| UNDERSTANDING HIGH-TEMPERATURE CYCLING-INDUCED CRACK EVOLUTION AND ASSOCIATED ATOMIC-SCALE STRUCTURE IN A NI-RICH LiNi0.8Co0.1Mn0.1O2 LAYERED CATHODE MATERIAL Xuejie Huang1; Feng Tian1; Hailong Yu1; Hongxiang Ji1; Wenwu Zhao1; Zhongzhu Liu2; Robson Monteiro3; Rogerio Ribas3; Yongming Zhu4; Xuejie Huang5; 1SONGSHAN LAKE MATERIALS LABORATORY, Dongguan, China; 2CITC-METAL, Beijing, China; 3COMPANHIA BRASILEIRA DE METALURGIA E MINERAçãO, Araxá/Minas Gerais, Brazil; 4HARBIN INSTITUTE OF TECHNOLOGY AT WEIHAI, Weihai, China; 5SONGSHAN LAKE MATERIALS LAB, Dongguan, China; PAPER: 483/Battery/Keynote (Oral) SCHEDULED: 14:50/Tue. 29 Nov. 2022/Similan 2 ABSTRACT: With the increasing demand for advanced energy storage devices in portable electronics and electrical vehicles, nikel-rich LiNixCoyMn1-x-yO2 (with x ≥ 0.8) layered cathode materials, which are low cost, have low toxicity, high practical specific capacity (> 200 mAh/g), and a relatively high operating voltage, are attracting increasing attention for their promising applications in next-generation cathode materials.[1] However, Ni-rich cathode materials have poor electrochemical performance, particularly during cycling at elevated temperatures, which significantly limits their application.<br />X-ray nano-computed tomography (nano-CT) and deep learning combined with Cs- corrected scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy were employed to investigate the atomic to microscopic structural evolution of LiNi0.8Co0.1Mn0.1O2 (NCM) upon cycling at 55 ◦C.[2] Two types of intergranular cracks were clearly distinguished by nano-CT for cycled cathode particles; denoted open and closed cracks depending on whether or not the cracks reach the surface of the NCM secondary particles. The volume of high-temperature cycling-induced cracks quantified by deep learning increased drastically, particularly for the open cracks, and this phenomenon was accompanied by rapid degradation of capacity retention. Further precise STEM analysis of the crack regions revealed that<br />migration of transition metal (TM) ions to the Li layer forms a rocksalt-like structure, and the associated reduction of TM ions, e.g., Ni3+ to Ni2+, predominately occurred in the open crack regions in the presence of penetrated electrolyte, even for regions extending to the center of the secondary particle. In contrast, in the closed crack regions, no significant atomic-scale structure distortion and limited reduction of TM<br />ions was observed. References: [1] H. Ji, L. Ben, X. Huang, et al, Electrolyzed Ni(OH)2 Precursor Sintered with LiOH/LiNiO2 Mixed Salt for Structurally and Electrochemically Stable Cobalt-Free LiNiO2 Cathode Materials ACS Applied Materials & Interfaces, 2021, 13, 50965-50974.<br /> <br />[2] F. Tian, L. Ben, X. Huang et al, Understanding high-temperature cycling-induced crack evolution and associated atomic-scale structure in a Ni-rich LiNi0.8Co0.1Mn0.1O2 layered cathode material. Nano Energy, 2022, 98, 107222-<br />107235 |
