Patent ID: 8822072

Claim:
A nonaqueous electrolyte comprising: a solvent; at least one heteropolyacid salt compound; and an electrolyte salt other than the heteropolyacid salt compound, wherein at least one of said heteropolyacid salt compounds is represented by the following formulae (I) and (II) H x A y [BD 12 O 40 ].zH 2 O (I) wherein A represents lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ca), aluminum (Al), ammonium (NH 4 ), an ammonium salt or a phosphonium salt; B represents phosphorus (P), silicon (Si), arsenic (As) or germanium (Ge); D represents at least one element selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), rhodium (Rh), cadmium (Cd), indium (In), tin (Sn), tantalum (Ta), tungsten (W), rhenium (Re) and thallium (Tl); and x, y and z are values falling within the ranges of (0≦x≦1), (2≦y≦4) and (0≦z≦5), respectively, and H p A q [B 5 D 30 O 110 ].rH 2 O (II) wherein A represents lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), magnesium (Mg), calcium (Ca), aluminum (Al), ammonium (NH 4 ), an ammonium salt or a phosphonium salt; B represents phosphorus (P), silicon (Si), arsenic (As) or germanium (Ge); D represents at least one element selected from the group consisting of titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), rhodium (Rh), cadmium (Cd), indium (In), tin (Sn), tantalum (Ta), tungsten (W), rhenium (Re) and thallium (Tl); and p, q and r are values falling within the ranges of (0≦p≦5), (10≦q≦15) and (0≦r≦15), respectively, and wherein an amount of acid component in the nonaqueous electrolyte solution is not more than 100 ppm.