Patent ID: 7504181

Claim:
A non-polymerized nonaqueous liquid electrolyte having a viscosity at 20° C. of 60 cP to 30,000 cP comprising: a nonaqueous solvent containing 50-95% by volume y-butyrolactone,, an electrolyte dissolved in the nonaqueous solvent, and a macromolecular material added to the nonaqueous solvent comprising the structure represented by the formula: CH 2 —CH 2 —O n wherein n≧1, wherein the content of the macromolecular material added to the nonaqueous solvent is 0.01% or more, but less than 10% by weight; wherein the ratio p ranges from 0.001 to 0.05, wherein p=σ/η, and σ is the ion conductivity (10 −3 S/cm) and η is the viscosity (cP).