Gao Mingyang, Li Huijun, Zhao Zhenxin, Wang Xiaomin
College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
ACS Appl Mater Interfaces. 2024 Mar 27;16(12):14789-14798. doi: 10.1021/acsami.3c18341. Epub 2024 Mar 14.
The P2-layered metal oxide cathode materials are crucial for constructing high-rate sodium-ion batteries (SIBs); however, its practical application is hindered by the high Na diffusion barrier resulting from Na/vacancy ordering. Herein, a Li/Zn cosubstitution P2-NaNiMnO (NLNZM) cathode was synthesized via a sol-gel method assisted with citric acid, which can induce the rearrangement of Na sites to disrupt ordered structures. The XRD Rietveld refinement confirms a higher occupancy of Na at Na sites with low diffusion barriers through the Li/Zn cosubstitution. In addition, the highly reversible phase evolution of the NLNZM is confirmed through in situ XRD results, thereby ensuring the stability of the structure with low volume change rate (0.78%). Furthermore, Li and Zn can reduce the surface energy and increase the interlayered distance to achieve rapid interfacial kinetics. As a result, the NLNZM has exhibited a high reversible capacity of 152.8 mAh g and an outstanding rate performance of 103.4 mAh g at 5C. After 200 cycles at 5C, the capacity retention rate is 81.1%. This work proposes a cosubstitution strategy to induce Na/vacancy disorder for achieving rapid Na migration as a cathode material for SIBs.
P2 层状金属氧化物阴极材料对于构建高倍率钠离子电池（SIBs）至关重要；然而，由于 Na/空位有序化导致的高 Na 扩散势垒阻碍了其实际应用。在此，通过柠檬酸辅助的溶胶 - 凝胶法合成了一种 Li/Zn 共取代的 P2 - NaNiMnO（NLNZM）阴极，该方法可诱导 Na 位点重排以破坏有序结构。XRD 全谱拟合证实，通过 Li/Zn 共取代，Na 在具有低扩散势垒的 Na 位点上占有率更高。此外，原位 XRD 结果证实了 NLNZM 具有高度可逆的相演变，从而确保了结构的稳定性，体积变化率低（0.78%）。此外，Li 和 Zn 可以降低表面能并增加层间距，以实现快速的界面动力学。结果，NLNZM 展现出 152.8 mAh g 的高可逆容量以及在 5C 下 103.4 mAh g 的出色倍率性能。在 5C 下循环 200 次后，容量保持率为 81.1%。这项工作提出了一种共取代策略，以诱导 Na/空位无序化，从而实现快速的 Na 迁移，作为 SIBs 的阴极材料。
