Zhao Yanshuang, Lu Di, Yun XiaoRu, Wang Jinhui, Song Wenjin, Xie Wei, Zuo LanLan, Zheng Chunman, Xiao Peitao, Chen Yufang
College of Aerospace Science and Engineering, National University of Defense Technology, Changsha, 410073, China.
Small Methods. 2025 Apr;9(4):e2401221. doi: 10.1002/smtd.202401221. Epub 2024 Sep 18.
Regulating the distribution of surface elements in lithium-rich cathode materials can effectively change the electrochemical performance of cathode materials. Considering that the enrichment of Mn element on the surface is the main reason for the irreversible phase transition and dissolution of its surface structure, which in turn is the main reason for performance degradation. Based on the molten salt-assisted sintering method, a lithium rich cathode material with surface rich Ni and Co is designed and prepared. The surface enrichment of Ni and Co effectively reduces the dissolution of Mn, promotes the occurrence of irreversible collapse of surface structure from layered phase to rock salt phase on the material surface, improves the stability of surface crystal phase structure, and improves the cycling stability of positive electrode materials. Notably, after 500 cycles at 1 C current density, the discharge-specific capacity attained 189.8 mAh g , with a capacity retention rate of 88.9%, indicating a 42.1% improvement in capacity retention. Molten salt treatment is widely used in the modification of positive electrode materials. The research work will provide new ideas for improving the stability of lithium rich materials and promoting their commercial applications.
调控富锂正极材料表面元素分布可有效改变正极材料的电化学性能。鉴于表面Mn元素的富集是其表面结构发生不可逆相变和溶解的主要原因，而这又是性能退化的主要原因。基于熔盐辅助烧结法，设计并制备了一种表面富含Ni和Co的富锂正极材料。Ni和Co的表面富集有效降低了Mn的溶解，促进了材料表面从层状相向岩盐相的不可逆表面结构坍塌的发生，提高了表面晶相结构的稳定性，进而提高了正极材料的循环稳定性。值得注意的是，在1 C电流密度下循环500次后，放电比容量达到189.8 mAh g，容量保持率为88.9%，表明容量保持率提高了42.1%。熔盐处理在正极材料改性中得到广泛应用。该研究工作将为提高富锂材料的稳定性并促进其商业应用提供新思路。
