Positive electrode composite material for lithium ion secondary battery and use thereof

Abstract

A positive electrode composite material for a lithium ion secondary battery that makes it possible to appropriately reduce the electric resistance in a positive electrode and to realize a high-performance lithium ion secondary battery. The positive electrode composite material to be used in the positive electrode of the lithium ion secondary battery includes a particulate positive electrode active material composed of a lithium composite oxide having a layered crystal structure including at least lithium, and a conductive oxide. Here, a particulate region where primary particles of the conductive oxide are aggregated, and a film-shaped region where the conductive oxide is formed in a film shape adhere to at least a part of the surface of the positive electrode active material. The average particle diameter based on cross-sectional TEM observation of primary particles in the particulate region is equal to or greater than 0.3 nm, and in cross-sectional TEM observation of the film-shaped region, no particles with a particle diameter equal to or greater than 0.3 nm are observed, and there are no voids equal to or greater than 2 nm.

Dependencies are inferred from the claim text.