Understanding and Controlling Structural Defects and Disordering in LiNi<sub>0.5</sub>Mn<sub>1.5</sub>O<sub>4</sub> Cathodes for Direct Recycling
Hongpeng Gao, Bing Han, Duc Tran, Luqi Zhang, Zishuo Zhao, Yu‐Ting Chen, Wei Tang, Mingjie Xu, Junlin Wu, Xiaolu Yu, Varun Gupta, Maura Appleberry, Haodong Liu, Yijie Yin, Weiliang Yao, M. Li, Weikang Li, Linqin Mu, Ying Shirley Meng, Zheng Chen
Abstract
Despite significant progress in recycling spent lithium-ion batteries (LIBs), nondestructive, direct recycling methods still face untenable discrepancies in multiple cathode chemistries, which primarily originate from a variety of structure stabilities during the recycling process. Through systematic investigation of the microstructure evolution during the relithiation treatment, we observed the inevitably induced defects and Li/Mn disordering in the LiNi 0.5 Mn 1.5 O 4 cathode, contributing to the sluggish Li + transport and irreversible capacity loss. Employing a defect engineering approach to achieve twin boundaries and preferred grain orientation, we show the regenerated cathodes demonstrate a substantial enhancement of Li + diffusion and cycling stability, retaining 97.4% capacity after 100 cycles and 87.96% after 200 cycles at C/3. This work not only elaborates on a systematic investigation of defect inducement and structural restoration mechanism but also provides an effective approach to directly recycle high-voltage spinel-type cathodes, contributing to the sustainability of next-generation LIBs.