Mechanism exploration of enhanced electrochemical performance of single‐crystal versus polycrystalline LiNi 0.8 Mn 0.1 Co 0.1 O 2

Single‐crystal LiNi 0.8 Mn 0.1 Co 0.1 O 2 (SC‐811), which offers better cycle performance compared to the polycrystalline counterpart, has received great attention. We report herein the synthesis of SC‐811 with a grain size of 2–4 μm by washing and reheating method, which compares with conventional polycrystalline LiNi 0.8 Co 0.1 Mn 0.1 O 2 (PC‐811). The discharge capacity of SC‐811 reaches 152.1 mAh·g −1 after 100 cycles (86.7% capacity retention) at 1.0C, which is much better than that of PC‐811 (130.2 mAh·g −1 , 73.8% capacity retention). By using multiscale characterization, the results unveil that SC‐811 can not only improve the reversibility of the H2‐H3 phase transitions, suppress the generation of micro‐cracks and phase transformations, but also mitigate the undesired side reactions between electrode and electrolyte. Besides, the Li–O bond of SC‐811 is longer than that of PC‐811, which is conducive to the de‐intercalation of Li‐ions, thereby enhancing the structural stability. This finding provides an impressive strategy to sustain structural stability and improve the cycling life of Ni‐rich layered cathodes.