Mechanistic Investigation of Capacity Degradation in Lithium Iron Phosphate Batteries under Low Temperature Cycling Conditions

Since lithium-ion batteries have been put into use, the recession of work cycle efficiency at low temperatures has received widespread attention. In this paper, we investigated the effect of low temperature (−5°C, 0°C, 5°C) environments on the performance of lithium-ion batteries, which are well-known for their excellent discharge performance, cycle life, and safety. However, lithium-ion batteries exhibit significant capacity degradation at low temperatures, especially at 0°C, losing availability after only 10 cycles. Therefore, we conducted cycle degradation tests at 1C discharge and 100% charge-discharge conditions. In this paper, we analyzed the surface morphology, structure, and elemental composition of the positive and negative electrodes before and after the aging process by disassembling them into half-cells and using three physical characterization techniques: scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Our study identifies the temperature range for accelerated aging, which provides guidance for the optimal use of lithium-ion batteries in low temperature environments, thus contributing to the rational utilization and enhanced the performance of lithium-ion batteries at low temperatures.