Li Weiliang, Chen Guohu, He Guangpeng, Xie Junzhou, Liang Dan, Qiu Shiming, Li Chunliu, Wu Wenwei, Wu Xuehang
School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
Guangxi Key Laboratory for High-value Utilization of Manganese Resources, Chongzuo Key Laboratory of Comprehensive Utilization Technology of Manganese Resources, College of Chemistry and Biological Engineering, Guangxi Minzu Normal University, Chongzuo 532200, China.
J Colloid Interface Sci. 2025 Aug 15;692:137484. doi: 10.1016/j.jcis.2025.137484. Epub 2025 Mar 31.
Charging O3-type layered-oxide cathodes to a high cutoff voltage of 4.3 V (vs. Na/Na) can enhance the energy density of sodium-ion batteries (SIBs). However, the irreversible oxygen redox reaction at high voltages often leads accelerated capacity degradation. Herein, a series of Ga-doped O3-type NaZnNiGaMnTiO cathode materials are prepared, and the impact of Ga doping on their bulk/interface properties and electrochemical performance is systematically examined. Ga incorporation enhances the structural ordering of the layered framework and widens Na transport pathways, thereby reducing Na transport barrier. The Ga-doped material demonstrates superior structural reversibility and mechanical stability compared to the pristine counterpart during cycling. As evidenced by the density functional theory calculations, Ga doping modulates the O 2p state near the Fermi level, mitigating the charge compensation mechanism of lattice oxygen, oxygen vacancy formation, and electrolyte decomposition at high voltages. Consequently, within the voltage range of 2.2-4.3 V, NaZnNiGaMnTiO exhibits a higher capacity retention after 100 cycles at 100 mA g (86.4 % vs. 68.1 %) and better rate capability at 2000 mA g (94.1 mAh g vs. 80.0 mAh g) than NaZnNiMnTiO. This work provides valuable insights into the role of Ga in high-voltage O3-type layered oxides and offers guidance for the design of high-entropy cathode materials for SIBs.
将O3型层状氧化物阴极充电至4.3 V（相对于Na/Na）的高截止电压可提高钠离子电池（SIB）的能量密度。然而，高电压下不可逆的氧氧化还原反应往往会导致容量加速衰减。在此，制备了一系列Ga掺杂的O3型NaZnNiGaMnTiO阴极材料，并系统研究了Ga掺杂对其体相/界面性质和电化学性能的影响。Ga的掺入增强了层状骨架的结构有序性，拓宽了Na传输通道，从而降低了Na传输势垒。与原始材料相比，Ga掺杂材料在循环过程中表现出优异的结构可逆性和机械稳定性。密度泛函理论计算表明，Ga掺杂调节了费米能级附近的O 2p态，减轻了晶格氧的电荷补偿机制、氧空位形成以及高电压下的电解质分解。因此，在2.2-4.3 V的电压范围内，NaZnNiGaMnTiO在100 mA g下循环100次后表现出更高的容量保持率（86.4%对68.1%），在2000 mA g下表现出更好的倍率性能（94.1 mAh g对80.0 mAh g）。这项工作为Ga在高电压O3型层状氧化物中的作用提供了有价值的见解，并为SIBs高熵阴极材料的设计提供了指导。
