Patent ID: 8163425

Claim:
A secondary battery comprising: a positive electrode; a negative electrode; a porous electron-insulating layer adhered to a surface of at least one selected from the group consisting of said positive electrode and said negative electrode; and an electrolyte, wherein said porous electron-insulating layer comprises a particulate filler and a resin binder, and said particulate filler substantially comprises indefinite-shape particles, wherein said indefinite-shape particles comprise a plurality of single crystalline primary particles, said single crystalline primary particles having a mean particle size of 0.1 to 1.0 μm, bonded to each other and a neck formed, by partially melting said plurality of single crystalline primary particles, between at least a pair of said single crystalline primary particles that are joined to one another, said neck comprising the same material as said single crystalline primary particles, wherein said indefinite-shape particles comprise a metal oxide.