Zhan Jiajia, Huang Jiawen, Li Zhen, Yuan Jujun, Dou Shi-Xue, Liu Hua-Kun, Wu Chao
School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
Institute of Energy Materials Science (IEMS), University of Shanghai for Science and Technology, Shanghai 200093, China.
Nano Lett. 2024 Aug 14;24(32):9793-9800. doi: 10.1021/acs.nanolett.4c00968. Epub 2024 Aug 1.
O3-type layered oxides have been extensively studied as cathode materials for sodium-ion batteries due to their high reversible capacity and high initial sodium content, but they suffer from complex phase transitions and an unstable structure during sodium intercalation/deintercalation. Herein, we synthesize a high-entropy O3-type layered transition metal oxide, NaNiCuFeMnMgTiO (NCFMMT), by simultaneously doping Cu, Mg, and Ti into its transition metal layers, which greatly increase structural entropy, thereby reducing formation energy and enhancing structural stability. The high-entropy NCFMMT cathode exhibits significantly improved cycling stability (capacity retention of 81.4% at 1C after 250 cycles and 86.8% at 5C after 500 cycles) compared to pristine NaNiFeMnO (71% after 100 cycles at 1C), as well as remarkable air stability. Finally, the NCFMMT//hard carbon full-cell batteries deliver a high initial capacity of 103 mAh g at 1C, with 83.8 mAh g maintained after 300 cycles (capacity retention of 81.4%).
O3型层状氧化物因其高可逆容量和高初始钠含量，作为钠离子电池的阴极材料受到了广泛研究，但在钠嵌入/脱嵌过程中存在复杂的相变和不稳定结构。在此，我们通过将铜、镁和钛同时掺杂到其过渡金属层中，合成了一种高熵O3型层状过渡金属氧化物NaNiCuFeMnMgTiO（NCFMMT），这大大增加了结构熵，从而降低了形成能并增强了结构稳定性。与原始的NaNiFeMnO（1C下100次循环后容量保持率为71%）相比，高熵NCFMMT阴极表现出显著改善的循环稳定性（250次循环后1C下容量保持率为81.4%，500次循环后5C下容量保持率为86.8%）以及出色的空气稳定性。最后，NCFMMT//硬碳全电池在1C下具有103 mAh g的高初始容量，300次循环后保持83.8 mAh g（容量保持率为81.4%）。
