Perspective on low-temperature electrolytes for LiFePO₄-based lithium-ion batteries

The olivine-type lithium iron phosphate (LiFePO₄) cathode material is promising and widely used as a high-performance lithium-ion battery cathode material in commercial batteries due to its low cost, environmental friendliness, and high safety. At present, LiFePO₄/C secondary batteries are widely used for electronic products, automotive power batteries, and other occasion-related applications with good thermal stability, stable cycle performance, and low room-temperature self-discharge rate. However, LiFePO₄-based battery applications are seriously limited when they are operated in a cold climate. This outcome is due to a considerable decrease in Li⁺ transport capabilities within the electrode, particularly leading to a dramatic decrease in the electrochemical capacity and power performance of the electrolyte. Therefore, the design of low-temperature electrolytes is important for the further commercial application of LiFePO₄ batteries. This paper reviews the key factors for the poor low-temperature performance of LiFePO₄-based batteries and the research progress of low-temperature electrolytes. Special attention is paid to electrolyte components, including lithium salts, cosolvents, additives, and the development of new electrolytes. The factors affecting the anode are also analyzed. Finally, according to the current research progress, some viewpoints are summarized to provide suitable modification methods and research suggestions for improving the practicability of LiFePO₄/C commercial batteries at low temperatures in the future.