离子
替代(逻辑)
氧化物
钠
无机化学
阴极
材料科学
化学
冶金
物理化学
计算机科学
有机化学
程序设计语言
作者
Yihao Shen,Chen Cheng,Xiangming Xiao,Lei Wang,Xi Zhou,Pan Zhang,Jianrong Zeng,Liang Zhang
标识
DOI:10.1016/j.jechem.2024.02.040
摘要
O3-type layered oxides have garnered great attention as cathode materials for sodium-ion batteries because of their abundant reserves and high theoretical capacity. However, challenges persist in the form of uncontrollable phase transitions and intricate Na+ diffusion pathways during cycling, resulting in compromised structural stability and reduced capacity over cycles. This study introduces a special approach employing site-specific Ca/F co-substitution within the layered structure of O3-NaNi0.5Mn0.5O2 to effectively address these issues. Herein, the strategically site-specific doping of Ca into Na sites and F into O sites not only expands the Na+ diffusion pathways but also orchestrates a mild phase transition by suppressing the Na+/vacancy ordering and providing strong metal-oxygen bonding strength, respectively. The as-synthesized Na0.95Ca0.05Ni0.5Mn0.5O1.95F0.05 (NNMO-CaF) exhibits a mild O3 → O3+O'3 → P3 phase transition with minimized interlayer distance variation, leading to enhanced structural integrity and stability over extended cycles. As a result, NNMO-CaF delivers a high specific capacity of 119.5 mA h g−1 at a current density of 120 mA g−1 with a capacity retention of 87.1% after 100 cycles. This study presents a promising strategy to mitigate the challenges posed by multiple phase transitions and augment Na+ diffusion kinetics, thus paving the way for high-performance layered cathode materials in sodium-ion batteries.
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