NONAQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD FOR PRODUCING SAME

A nonaqueous electrolyte secondary battery is provided, which includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and negative electrode, and an electrolyte solution containing a supporting salt having ion conductivity, wherein the positive electrode comprises a composition containing components (a) and (b) below and satisfying a requirement (±) below, and wherein the negative electrode contains metal lithium and at least one selected from materials capable of lithium ion insertion/desorption: (a) an electrically conductive polymer; (b) a lithium salt formed by substituting a part of a polyanionic acid with lithium; and (±) a molar ratio of a lithium element content in the component (b) to a content of an element involved in a charge/discharge reaction in the component (a) is 0.1 to 1.0. Consequently, the nonaqueous electrolyte secondary battery has an excellent weight energy density and can reduce dependency on electrolyte solution amount.