TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The anion is of formulae ((R1)(R2)N-), ((R1)(R2)(R3)(R4)(R5)(R6)X1-), ((R1)(R2)(R3)C-), or ((R1)(R2)(R3)(R4)B-), which include hexacyanophosphate(V) anion, hexacyano arsenate(V) anion, dicyanamide anion (preferred), tricyanomethyl anion or tetracyanoborate anion. The lithium mobile ions are provided by at least one lithium salt including lithium dicyanamide, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonylimide) or lithium hexafluorophosphate, where the lithium salt is present at 0.3-1 mol/kg, preferably 0.5 mol/kg. The cation counterion includes pyrrolidinium, piperazinium, piperidinium, di- or tri-substituted imidazolium or their phosphorus and arsenic derivatives, preferably 1,1-dialkyl-pyrrolidinium or N-butyl-N-methyl-pyrrolidinium. The positive electrode comprises: a lithium oxide material including lithium cobalt oxide, lithium-manganese dioxide, lithium dimanganese tetraoxide, lithium nickel manganese chromium oxide, lithium manganese nickel oxide, or their analogues, conducting polymers and/or redox conducting polymers; and a lithium metal phosphate, which is lithium iron phosphate. The negative electrode comprises a lithium titanium oxide material (Li4Ti5O12). The ionic liquid electrolyte comprises: at least one additional component including a room temperature ionic liquid, diluent, solid electrolyte interphase forming (SEI) additive (preferred), gelling additive or organic solvent; and a dicyanamide anion. The SEI forming additive includes: polymers comprising the electroconductive polymers (polyvinylpyrrolidone, polyethylene oxide, polyacrylonitrile, polyethylene glycols, glymes (tetraglyme) (preferred) or perfluorinated polymers); or salts including magnesium iodide, aluminum iodide, tin iodide, lithium iodide, tetraethylammonium heptadecafluoro octanesulfonate, dilithium phthalocyanine, lithium heptadecafluoro octanesulfonate or tetraethylammonium fluoride-tetrakis hydrogen fluoride. The electrolyte comprises water (50-500 ppm, preferably 200 ppm). The lithium energy storage device is operable over a temperature of 0-80 degrees C. The device is: a lithium metal energy storage device, where the negative electrode is a lithium metal negative electrode; or a lithium ion energy storage device, where the negative electrode comprises lithium titanium oxide (LiTi5O12).X1 = P or As;R1 = CN;R2-R6 = organic group including at least one of a halo, oxalate, tosylate, ether, ester, nitrile, sulfonyl, carbonyl or nitro group, preferably -CN, -F, -Cl, -(COO)2-, CmY1(2m+1)SO2-, CmY1(2m+1)SO3-, CmY1(2m+1)C6Y14SO2-, CmY1(2m+1)C6Y14SO3-, R7-SO2-, R7-SO3-, CmY1(2m+1)C(O)O-, CmY1(2m+1)O(O)C-, CmY1(2m+1)CY12O-, CY13O-, CmY1(2m+1)OCY12-, 2-6C alkenyl or -CN;Y1 = F or H;m = 1-6; andR7 = halo.