Lithium secondary battery positive electrode and lithium secondary battery

摘要

A lithium secondary battery positive electrode according to the present invention is a lithium secondary battery positive electrode including a positive electrode material mixture layer containing a positive electrode active material and a conductivity enhancing agent on one or both sides of a current collector, wherein the positive electrode active material contains a lithium-containing composite oxide, the conductivity enhancing agent contains carbon fibers having an average fiber length of 10 nm or more and less than 1000 nm and an average fiber diameter of 1 nm or more and 100 nm or less, and the content of the carbon fibers in the positive electrode material mixture layer is 0.25 mass % or more and 1.5 mass % or less.

主权项

1. A lithium secondary battery positive electrode comprising a positive electrode material mixture layer containing a positive electrode active material and a conductivity enhancing agent on one or both sides of a current collector,
wherein the positive electrode active material contains a lithium-containing composite oxide, the conductivity enhancing agent contains carbon fibers having an average fiber length of 10 nm or more and less than 1000 nm and an average fiber diameter of 1 nm or more and 100 nm or less, the content of the carbon fibers in the positive electrode material mixture layer is 0.25 mass % or more and 1.5 mass % or less and the carbon fibers are dispersed in the positive electrode material mixture layer, the positive electrode active material contains a layer-structured lithium-containing composite oxide represented by the general compositional formula: Li1+xMO2, where x is within a range of −0.15 ≦x ≦0.15, and M represents an element group of three or more elements including at least Ni, Co and Mn, and the ratios of Ni, Co and Mn to the total elements constituting M satisfy 45≦a≦90, 5≦b≦30, 5≦c≦30 and 10≦b+c≦55, where the ratios of Ni, Co and Mn are represented by a, b and c, respectively, in units of mol %.