Abstract: This application provides a nonaqueous electrolytic solution, a lithium-ion battery, a battery module, a battery pack, and an apparatus. The nonaqueous electrolytic solution includes a nonaqueous solvent and a lithium salt. The nonaqueous solvent includes a carbonate solvent and a high-oxidation-potential solvent. The carbonate solvent is a mixture of a cyclic carbonate and a chain carbonate, and the high-oxidation-potential solvent is selected from one or more of compounds denoted by Formula I and Formula II. This application improves electrochemical performance of the lithium-ion battery under a high temperature and a high voltage as well as safety performance such as overcharge safety and hot-oven safety of the lithium-ion battery, and also ensures kinetic performance of the lithium-ion battery to some extent.