ELECTROLYTE FOR POWER STORAGE DEVICES AND NONAQUEOUS ELECTROLYTE SOLUTION

To provide an electrolyte for a storage device capable of lowering the electric resistance and maintaining a high capacity even after charging and discharging are repeatedly carried out, and a storage device.An electrolyte for a storage device, which comprises a lithium-containing complex compound represented by the following formula (1), (2), (3), (4) or (5): (Li)m (A)n (UFx)y (1) (Li)m (Si)n (O)q (UFx)y (2)wherein A is O, S, P or N; U is a boron atom or a phosphorus atom; m and n are each independently from 1 to 6; q is from 1 to 12; x is 3 or 5; and y is from 1 to 6; (Li)m (O)n (B)p (OWFq)x (3)wherein W is a boron atom or a phosphorus atom; m, p and x are each independently from 1 to 15; n is from 0 to 15; and q is 3 or 5; (Li)m (B)n (O)n (OR)y (OWFq)x (4)wherein W is a boron atom or a phosphorus atom; n is from 0 to 15; p, m, x and y are each independently from 1 to 12; q is 3 or 5; and R is hydrogen, an alkyl group, an alkenyl group, an aryl group, a carbonyl group, a sulfonyl group or a silyl group, and such a group may have a fluorine atom, an oxygen atom or other substituent; (Li)m (O)n (B)p (OOC-(A)z -COO)y (OWFq)x (5)wherein W is a boron atom or a phosphorus atom, A is a C1-6 allylene group, alkenylene group or alkynylene group, a phenylene group, or an alkylene group having an oxygen atom or a sulfur atom in its main chain; m, p, x and y are each independently from 1 to 20; n is from 0 to 15; z is 0 or 1; and q is 3 or 5.