Native lattice strain induced structural earthquake in sodium layered oxide cathodes

• Published in: Nature communications Vol. 13; no. 1; pp. 436 - 12
• Main Authors: Xu, Gui-Liang, Liu, Xiang, Zhou, Xinwei, Zhao, Chen, Hwang, Inhui, Daali, Amine, Yang, Zhenzhen, Ren, Yang, Sun, Cheng-Jun, Chen, Zonghai, Liu, Yuzi, Amine, Khalil
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27-01-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 140/146; 147/143; 639/301/299/891; 639/4077/4079/891; Batteries; Cathodes; Crystal defects; Crystallography; Cycles; Deformation effects; Degradation; Discharge; Earthquakes; Electrode materials; Electron microscopy; High voltages; Humanities and Social Sciences; Interface reactions; Lattice strain; Microscopy; multidisciplinary; Phase transitions; Probes; Science; Science (multidisciplinary); Seismic activity; Sodium; Sodium channels (voltage-gated); Stacking faults; Synchrotron radiation; Synchrotrons; Synthesis; Transmission electron microscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-28052-x

High-voltage operation is essential for the energy and power densities of battery cathode materials, but its stabilization remains a universal challenge. To date, the degradation origin has been mostly attributed to cycling-initiated structural deformation while the effect of native crystallographic defects induced during the sophisticated synthesis process has been significantly overlooked. Here, using in situ synchrotron X-ray probes and advanced transmission electron microscopy to probe the solid-state synthesis and charge/discharge process of sodium layered oxide cathodes, we reveal that quenching-induced native lattice strain plays an overwhelming role in the catastrophic capacity degradation of sodium layered cathodes, which runs counter to conventional perception—phase transition and cathode interfacial reactions. We observe that the spontaneous relaxation of native lattice strain is responsible for the structural earthquake (e.g., dislocation, stacking faults and fragmentation) of sodium layered cathodes during cycling, which is unexpectedly not regulated by the voltage window but is strongly coupled with charge/discharge temperature and rate. Our findings resolve the controversial understanding on the degradation origin of cathode materials and highlight the importance of eliminating intrinsic crystallographic defects to guarantee superior cycling stability at high voltages.
Native crystallographic defects are often introduced during synthesis of battery materials, but has been overlooked. Here, using in situ synchrotron X-ray probes and electron microscopy, the authors have revealed their adverse effect during battery operation.