High Electrochemical Performance Recycling Spent LiFePO<sub>4</sub> Materials through the Preoxidation Regeneration Strategy
Xiangnan Li, Qibin Zhou, Xiaoyuan Zhang, Ming Ge, Huishuang Zhang, Yanhong Yin, Shuting Yang
Abstract
Recycling and regenerating spent lithium-ion batteries are significant in addressing raw material shortages and environmental issues. LiFePO 4 (LFP) has been widely used for its stability and economy. However, considering the production cost of LFP, the traditional metallurgy method is unsuitable for LFP recycling due to its cumbersome nature and high energy consumption. Meanwhile, direct regeneration of LFP is mostly adopted in materials with slightly degraded electrochemical properties. There is no making without breaking. Herein, the preoxidized strategy for regenerating spent LFP (SLFP) is reported. Specifically, by combining the oxidation removal of impurities and the solid-phase method, we have successfully restored SLFP with severely degraded electrical properties. At the same time, the physical and electrochemical properties of preoxidized LFP (RLFP) and directly regenerated LFP are compared. The results show that the SLFP materials are adequately decomposed by preoxidized regeneration technology. The subsequent addition of glucose not only reduced Fe 3+ but also enhanced the material’s conductivity as a uniform carbon layer. Then, Ti-doping is applied to improve the ionic conductivity of preoxidation-regenerated LFP material, and the rate performance of RLFP material is improved effectively. Compared with traditional methods, this technique is simple and has better environmental benefits. It provides a new possibility for the recycling of LFP materials.