Parasitic structure defect blights sustainability of cobalt-free single crystalline cathodes

• Published in: Nature communications Vol. 16; no. 1; pp. 434 - 12
• Main Authors: Yu, Lei, Dai, Alvin, Zhou, Tao, Huang, Weiyuan, Wang, Jing, Li, Tianyi, He, Xinyou, Ma, Lu, Xiao, Xianghui, Ge, Mingyuan, Amine, Rachid, Ehrlich, Steven N., Ou, Xing, Wen, Jianguo, Liu, Tongchao, Amine, Khalil
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 06.01.2025; Nature Publishing Group; Nature Portfolio
• Subjects: 147/135; 147/143; 639/4077/4079; Cathodes; Cobalt; Crystal defects; Degradation; Diffusion layers; Electric potential; Electrochemical analysis; Electrochemistry; Electrode materials; Energy storage; High temperature; Humanities and Social Sciences; Imaging techniques; Lattice strain; Lithium; Lithium-ion batteries; MATERIALS SCIENCE; multidisciplinary; Polycrystals; Science; Science (multidisciplinary); Sustainability; Transition metal oxides; Voltage
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-55235-5

Recent efforts to reduce battery costs and enhance sustainability have focused on eliminating Cobalt (Co) from cathode materials. While Co-free designs have shown notable success in polycrystalline cathodes, their impact on single crystalline (SC) cathodes remains less understood due to the significantly extended lithium diffusion pathways and the higher-temperature synthesis involved. Here, we reveal that removing Co from SC cathodes is structurally and electrochemically unfavorable, exhibiting unusual voltage fade behavior. Using multiscale diffraction and imaging techniques, we identify lithium-rich nanodomains (LRNDs) as a heterogeneous phase within the layered structure of Co-free SC cathodes. These LRNDs act as critical tipping points, inducing significant chemo-mechanical lattice strain and irreversible structural degradation, which exacerbates the voltage and capacity loss in electrochemical performance. Our findings highlight the considerable challenges of developing Co-free SC cathodes compared to polycrystalline ones and emphasize the need for new strategies to balance the interplay between cost, sustainability, and performance. In Li-ion batteries, single crystalline cobalt-free lithium transition metal oxides are less understood than their polycrystalline counterparts. Here, authors show that the absence of cobalt in single crystalline oxides results in structural degradation that ultimately degrades battery performance.