This standard establishes a unified testing method for evaluating the high-temperature electrochemical performance of lithium-ion battery cathode materials, systematically specifying the procedures and indicators for two core tests: high-temperature storage and high-temperature cycling. The standard covers various cathode materials, including lithium cobalt oxide and lithium iron phosphate, and accurately assesses their stability and safety under extreme conditions by testing parameters such as capacity retention rate, capacity recovery rate, and battery swelling rate at high temperatures. During the testing phase, a high-precision high-temperature test chamber is required to precisely control the test temperature (e.g., 60°C ± 2°C), and a battery testing system is used to continuously record charge and discharge data. Additionally, a thickness gauge or water displacement volume testing device is employed to monitor changes in battery thickness or volume to calculate the swelling rate. Furthermore, equipment such as a vacuum drying oven, coating machine, and rolling press are used in the preparation of cathode sheets to ensure the consistency of electrode quality. These precise testing methods provide technical support for the reliable evaluation of the high-temperature performance of materials.