Xiao Ke, Zhao Bangchuan, Bai Jin, Mao Yunjie, Wang Peiyao, Wang Siya, Zhu Xuebin, Sun Yuping
Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei, 230031, People's Republic of China.
University of Science and Technology of China, Hefei, 230026, People's Republic of China.
Chemistry. 2024 Dec 10;30(69):e202402313. doi: 10.1002/chem.202402313. Epub 2024 Nov 3.
P2-type layered transition metal oxide NaNiMnO is considered as a promising cathode for advanced sodium-ion batteries due to its high theoretical specific capacity. However, the P2-type cathode suffers severe P2-O2 phase transition during cycling process, resulting unsatisfactory cyclic stability and rate capability. Herein, a Ca/Li co-doped P2-type NaCaNiMnLiO (NCNMLO) cathode material was synthesized through a simple sol-gel method. With the synergistic effect of Ca-doping at Na sites and Li substitution at transition metal (TM) sites, the cathode achieves an excellent electrochemical performance due to the inhibited P2-O2 phase transition and improved ion diffusion with Na/vacancy disordering arrangement. The NCNMLO cathode exhibits a good cyclic stability with 70.8 % of capacity retention at 1 C after 200 cycles and excellent rate capability with 40.1 mAh g at 20 C. The dual sites doping strategy provides an effective and simple approach for designing high-performance layered oxide cathode materials for sodium-ion batteries.
P2型层状过渡金属氧化物NaNiMnO由于其高理论比容量，被认为是一种有前景的先进钠离子电池正极材料。然而，P2型正极在循环过程中会发生严重的P2 - O2相变，导致循环稳定性和倍率性能不尽人意。在此，通过简单的溶胶 - 凝胶法合成了一种Ca/Li共掺杂的P2型NaCaNiMnLiO（NCNMLO）正极材料。由于Na位点的Ca掺杂和过渡金属（TM）位点的Li取代的协同作用，该正极由于抑制了P2 - O2相变以及通过Na/空位无序排列改善了离子扩散，从而实现了优异的电化学性能。NCNMLO正极表现出良好的循环稳定性，在200次循环后1 C下容量保持率为70.8%，并且在20 C下具有40.1 mAh g的优异倍率性能。双位点掺杂策略为设计用于钠离子电池的高性能层状氧化物正极材料提供了一种有效且简单的方法。
