Lithium ion secondary battery

摘要

[Problem] To provide a lithium ion secondary battery having excellent high-rate discharge characteristics. [Solution] Excellent high-rate discharge characteristics are obtained by a lithium ion secondary battery in which a compound represented by Lia(NixCoyAl1-x-y)O2 (where 0.95≦a≦1.05, 0.5≦x≦0.9, 0.05≦y≦0.2, and 0.7≦x+y≦1.0) is used as a positive electrode active material in a positive electrode, the positive electrode has an electrode density of 3.75 to 4.1 g/cm3, and the positive electrode has a BET specific surface area of 1.3 to 3.5 m2/g as an electrode.

主权项

1. A lithium ion secondary battery comprising:
a positive electrode: a negative electrode; and an electrolyte solution, wherein the positive electrode uses a compound represented by a formula (1) as a positive electrode active material, the positive electrode has an electrode density of 3.75 to 4.10 g/cm3, the positive electrode has a positive electrode active material amount of 20 to 30 mg/cm2, the positive electrode has a pore volume of 0.005 to 0.02 cm3/g, and the positive electrode has a BET specific surface area of 1.3 to 3.5 m2/g as an electrode:
Lia(NixCoyAl1-x-y)O2  (1) where 0.95≦a≦1.05, 0.5≦x≦0.9, 0.05≦y≦0.2, and 0.7≦x+y≦1.0.