This application provides a nonaqueous electrolyte, a lithium-ion battery, a battery module, a battery pack, and an apparatus. The nonaqueous solvent includes a nonaqueous solvent and a lithium slat. The nonaqueous solvent includes a carbonate solvent and a high oxidation potential solvent, and the high oxidation potential solvent is selected from one or more of compounds represented by formula I and formula II. Based on a total weight of the nonaqueous solvent, a weight percentage of the high oxidation potential solvent is 10% to 60%. This application can not only improve electrochemical performance of the lithium-ion battery under high temperature and high voltage and improve safety performance such as overcharge safety and hot box safety of the lithium-ion battery, but also ensure that the lithium-ion battery has some kinetic performance.