| 摘要 |
[Problem] To provide a lithium ion secondary battery which has excellent high-rate discharge characteristics. [Solution] A lithium ion secondary battery which comprises a positive electrode, a negative electrode and an electrolyte solution, and which is characterized in that the positive electrode uses a compound represented by formula (1) as a positive electrode active material and the electrode density of the positive electrode is 1.8-2.9 g/cm3. Lia(M)b(PO4)cXd (1) (In the formula, M represents VO or V; X represents F; and 0.9 ≤ a ≤ 3.3, 0.9 ≤ b ≤ 2.2, 0.9 ≤ c ≤ 3.3 and 0 ≤ d ≤ 1.1.) |
