TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Device: The electrolyte (E1) comprises the dinitrile and the co-solvent in a volume ratio of 1:9 to 9:1 (preferably 1:5 to 5:1) of dinitrile:co-solvent. The ionic salt is present in the electrolyte (E1) in an amount of 1-20 (preferably 2-12) mol%. In the device the anode comprises a lithium (Li)-containing material having an electrochemical potential within 2 (preferably 1.6, especially 1.3) V of lithium metal; and the cathode comprises LiCoO2, Li(Ni,Co)O2, LiMn2O4, Li(Mn0.5Ni0.5)O2, Li1+x(Mn,Ni)1-xO2, Li1+x(Mn,Ni,Co)1-xO2, LiNi0.5Mn1.5O4, LiFePO4, LiFe0.5Mn0.5PO4, LiMnPO4, LiNiPO4 and/or V2O5 (preferably LiCoO2, LiFePO4 or Li1.2Mn0.4Ni0.3Co0.1O2, especially LiNiPO4). Preferred Components: The ionic salt is a lithium-based salt selected from lithium bioxalato borate, lithium bis-trifluoromethanesulfonylimide, lithium bis-perfluoroethylsulfonylimide, lithium difluoro(oxalato)borate, lithium tetrafluoroborate, lithium hexafluorophosphate, LiPF3(CF2CF3)3, lithium thiocyanate, lithium triflate, lithium tetrafluoroaluminate, and/or lithium perchlorate. The Li-containing material is selected from lithium metal, lithium alloy, lithium intercalated into hard or soft carbon, lithium intercalated into oxide, nitride or phosphide, and/or lithium inserted into a compound or composite by displacement (preferably lithium metal, lithium intercalated into graphite or lithium titanate). The dinitrile is selected from succinonitrile, glutaronitrile, and/or adiponitrile (preferably succinonitrile or a mixture of succinonitrile and another dinitrile); where liquid dinitrile is a mixture of dinitrile and a co-solvent. The co-solvent is selected from organic carbonate, lactone, sulfone, nitrile, and/or ether such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate, propylene carbonate, methyl propyl carbonate, dimethyl formamide, tetrahydrofuran, 2-methyl tetrahydrofuran, 2-chloromethyl tetrahydrofuran, methyl formate, methyl acetate, gamma -butyrolactone, acetonitrile, 3-methoxypropionitrile, tetramethylene sulfone, dimethyl sulfoxide, tetraethylsulfonamide, dimethyl sulfite, sulfolane, 1,3-dioxolane, dimethoxyethane, sulfur dioxide, thionyl chloride, and/or sulfuryl chloride (preferably dimethyl carbonate, ethylene carbonate, and/or propylene carbonate). EXAMPLE - The electrolyte (control) comprising ( approximately 1 M) lithium bioxalato borate (LiBOB) (0.77 mol/kg) in ethylene carbonate (EC) (29.7 wt.%), ethyl acetate (EA) (38 wt.%) and gamma -butyrolactone (BL) (17 wt.%) was prepared. The electrolytes (test) was prepared similarly except that adiponitrile (ADN) was used in place of EA and BL. Both the electrolytes (test/control) were evaluated for oxidative stability, and thermal stability. The electrolyte (test) showed a wide electrochemical stability extending to values in excess of 6 V, where as the electrolyte (control) showed a stability of 5 V; and the electrolyte (control) started to evaporate at 150 degrees C, while the electrolyte (test) showed little evaporation and good stability up to 200 degrees C.