The present application provides a lithium-ion battery and an apparatus. The lithium-ion battery includes an electrode assembly and an electrolytic solution. The electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separation film. A positive active material in the positive electrode sheet includes Lix1Coy1M1-y1O2-z1Qz1. A negative active material in the negative electrode sheet includes one or more of Si, SiOx2, a Si/C composite material, and a Si alloy. The electrolytic solution contains an additive A and an addictive B, the additive A is a polynitrile six-membered nitrogen-heterocyclic compound with a relatively low oxidation potential, and the additive B is a halogen-substituted cyclic carbonate compound. The lithium-ion battery has superb cycle performance and storage performance, especially under high-temperature and high-voltage conditions.