalgamated deposit thereon; and means for applying a compressive load to the anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of the amalgamated deposit.

8. A battery according to claim 6 or 7, further comprising a separator disposed between the anode and cathode

9. A battery cell according to claim 6 or 7, wherein said means for applying a compressive load applies said load continuously.

10. A battery cell according to claim 6 or 7, wherein said anode comprises lithium on a substrate and wherein said means for applying a compressive load applies said load continuously during recharge such that the material plated onto the electrode during such recharge comprises close packed grains having columns with their axes aligned substantially perpendicular to said substrate.

11. A battery comprising:
(a) a cathode;
(b) an alkali metal anode having an alkali metal substrate interior and an amalgamated deposit exterior comprising electrolytic, alkali metal grains having individual passivation films;
(c) a separator for the anode and cathode;
(d) a nonaqueous electrolyte; and (e) means for applying continuously a compressive load to the electrode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of said amalgamated deposit.

12. The battery according to claim 6 or 7, wherein the cathode provides a uniform current density for the battery.

13. The battery according to claim 11, wherein the cathode is a transition metal chalcogenide cathode.

14. The battery according to claim 13, wherein the transition metal chalcogenide is selected from the group consisting of molybdenum dioxide and molybdenum disulphide.

15. The battery according to claim 11, wherein the cathode is a metallic foil coated with a coating selected from the group consisting of graphite and molybdenum sulfide.

16. The battery according to claim 15, wherein the metallic foil is aluminum.

17. The battery according to claim 11, wherein the separator is a flexible, polymer-based, porous plastic.

18. The battery according to claim 17, wherein the separator is microporous polypropylene.

19. The battery according to claim 11, wherein the alkali metal is lithium.

20. The battery according to claim 19, wherein the electrolyte solvent is propylene carbonate.

21. The battery according to claim 19, wherein the electrolyte is selected from the group consisting of LiAsF6 and LiClO4 in propylene carbonate.

22. The battery according to claim 19, wherein the load is between about 50 and 500 psi.

23. A battery comprising:
(a) a cathode which provides a uniform current density for the battery;
(b) an alkali metal anode having an alkali metal substrate interior and an amalgamated deposit exterior comprising electrolytic, alkali metal grains having individual passivation films and being formed by replating alkali metal onto the anode;
(c) a separator for the anode and cathode;
(d) a nonaqueous electrolyte; and (e) means for applying continuously a compressive load to the anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of the amalgamated deposit.

24. The battery according to claim 23, wherein the cathode is a transition metal chalcogenide cathode containing LixMoS2 and the anode is lithium, where 0 < X ? 3.

25. A method of making a battery, which has at least one electrolytic cell, to increase the reversibility of the battery by increasing the number of turnovers available within an electrode of the cell, comprising the steps of: constructing an electrolytic cell having a cathode, an anode, and an electrolyte, wherein said anode comprising an alkali metal forms a porous exterior amalgamated deposit thereon; and applying a compressive load to said anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of said amalgamated deposit.

26. A method of making a battery, which has at least one nonaqueous electrolytic cell, to increase the reversibility of the battery by increasing the number of turnovers available within an alkali metal electrode, comprising the steps of: constructing an electrolytic cell having a cathode, a non-aqueous electrolyte, a separator, and an alkali metal anode which forms during recharging a porous, exterior, amalgamated deposit thereon comprising electrolytic, alkali metal grains; applying a compressive load to the anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of the amalgamated deposit.

27. The method according to claim 26, wherein the cathode and separator are substantially planar and wherein the load is applied by sandwiching the cell between flat pressure plates.

28. The method according to claim 26, further comprising the step of winding the anode, cathode, and separator to form a spiral cell.

29. The method according to claim 25 or 26, wherein the load applied is between about 50 and 500 psi.

30. A method of making a battery, which has at least one electrolytic cell containing an alkali metal anode, to increase the reversibility of the battery by increasing the number of turnovers available with the alkali metal electrode, comprising the steps of:
(a) constructing an electrolytic cell having a cathode containing LiXMoS2, an electrolyte, a separator, and a lithium anode, where 0 < X ? 3;
(b) applying continuously a compressive load to the anode so that an amalgamated deposit thereon, when formed comprising electrolytic, lithium metal grains having individual passivation films is compressed so as to enhance stripping from the outer surface of the amalgamated deposit; and (c) converting the cathode-active material to "Phase II" LixMoS2.

31. The method according to claim 30, further comprising the step of cycling the battery to charge and to discharge the cell while maintaining the compressive load.

32. A method according to claim 31, wherein said anode further comprises a substrate for said lithium and wherein said compressive load is such that the material plated onto the electrode during recharge comprises close packed grains having columns with their axes aligned substantially perpendicular to said substrate.

33. The method according to claim 30, further comprising the step of containing the cell in a nonreactive environment.

34. A method for increasing the reversibility of a cell including a cathode, an anode comprising an alkali metal and an electrolyte, wherein said anode forms a porous exterior amalgamated deposit thereon, said method comprising applying a compressive load to said anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of said amalgamated deposit.

35. A method for increasing the reversibility of a cell including a cathode, an alkali metal anode which forms during recharging a porous exterior, amalgamated deposit comprising electrolytic, alkali metal grains, and a non-aqueous electrolyte, said method comprising applying a compressive load to the anode such that the deposit, when formed, is compressed so as to enhance stripping from the outer surface of the amalgamated deposit.

36. A method according to claim 34 or 35, wherein said cell includes a separator disposed between said anode and cathode.

37. A method according to claim 34 or 35, wherein said application of a compressive load is performed continuously during discharging and recharging.

38. A method according to claim 34 or 35, wherein said deposit is formed during recharging of the battery.

39. A method according to claim 35, wherein said deposit comprises electrolytic, alkali metal grains having individual passivation films, said grains being formed upon recharging of the cell.

40. A method according to claim 39, wherein said electrode comprises lithium on a substrate and wherein the compressive load is applied continuously during recharge such that the material plated onto the electrode during such recharge comprises close packed grains having columns with their axes aligned substantially perpendicular to the substrate.

41. An electrode apparatus according to claim 1, wherein the compressive load of said means is at least as great as the compressive strength of the amalgamated deposit.

42. The battery according to claim 11, wherein the cathode provides a uniform current density for the battery.

43. A battery according to claim 24 or 42, wherein the compressive load of said means is at least as great as the compressive strength of the amalgamated de-posit.

44. A method according to claim 26, 27 or 31, wherein the compressive load applied is at least as great as the compressive strength of the amalgamated deposit.

45. A method according to claim 34 or 35 wherein the compressive load applied is at least as great as the compressive strength of the amalgamated deposit.

46. The battery according to claim 24 wherein said transition metal chalcogenide cathode containing LixMoS2 is in "Phase II".

47. The battery according to claim 46 wherein the compressive load applied is between about 50 and 500 psi.