This application provides a nonaqueous electrolyte, a lithium-ion battery, a battery module, a battery pack, and an apparatus. The nonaqueous electrolyte includes a nonaqueous solvent, a lithium salt, and an additive. The nonaqueous solvent includes a carbonate solvent and a high oxidation potential solvent, and the additive is a fluorinated cyclic carbonate. The carbonate solvent is a linear carbonate, or a mixture of linear carbonate and cyclic carbonate, the high oxidation potential solvent is selected from one or more of compounds represented by formula I and formula II, and the fluorinated cyclic carbonate is selected from compounds represented by formula III. 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.