Zhang Yiming, Tang Dafu, Liu Yuanyuan, Wang Jin, Li Zhipeng, Li Xin, Han Guang, Wei Qiulong, Qu Baihua
Pen-Tung Sah Institute of Micro-Nano Science and Technology, College of Materials, Xiamen University, Xiamen, 361005, P. R. China.
College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, P. R. China.
Small. 2023 Aug;19(32):e2301141. doi: 10.1002/smll.202301141. Epub 2023 Apr 17.
Sodium-ion batteries (SIBs) are promising alternatives for large-scale energy storage owing to the rich resource and cost effectiveness. However, there are limitations of suitable low-cost, high-rate cathode materials for fast charging and high-power delivery in grid systems. Herein, a biphasic tunnel/layered 0.80Na MnO /0.20Na MnO (80T/20L) cathode delivering exceptional rate performance through subtly regulating the sodium and manganese stoichiometry is reported. It delivers a reversible capacity of 87 mAh g at 4 A g (33 C), much higher than that of tunnel Na MnO (72 mAh g ) and layered Na MnO (36 mAh g ). It proves that the one-pot synthesized 80T/20L is able to suppress the deactivation of L-Na MnO under air-exposure, which improves the specific capacity and cycling stability. Based on electrochemical kinetics analysis, the electrochemical storage of 80T/20L is mainly based on pseudocapacitive surface-controlled process. The thick film of 80T/20L cathode (a single-side mass loading over 10 mg cm ) also has superior properties of pseudocapacitive response (over 83.5% at a low sweep rate of 1 mV s ) and excellent rate performance. In this sense, the 80T/20L cathode with outstanding comprehensive performance could meet the requirements of high-performance SIBs.
钠离子电池（SIBs）因其资源丰富和成本效益高，是大规模储能的有前景的替代方案。然而，在电网系统中，用于快速充电和高功率输出的合适低成本、高倍率阴极材料存在局限性。在此，报道了一种双相隧道/层状的0.80NaMnO /0.20NaMnO（80T/20L）阴极，通过巧妙调节钠和锰的化学计量比实现了卓越的倍率性能。它在4 A g（33 C）下的可逆容量为87 mAh g，远高于隧道型NaMnO（72 mAh g）和层状NaMnO（36 mAh g）。证明了一锅法合成的80T/20L能够抑制L-NaMnO在空气暴露下的失活，从而提高比容量和循环稳定性。基于电化学动力学分析，80T/20L的电化学存储主要基于赝电容表面控制过程。80T/20L阴极的厚膜（单侧质量负载超过10 mg cm）也具有优异的赝电容响应特性（在1 mV s的低扫描速率下超过83.5%）和出色的倍率性能。从这个意义上说，具有出色综合性能的80T/20L阴极能够满足高性能钠离子电池的要求。
