CA1105035A

CA1105035A - Alkali metal salts of complex anions containing heteroatom substituents and electrolyte compositions containing these

Info

Publication number: CA1105035A
Application number: CA307,920A
Authority: CA
Inventors: Thomas A. Whitney; Lawrence P. Klemann
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1977-08-24
Filing date: 1978-07-21
Publication date: 1981-07-14
Also published as: NL189200C; IT7826966A0; IT1098255B; DE2833943A1; CH646150A5; DE2833943C2; GB2003136A; NL7808677A; FR2401168B1; FR2401168A1; NL189200B; GB2003136B; JPS5448757A

Abstract

ABSTRACT OF THE DISCLOSURE
Alkali metal salts of complex anions having heteroatom substituents are described. The compounds are those having the formula:
ZMRxQy wherein Z is an alkali metal selected from the group consisting of lithium and sodium, M is a metal selected from the group consisting of Zn, Cd, B, Al, Ga, Sn (stannous), P and As, the Rs are certain aralkyl and alkyl radicals, the Qs are certain heteroatom containing groups; x is zero or a positive interger, and y is a positive integer, subject to the provisos that the sum of is equal to one plus the valance of the metal M and that, when M is boron, y comprise: (a) organic solvents selected from the group consisting of inertly substituted and unsubstituted ethers, esters, sulfones, organic sulfites, organic sulfates, organic nitrites and organic nitro compounds; and (b) electrolytically active alkali metal salts including alkali metal complex anion salts described above.

Description

BACKGRO~ND OF THE INVENTION
1. Field of the Invention The present invention relates to novel compounds and more particularly to novel alkali metal salts of complex anions havin~ heteroatom substituents.
The present invention is also directed to electrolyte compositions conta~ning certain organic solvents and the mentloned compounds.

2. Prior Art Statement It is believed that the compounds of the present invention have not been heretofore made or discovered and that no compounds existed heretofore which would render the compounds of the present invention obvlous. A prior art statement in support of this position will be submitted within three months from the filing date hereof.
DESCRIPTION OF THE PRESENT I~VE~TION
-The present invention is directed to compounds of the following formula ZMRxQy Sl) wherein Z is an alkali metal selected from the group consistlng of lithiuM
and sodium, M is a metal selected from the group consisting of Zn, Cd, B, Al, Ga, Sn (stannous), P and As, the Rs are inertly substituted and unsubstituted organic radicals, the Qs are heteroatom containing groups more specifically described below, x i.s zero or a positive integer, and y is a positive integer, subject to the provisos tbat the sum of x plus y is equal to one plus the valence of the metal M and that, when M ls boron, x is one, two or three. Preferably, y i9 one, two or three.
The alkali metal represented by Z in formula (1) above is selected from the group consisting of lithium and sodium, with lithium being the pre-ferred embodlment.
The metal M in Formula ~1) is any of zinc, cadmium, boron, aluminum, , , ~5~` 3~i gallium, tin (stannous), phosphorus and arsenic. Desirably, M is selected from the group consisting of boron, aluminum, phosphorus and arsenic. Most preferred is boron.
~ le variable R in Formula (1) above occurs x number of times and each R may be the same or different from the o~her Rs in a given formula. As mentioned, the Rs in general represent inertly substituted and unsubstituted organic radicals. Of these, the unsubstituted radicals are preferred. By "inertly substituted" is meant radicals containing substituents which have no detrimental effect on the formation or stability of the compounds and do not otherwise negate the utillty of the compounds. These organic radicals R may be inertly substituted and unsubsti~uted alkyl radicals and aralkyl radicals.
By "aralkyl" is meant an alkyl radical con-taining a pendant aryl group. It is intended that these alkyl radicals and aralkyl radicals include linear and branched radicals, as well as those in which at least a part of the alkyl moiety may be carbocyclic. The organic radicals R may be selected from the group consist-lng of alkyl radicals having 1 to 25 carbon atoms, and aralkyl radicals having 7 to ~5 carbon atoms. Desirable organic radicals are the alkyl radicals having 1 to 10 carbon atoms and the aralkyl radicals having 7 to 10 carbon atoms. Preferred are ~he alkyl radicals having 1 to 4 carbon atoms.
Particularly useful are the compounds wherein R represents methyl andtor ethyl radicals.
The variable Q represents heteroatom containing groups and occurs a suEElcient number o tlmes ln ~he compound`of the present lnvention to render a total valence of y. In general, Q may represent one or more heteroatom containing groups selected from the group consisting of:

- 3 -:
~ ~ , : . , ,: , . . ~ - . . .:
.
. ~

5¢~3~i ~ -N 3 1~

and any dimeric or trimeric composite of the foregoing radicals, and any group composed of two or three o the above structural units linked directly or throu~h additional carbon (as methylene or methine carbon)~ wherein each R' may be the same or differen~ and is selected from the group consisting of hydrogen and any R as defined above. Preferably, R' is hydrogen.
As mentioned, the variable x in Formula (1) above ls zero or a posit-lve integer, y is a positive integer and the sum of x plus y is equal to one plus the valence of the metal M, except that when M is boron, y is one, two or ~hree. Also, as mentioned, x represents the number of organic radicals R which occur in the compound of the present invention9 whereas y represents the total valence of the heteroatom containing groups Q which are prese~t in the compound. When all of the Qs in the formula are the preferred monoanoin substituents, the total valence y also equàls the total number of such heteroatom substituents present. However, when polyanion substituents are lncluded, e.g., dianion, trianion, etc., substituents, the total number of such sùbstituents ln the compound will be less than y.
~ ~Nonlimiting~examples of the present invention alkali metal salts o~ comple~ anions containing heteroatom substituents include:

` ~: ::

.

:
:

-~55~

~ Li ( ~(~3)2 3 r CH31 s l, J~

- N~ ¦
7 ~iB(C2Hs)~

. . ......

Li:e (C 21I5 ) 2 [~;~3J 2 1~ Li~CH3[~3, . LiB (C3H 7) 2 ~ 1 2 156 LiBC2H~33 ~7 Li~(C2H5)3 19 I.iA].[~

22 NaB(c~l5 j3[~
23 N~Al [~ and : - :

Z6 l~ q2~s~2 :

The compounds of the present invention may be prepared by one of a number of techniques. Those compounds containing at least one monovalent heteroatom substituent may be prepared by reacting an alkali metal monovalent heteroa-tom substituent compound with the metallic or metalloid compound which corresponds to the ultimate present invention compound desired. This reaction may be represented by the ~ollowing equation.
Q ~ MRxQy~ ZMRxQy (A) wherein ZQ is an alkali metal monovalent heteroatom substituent compound and all other variables as described above.
Those compounds of the present invention which contaill at least one organic radical substituent R may be prepared by re~cting an alkali metal organo compound with the metallic or metalloid compound which corres-ponds to the ultimate present invention compound which is desired. This particul.ar reaction may be represented by the ~ollowing equation:
~RX~lQy ~ZMRxQy (B) wherein all oi the variables are as deiined abo~e.
Compounds of the present lnvention which may be prepared by the technique such as that illustrated in Equation (A) above may alternatively be prepared by using an alkali metal hydride or al`kali metal amide in place of the alkali metal salt ZQ according to the following equations:

~Qy l ~ IQ _ zQ ~ ~RxQy~ 2 ~

ZM~xQy (C) .
~..
~ 6 ~

.
,: , . , : ~
. . , , :, . . ' : :

, . -. .. . ~ : . : .

P`3~
~ --~

and zN112 ~ HQ P
zQ -~ NM3 t ~ Y 1 xQy ~D) wherein the variables are as defined above. In fact, for the sodium compounds, the method represented by the reactions set forth in Equation (C) is preferred.
Compounds of the present invention containing both organic radical substituents and monovalent (mono-anionic~ heteroato~ substitutents may be prepared by any of the above techniques.
Compounds of the present invention containing neither organic substitutent R nor monovalent heteroatom containing groups Q, i.e. compounds of the present inventlon containing only polyanion heteroatom substltuents, may be prepared by nucleophilic substitution on the metal or metalloid M.
For example, the following reaction is typical:

l,i ~ ~ ',.

> ~ ~lC13 Ll-N ~
_ _ ..
.

N ~ 1 +31iC1 (E) l ~ i ` .

' , . ,, ., ,., , , : ~, . . ' ' ' . ~ , .. . .. . . .. . . . . .

The above reactions may be car~ied out at any operable pressure and temperature, and room temperature and pressure conditions will allow the reaction to readily occur in most instances. Desirably, the reactions are carried out at about -100 to about 150C7 and preferably at about -20 to about 80C, e.g. room te~perature. In general, any compatlble organic solvent may be used as a vehicle for the abo~e reactions. Typical among these are hydrocarbons such as pentane, heptane, benzene~ toluene, etc., and ethers such as diethyl ether, tetrahydrofuran and dimethoxyethane and the like.
Other compatible solvents may be within the pur~iew of the artisan.

The present in~ention is also directed to electrolyte composi-tions containing the above compounds as represented by ~ormula (l)o More speciflcally, the electrolyte compositions of the present invention co~prise organic solvent and electrolytically active alkali metal salts including an alkali metal heteroatom substituted complex anion salt o~ ~o~nwla ~1) above.
Thus, a mixture o~ salts is contemplated, at least one o which is a ~ormllla (1) type. The other salt or salts in the mixture may be any electrolytically active alkali metal salt which i.s compatlble with the Formula (1) type compound, e.g. LiBr, LlI and the like. Also contemplated is the electrolyte which contains only one or more salts of ~ormula (1). Thus, the e~pression "electrolytically acti~e alkali metal. salts :Lncluding an alkall metal hetero-catom substituted complex anion salt" should be. construed to include~
mi~tures of alkali metal heteroatom substit~l~ed complex an:lon salt(s) and other compatible alkall matal salt(s), and (2) one or more alkali metal heteroatom substituted complex anion salts without other salts. Preferred is the electrolyte containing the heteroatom substi~uted complex an~on salt(s) wlthout other salts.

" :
:
r ~

. . ~ : . . . ~ :: :

The organic sol~ent employed ~n the electrolyte composition of the present inrentlon is generally one selected from the group consisting of inertly substituted and unsubstituted ethers, esters, sulones, organic sulfites, organic sulfates, organic nitrites and organic nitro compounds.
By "inertly substituted" solvent is meant one which contains substituents which have no detrimental effect on the electrolytic properties of the elec~
trolyte composition in the context of its ef~ectiveness in electrochemical cells. These solvents may be any of thc foregoing which will functlon as either a diluent or as a complexing solvent with the organometallic alkali metal salt and which will, with the salt, produce an effective electrolyte.
Thus, the sol~ents which are included are those composed of one or more compounds selected ~rom straight chain ethers, polyethers, and cyclical ethers; including such ethers as the acetals, ketals, and ortho-esters; and organic esters, sul~ones, organic nitro compounds and nitrites and organic sulfates and sulfites. Examples include propylene carbonate, tetrahydrofuran, dioxolane, furan~ sulfolane, dimethyl sul~ite, nitrobenzene, nitromethane and the like. The preerred solvents are the ethers, For example, dioxolane, dimethoxyethane, and mixtures of these are useul. Preferred is a solvent containing dioxolane.
In general, sufficient organic solvent must be utiliæed to ef~ectively render the organometallic alkali metal salt electrolytically active (i.e., adequately conductive) when employect in an electrolytic cell.
The solvent may be a mixture of compounds as suggested above, and may con~ain known electrolyte additives which are compatible with the solvent and the partlcular salt employed. ~s to the amount o~ salt to be employed in the oxganic solvent, this will vary tremendously with the specific solvent used~
the salt chosen and the type o elec~rochemical cell per~ormance which is desiredi In any even~, an electrolytically active amount of salt must be .~ . ., ' : , ., -. ' :.:: ' ' - , ' ~ : ' ~-, '' ,, , ; ' S

added to the solvent. Typically~ at least ~bout 0.01 molal of salt up to saturation may be used, e,~,, a~out 0,01 to about 10 molal may be used and preerably about 0.5 to about 3 molal may be used.
The ~ollowing examples are presented as merely illustrative of the present invention; and the invention should not be construed to be limited thereto:

-N-lithiopyrrole is prepared by the addition of n-butyl lithium to a solution o~ pyrrole in pentane at room temperature, The suspension is then filtered and the solld is washed with pentane and dried under a ~itrogen flow to constant weight. Solutions of LiB(C2H5)3 l ~ ~ are prepared in pure dioxolane and 70l30 dioxolane-d~imethoxyethane by adding solid ~-lithiopyrrole to solutions o~ B(C2H5)3 to make the 1:1 salt. H ~MR analysis con~irms the ~ormation o~ the compound: C2H5 resonances: complex multiplet from 50.6 to 1,5 centered a~ ~1.1; pyrrole resonances: triplet at ~6.4 3-1,8 and tri~let at ~7,35 J=1,8, The trlethyl~b:oron resonances of the product salt are completely consistant ~ith comple~ anlon ~ormat~on based on the NMR spectrum of a triethyl boron re~erence, In order to test the electrolytic capability o~ the compound obtained in Example l, the compound is dlssol~ed ln pure dioxolane at varlous concentrations and the reslstivJties o~ the solutions are measured using a Barnstead Model Y~-700B Conduc~i~lty Brldge and a Yellow 5prings Instrument Co, Model~YSI 3403 Cell having plat~num electrodes and ha~ing a cell constant o - l,O, The results~presented in~Table I establish very low resistivity at the various concentrations tested~

~ . ... ~ . . . ..................................... . .

::: - . ~ : : , , .. . . . .

;~ ~

TABL~ I
_ ~esistivity o~ LiB~C2H5)3 L~
in Dioxolane , Concentration~esistivity (molal) _ (ohm-cm) 1.0 140 1.5 134 2~0 156 2.5 204 3.0 296 The compound o~ Example l is again tested in accordance with the procedure of Example 2, except that a dioxolane-dlmethoxyethane solvent is used. The resistivity is found to be very low as shown in Table II:
TABLE 'LI r Resistl~ity oE LiB~C2H5) In Dioxolane-Dimethoxyethane (70/ ~ V~V) ConcentrationResistivlty (molal) (ohm-cm) 1.0 92 ~: ]':5 95 :
2.0 116 2.5 : 1.53 ..
, E~AMP~E 4 N-lithioindole is p~epared in accordance with the procedure o~

Example 1. Solutlons o~ LiB(C2H5)3 [ ~ ~ are prepared in pure dioxolalle and 70/30 dioxolane-dimethoxyethane by adding golid N-lithioindole to solutions .

-: -of B(C2H5)3 to make the 1:1 salt. lH N~R analysis confirms the formation o~
the compound based on re~erence spectra of the components.
EX~MPLE 5 The compound o~ Example 4 is tested in accordance ~i~h Example 2. Table III, below, shows the data obtained.
T~BLE III r~,l Conducti~itY of LiB(C2H5)3 LW~
in D _xolane _ - ' Concentration Resistivl~y (~olal) (ohm-cm 0.5 22 1.0 155 1.5 168 2.0 216 2.5 ~03 The compound o~ ~xample 4 i~ tested in accordance with Example 3. The data are sho~n in Table IV.
T~BLE IV r~l Conductivity o~ LiB(C2H5) in Dioxolane-Dimethoxye~hane ~ (70t30, V/V) Concentration Resisti~ity (molal~ ~ohm-cm) 0.24 255 0'5 166 l.0 124 1.5 134 2.0 177 2.5 286 ~ 12 -.
. . :-: .

EXA~CPLE 7 _ A 1.56 g (22.9 mmoles) portion of imidazole is dissolved in lO0 ml of tetrahydrofuran and the solution is cooled to ~60 C and 10 ml -(22.9 m~oles) of n-C4H9Li solution in hexane is added dropwise with stirring.
The reaction mixture ls then allowed to warm to room temperature over 75 minutes. The reaction mixture is then filtered through a fritted disk (~STM 10-15) and a white solid lithium salt of imidazole ~lithioimidazole-A) is isolated, dried weight l.lg.
The ~iltrate is evaporated to dryness under high ~acuum and lithioimidazole-B is recovered, wt. 1.04g.
That both produc~s are lithium salts of imidazole is confirmed by lH and 13C NM~ analysis based on reference spectra as well as by hydrolysis of both products in D20 with the regeneration of imidazole as determined by N2~ .
Solutions of LiB(C2H5)3 [lithioimida~ole-A~and LiB(C2H5)3 - ;
~ithioimidaæole-B~ are prepared in dioxolane uslng 1:1 mole ratios of B(C2H5)3 and lithioimidazole-~ and lithioimidazole-B respecti~ely. NMR
analysis conflrms the Eormation of the compounds based on reference spectra of the components.

LiB(C2H5)3 ~lithioimidazole-~ in dioxolane is tested in accordance with Example 2. Table V illustrates the data obtained.

. .

.~ 13 -' ' ' ' - ' ~ , . , ' ' . . . .
.
,: : , T~BLE V
. .. ~
Conductlvity o~ l.iB(C H5)3[1ithioimidazole~]
ln Dloxo~ane ConcentrationResistivity (molal) _ (ohm-cm) 0.5 ~0 1.0 557 l.S 560 ~iB(C2H5)3 [lithioimidazole-B] i~ dloxolane ls tested in accordance with Example 2. Table ~I sets forth the results obtained.

_ABLE VI

Conductivity of LiB(C2~1 )3 Clithioimidazole-B¦
in Dioxo~ane Concentration Resis~lvity (molal) (obm-cm) O.S4 262 1.17 225 1.23 230 ~X~MPLE iO

In an ~2 dry box, an excess of NaH ln oll (6g) is washed on a s~nte~ed glass funnel with 400 ml o~ pentane. The solid NaH is then trans-~erred to an Erlen~e.yer flas~ with 40 ml of dloxolane. A solution o~ tri-ethylboron (19.6 g9 0~.2 le)~in 30 ml of dioxolane is then added slowly :
with~stirring. ~n e~othermic reactlon ls obser~ed. ~ter this addition is complete, stirrlng is contlnued ~or 30 minutes at room temperature and the mixtu~e is ~iltered. The residual NaH is washed with 15 ml of dioxolane and the washings are added to~the flltrate. To the flltrate ls then added, drop~
wise o~er 45 mlnutes, a~sol~tion of~pyrrole (13.4 g 0.2 mole) in 30 ml of - ~

3~i dioxolane. Vigorous gas evolution is o'bserved during the addltion. ~fter this addition is complete, stlrring is continued ~or 1,5 hours. ~ sample of this solution is then analyzed by NMR, Comparison of the chemical shifts for the ethyl protons with a B(C2H5)3 standard in dioxolane support ormation of NaB(C2H5)3(C4H4N). Integration shows the solute concentration to be 2.0 moles per liter of dioxolane. This solutlon and subsequent dilutions deri~ed from it~ are measured for their specific resisti~ities: molal (ohm cm~: 2.0 (210), l,S (204), 1,0 (230), and 0.75 (267), EX~MP~E 11 The following general method of construction is used to prepare cells for use in testing of electrolytes containing the novel compositions set forth above.
The test cells contain a lithium or sodium anode prepared by pressing alkali me~al ribbon onto expanded tantalum screen, The cathode iæ '' a porous cake of a mixture of T~.S2 and Teflon (90-95% TiS2 and 5-10% Teflon) pressed onto an expanded tantalum screen. The anode and cathode are ~itted lnto microporous polypropylene bags sold under the name Celgard by Celanese Corpora~ion of America, New York, A glass mat is placed between the anode and cathode. Each cell also contaLns a re~erence al'kali metal electrode con-structed by pressing the appropriate alkali metal onto expanded tantalum screen, The re~erence elec~rode is fitted into a m:Lcroporous polypropylene bag and ,separated ~rom the ad~acent cathode by means of a glass mat. In t'he completed cell the reference electrode is located on one side of the cathode while the anode i9 located on the opposite slde, Into one such cell containing a lithium anode and a TiS2 cathode containing a weight o~ active material so as to provide 96.7 mA Hr. of theo~
retical capacityp is placed the electrolyte o~ Example 4 containing 2.0 moles of LiB(C2H5)3 [I ~ ] per lieer of d.Loxolane. This cell is discharged at a cusrent .
.
.
.,' : . ~ . , . .: :
-. . : . . : ~
.

~ii¢~3~

of 64 n~ to afford utilizatlon oE 87 mAHr capaclty at the end o~ the first discharge. The cell is then recharged at 16 mA.
The discharge cycle is then repeated. A~ter 10 discharge/charge cycles the accurnulated capacity drawn from the cell ls 822 n~ Hr. This demonstrates the rechargeable character of the battery, and the ability of the novel solute composition to function as a non-aqueous electrolyte in dioxolane.

Lithium aluminum hydride (1.14 g, 30 mmole~ is suspended in 30 ml o~ dioxolane under a dry ~2 atmosphere. Pyrrole ~9g, 134 mmole~ is added dropwise and ~igorous gas eyolution is observed. After stirring one houxg the mixture is filtered. The specific resistivity o~ the filtrate i9 178 ohm cm. The 1~l ~MR spectrum o~ this solutlon is consistant wlth a 0.95 ~olal concentration o L~ 4 in dioxolane. The filtrate i9 stripped to give 19.9g of crude crystalline product containing dio~olane. The product ls washed with n-heptane and dried under high vacuum with heating af~ording a product weighing 12.5 g.

i 20 ~ 16

Claims

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

1. A compound having the formula:

ZMRxQy wherein Z is an alkali metal selected from the group consisting of lithium and sodium;
wherein M is a metal selected from the group consisting of Zn, Cd, B, Al, Ga, Sn (stannous), P, and As;
wherein R represents radicals which may be the same or different and are selected from the group consisting of alkyl radicals having 1 to 25 carbon atoms, and aralkyl radicals having 7 to 25 carbon atoms;
wherein Q represents heteroatom containing groups selected from the group consisting of:

, , and and any dimeric or trimeric composite of the foregoing radicals, and any group composed of two or three of the above structural units linked directly or through an additional carbon, wherein each R' may he the same or different and is selected from the group consisting of hydrogen and any R as defined above;
wherein y is zero or a positive integer and equals the total number of R radicals present; and wherein y is a positive integer and equals the total valence of all Q radicals present, subject to the provisos that the sum of x plus y is equal to one plus the valence of the metal M, and that when M is boron, y is equal to one, two or three.

2. The compound of claim 1 wherein said metal M is selected from the group consisting of B, Al, P and As.

3, The compound of claim 2 wherein the radicals R are selected from the group consisting of alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

4. The compound of claim 3 wherein the R' radicals are selected from the group consisting of hydrogen, alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

5. The compound of claim 4 wherein y is equal to one, two or three.

6. The compound of claim 5 wherein said metal is boron.

7. The compound of claim 6 wherein the radicals R are selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms.

8. The compound of claim 7 wherein the radicals R are selected from the group consisting of methyl and ethyl.

9. The compound of claim 8 wherein the R' radicals are selected from the group consisting of hydrogen, methyl and ethyl.

10. The compound of claim 9 wherein the R' radicals are hydrogen.

11. The compound of claim 1 wherein said alkali metal is lithium.

12. The compound of claim 11 wherein said metal M is selected from the group consisting of B, Al, P and As.

13. The compound of claim 12 wherein the radicals R are selected from the group consisting of alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

14. The compound of claim 13 wherein the R' radicals are selected from the group consisting of hydrogen, alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

15. The compound of claim 14 wherein y is equal to one, two or three,

16. The compound of claim 15 wherein said metal is boron.

17. The compound of claim 16 wherein the radicals R are selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms.

18. The compound of claim 17 wherein the radicals R are selected from the group consisting of methyl and ethyl.

19. The compound of claim 18 wherein the R' radicals are selected from the group consisting of hydrogen methyl and ethyl.

20. The compound of claim 19 wherein the R' radicals are hydrogen.

21. An electrolyte composition comprising:
(a) an organic solvent selected from the group consisting of inertly substituted and unsubstituted ethers, sulfones, organic sulfates, organic sulfites, organic nitrites and organic nitro compounds; and (b) electrolytically active alkali metal salts including an electrolytically active amount of an alkali metal salt having the formula:
ZMRxQy wherein Z is an alkali metal selected from the group consisting of lithium and sodium;
wherein M is a metal selected from the group consisting of Zn, Cd, B, Al, Ga, Sn (stannous), P and As;
wherein R represents radicals which may be the same or different and are selected from the group consisting of alkyl radicals having 1 to 25 carbon atoms, and aralkyl radicals having 7 to 25 carbon atoms;
wherein Q represents heteroatom containing groups selected from the group consisting of:

, , and and any dimeric or trimeric composite of the foregoing radicals, and any group composed of two or three of the above structural units linked directly or through an additional carbon, wherein each R' may be the same or different and is selected from the group consisting of hydrogen and any R as defined above wherein x is zero or a positive integer and equals the total number of R radicals present; and wherein y is a positive integer and equals the total valence of all Q radicals present, subject to the provisos that the sum of x plus y is equal to one plus the valence of the metal M, and that when M is boron, y is equal to one, two or three.

22. The electrolyte composition of claim 21 wherein said organic solvent is one or more ethers.

23. The electrolyte composition of claim 22 wherein said metal M
is selected from the group consisting of B, Al, P and As.

24. The electrolyte composition of claim 23 wherein the radicals R
are selected from the group consisting of alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

25. The electrolyte composition of claim 24 wherein the R' radicals are selected from the group consisting of hydrogen, alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

26. The electrolyte composition of claim 25 wherein y is equal to one, two or three.

27. The electrolyte composition of claim 26 wherein said metal M is boron.

28. The electrolyte composition of claim 26 wherein the radicals R are selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms.

29. The electrolyte composition of claim 28 wherein the radicals R are selected from the group consisting of methyl and ethyl.

30. The electrolyte composition of claim 29 wherein the R' radicals are selected from the group consisting of methyl and ethyl.

31. The electrolyte composition of claim 30 wherein the R' radicals are hydrogen.

32. The electrolyte composition of claim 31 wherein the solvent contains dioxolane.

33. The electrolyte composition of claim 32 wherein the concentration of the alkali metal salt in said solvent is about 0.01 to about 10 molal.

34. The electrolyte composition of claim 33 wherein the concentration of the alkali metal salt in said solvent is about 0.5 to about 3 molal.

35. The electrolyte composition of claim 21 wherein said alkali metal is lithium.

36. The electrolyte composition of claim 35 wherein said organic solvent is one or more ethers.

37. The electrolyte composition of claim 36 wherein said metal M
is selected from the group consisting of B, Al, P and As.

38. The electrolyte composition of claim 37 wherein the radicals R
are selected from the group consisting of alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

39. The electrolyte composition of claim 38 wherein the R1 radicals are selected from the group consisting of hydrogen, alkyl radicals having 1 to 10 carbon atoms and aralkyl radicals having 7 to 10 carbon atoms.

40. The electrolyte composition of claim 39 wherein y is equal to one, two or three.

41. The electrolyte composition of claim 40 wherein said metal M
is boron.

42. The electrolyte composition of claim 41 wherein the radicals R
are selected from the group consisting of alkyl radicals having 1 to 4 carbon atoms.

43. The electrolyte composition of claim 42 wherein the radicals R
are selected from the group consisting of methyl and ethyl.

44. The electrolyte composition of claim 43 wherein the R' radicals are selected from the group consisting of methyl and ethyl.

45. The electrolyte composition of claim 44 wherein the R' radicals are hydrogen.

46. The electrolyte composition of claim 45 wherein the solvent contains dioxolane.

47. The electrolyte composition of claim 46 wherein the concentration of the alkali metal salt in said solvent is about 0.01 to about 10 molal.