Abstract: Disclosed is an electricity storage device which can be charged/discharged at high rate and have high output, high capacity and excellent repeating charge/discharge characteristics, although it uses a non-carbon material as a negative electrode active material. Specifically disclosed is an electricity storage device comprising: a positive electrode collector; a positive electrode disposed on the positive electrode collector and including a positive electrode active material which can reversibly absorb/desorb at least anions; a negative electrode collector; and a negative electrode disposed on the negative electrode collector and including a negative electrode active material which can substantially absorb/desorb lithium ions reversibly.

Abstract: A power storage device of the present invention includes a positive electrode, a negative electrode, and an electrolyte. At least one of the positive electrode and the negative electrode includes an organic compound as an active material having a portion contributing to an oxidation-reduction reaction. The organic compound is crystalline in both a charged state and a discharged state.

Abstract: A method for producing a secondary cell according to the present invention includes step (A) of putting a solution having an electrochemically reversibly oxidizable/reducible organic compound and a supporting electrolyte dissolved therein into contact with a positive electrode active material, thereby oxidizing or reducing the positive electrode active material; and step (B) of accommodating the oxidized positive electrode active material and a negative electrode active material in a case in the state of facing each other with a separator being placed therebetween, and filling the case with an electrolyte solution. By oxidizing or reducing the positive electrode active material, lithium ions or anions as the support electrode are incorporated into the positive electrode active material.