An electrochemical apparatus including a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode includes a positive electrode current collector and a positive active material layer disposed on the positive current collector. An X-ray photoelectron spectroscopy of the positive active material layer has a peak at 164 eV to 175 eV. The electrolyte has a retention capability of 1.0 g/Ah to 4.0 g/Ah. The electrolyte improves cycle performance, over-discharge storage performance, and safety performance of the electrochemical apparatus.