TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation: No general preparation is given.Preferred Components: The concentration of (I) in the solvent is 0.01 - 1 molar. The solvent is ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl trifluoroethyl carbonate, dimethoxyethane, diglyme, triglyme, propylene carbonate, trifluoropropylene carbonate, chloroethylene carbonate, vinylene carbonate, butylene carbonate or dimethylvinylene carbonate (preferably ethylene carbonate, propylene carbonate, dimethyl carbonate or diethylene carbonate).    TECHNOLOGY FOCUS - POLYMERS - The solvent is aprotic gel polymer or polymer matrix. Preferred Definitions:    x = 5, 8, 10 or 11.    Provided that when x is 10 then Z is Cl and when x is 10 or 11, then Z is Cl or Br.    SPECIFIC COMPOUNDS - Li2B12F5H7, Li2B12F6H6, Li2B12F7H5, Li2B12F8H4, Li2B12F9H3, Li2B12F10H2 and Li2B12F11H are specifically claimed as (I).    EXAMPLE - Li2B12F11H (3 g) was dissolved in 1M HCL (110 ml) and bromine (1.4 ml) was added. The mixture was heated to 100 degrees Celsius for four hours. The mixture was again heated to 100 degrees Celsius and chlorine gas was bubbled through it. After six hours of bubbling chlorine the solution was purged with air to give Li2B12F11Cl (test) (2.55 g) solution. Another lithium electrolyte solution Li2B12Cl12 (control) was prepared. The oxidative stability of both the solutions was assessed using CH instrument potentiostat under laboratory condition. The electrode was a platinum disc (2 mm) and potentials were referenced to a Ag/Ag+ (silver wire immersed into 0.01 M silver nitrate in 0.1M acetonitrile tetra n-butyl amine tetrafluoroborate in a glass tube fitted with a vycor tip) and was calibrated to be 0.32 V versus the normal hydrogen electrode using a ferrocene standard. The result of molecular weight, decomposition temperature (stability (degreesC)) and conductivity potential ((at 0.5M) (mS/cm)a)) of control/test was found to be 569.5/356.6, 400/465 and 4.6 /7.7 respectively.