Polytype and Stacking Faults in the Li2CoSiO4 Li‐Ion Battery Cathode |
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Authors: | Dr Quang Duc Truong Dr Murukanahally Kempaiah Devaraju Dr Yoshikazu Sasaki Dr Hiroshi Hyodo Prof Itaru Honma |
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Institution: | 1. Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2‐1‐1 Katahira, Aobaku, Sendai 980‐8577 (Japan);2. DATUM Solution Business Operations, JEOL Ltd., 1156 Nakagamicho, Akishima, Tokyo 196‐0022 (Japan) |
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Abstract: | Atomic‐resolution imaging of the crystal defects of cathode materials is crucial to understand their formation and the correlation between the structure, electrical properties, and electrode performance in rechargeable batteries. The polytype, a stable form of varied crystal structure with uniform chemical composition, holds promise to engineer electronic band structure in nanoscale homojunctions. 1 – 3 Analyzing the exact sites of atoms and the chemistry of the boundary in polytypes would advance our understanding of their formation and properties. Herein, the polytype and stacking faults in the lithium cobalt silicates are observed directly by aberration‐corrected scanning transmission electron microscopy. The atomic‐scale imaging allows clarification that the polytype is formed by stacking of two different close‐packed crystal planes in three‐dimensional space. The formation of the polytype was induced by Li–Co cation exchange, the transformation of one phase to the other, and their stacking. This finding provides insight into intrinsic structural defects in an important Li2CoSiO4 Li‐ion battery cathode. |
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Keywords: | crystal growth phase transitions polytypes silicates stacking interactions |
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