Patent ID: 7235335

Claim:
A secondary battery containing a nonaqueous liquid electrolyte having a viscosity within the range of 60 cP to 30,000 cP comprising: a positive electrode containing an active material, a negative electrode containing a material which absorbs and desorbs lithium ions, and a liquid electrolyte sandwiched between the positive and negative electrodes, wherein the liquid electrolyte comprises: a nonaqueous solvent containing γ-butyrolactone, an electrolyte dissolved in the nonaqueous solvent, and a macromolecular material, which is 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 and is sufficient to bring the viscosity of the nonaqueous liquid electrolyte at 20° C. within the range of 60 cP to 30,000 cP.