Kang Wenpei, Ma Ping, Liu Zhanning, Wang Yuyu, Wang Xiaotong, Chen Huang, He Tinglei, Luo Weicong, Sun Daofeng
School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, P. R. China.
College of Science, China University of Petroleum (East China), Qingdao, Shandong 266580, P. R. China.
ACS Appl Mater Interfaces. 2021 Apr 7;13(13):15333-15343. doi: 10.1021/acsami.1c02216. Epub 2021 Mar 26.
As an important cathode candidate for the high-performance sodium ion batteries (SIBs), P2-type oxides with layered structures are needed to balance the specific capacities and cycling stability. As a result, a cation and anion codoped strategy has been adopted to tune the electrochemical activity of the redox centers and modulate the structure properties. Herein, a series of P2-NaMnNiOF ( = 0, 0.03, 0.05, and 0.07) cathodes with microsphere structures are synthesized, using a solid-state reaction in the presence of MnO microsphere self-templates. Compared with the cation-doped NaMnNiO, additional F-doping can affect the lattice parameters and redox centers of NaMnNiOF. Comprehensively considering the specific capacities, cycling stability, and rate capability, the optimized x value in NaMnNiOF is determined to be 0.05. In the half cells, NaMnNiOF (F-0.05) maintains a capacity of 90.5 mA h g in the first cycle at 1.0 A g, giving a capacity retention of 78% within 900 cycles. The superior rate capability of F-0.05 is guaranteed by the larger diffusion coefficient of Na () combined with higher charge transfer speed. In addition, when coupled with MoSe/PC anodes, the full cells also exhibit impressive electrochemical performance.
作为高性能钠离子电池（SIBs）的重要阴极候选材料，具有层状结构的P2型氧化物需要平衡比容量和循环稳定性。因此，采用了阳离子和阴离子共掺杂策略来调节氧化还原中心的电化学活性并调控结构性能。在此，利用MnO微球自模板存在下的固态反应，合成了一系列具有微球结构的P2-NaMnNiOF（x = 0、0.03、0.05和0.07）阴极。与阳离子掺杂的NaMnNiO相比，额外的F掺杂会影响NaMnNiOF的晶格参数和氧化还原中心。综合考虑比容量、循环稳定性和倍率性能，确定NaMnNiOF中优化的x值为0.05。在半电池中，NaMnNiOF（F-0.05）在1.0 A g下的首次循环中保持90.5 mA h g的容量，在900次循环内容量保持率为78%。F-0.05优异的倍率性能由更大的Na⁺扩散系数和更高的电荷转移速度保证。此外，当与MoSe₂/PC阳极耦合时，全电池也表现出令人印象深刻的电化学性能。
