Non-aqueous electrolyte solution type lithium ion secondary battery

摘要

A lithium-ion secondary battery with excellent durability is provided using a two-phase coexisting compound as a positive electrode active material. This lithium-ion secondary battery is provided with an electrode body having a positive electrode containing a positive electrode active material and a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte solution containing a lithium salt in an organic solvent. The positive electrode active material is mainly composed of a two-phase coexisting compound containing lithium, and also contains particles of a lithium-transition metal oxide with a layered structure. The particles of the layered oxide have an average particle diameter of 2 μm or less, and the percentage content thereof in the positive electrode active material is 5 mass % or less.

主权项

1. A lithium-ion secondary battery comprising an electrode body having a positive electrode containing a positive electrode active material and a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte solution containing a lithium salt in an organic solvent,
wherein the positive electrode active material contains 95 mass % or more and 99.9 mass % or less of a two-phase coexisting compound containing lithium, and also contains 0.1 to 5 mass % of particles of a lithium-transition metal oxide with a layered structure, the two-phase coexisting compound is an olivine compound represented by the following General Formula (I):
LixFe1−yMyZO4  (I) wherein M is at least one selected from the group consisting of Mn, Mg, Ni, Co, Cu, Zn, Ge, Cr, V, Nb, Mo, Ti and Ga, Z is P or Si, x satisfies 0.05≦x≦1.2, and y satisfies 0≦y≦0.5, the layered lithium-transition metal oxide particles have a composition represented by the following General Formula (II):
LiNi0.3+mMn0.3+nCo0.4−m−nO2  (II) wherein m satisfies 0≦m≦0.4 and n satisfies 0≦n≦0.4, and the layered lithium-transition metal oxide particles have an average particle diameter of 0.1 μm to 2 μm.