Electrode mixture paste for sodium secondary cell, positive electrode for sodium secondary cell, and sodium secondary cell

Abstract

An electrode mixture paste for a sodium secondary battery contains a positive electrode active material capable of being doped and dedoped with a sodium ion, an electroconductive material, a binder, an organic solvent and an acid having a valence number of 2 or more. The electrode mixture paste for a sodium secondary battery gives little change in viscosity with lapse of time even when there are no special facilities.

1 . An electrode mixture paste for a sodium secondary battery, containing a positive electrode active material that is doped and undoped with a sodium ion, an electroconductive material, a binder, an organic solvent, and an acid having a valence number of 2 or more. 
     
     
         2 . The electrode mixture paste for a sodium secondary battery according to  claim 1 , wherein said acid having a valence number of 2 or more is an organic acid. 
     
     
         3 . The electrode mixture paste for a sodium secondary battery according to  claim 2 , wherein said organic acid is oxalic acid, malic acid, or succinic acid. 
     
     
         4 . The electrode mixture paste for a sodium secondary battery according to  claim 1 , wherein said acid having a valence number of 2 or more is an inorganic acid. 
     
     
         5 . The electrode mixture paste for a sodium secondary battery according to  claim 4 , wherein said inorganic acid is phosphoric acid, boric acid, or sulfuric acid. 
     
     
         6 . A positive electrode for a sodium secondary battery which is formed by applying an electrode mixture paste for a sodium secondary battery according to  claim 1  onto a current collector and drying the resultant. 
     
     
         7 . A sodium secondary battery comprising a positive electrode for a sodium secondary battery according to  claim 6 , a negative electrode containing a negative electrode active material that is doped and undoped with a sodium ion, and an electrolyte.