Electrochemical Performance Optimization of Layered P2-Type Na0.67MnO2 through Simultaneous Mn-Site Doping and Nanostructure Engineering
Electrochemical Performance Optimization of Layered P2-Type Na0.67MnO2 through Simultaneous Mn-Site Doping and Nanostructure Engineering
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通过同时 Mn 位掺杂和纳米结构工程优化层状 P2 型 Na0.67MnO2 的电化学性能
DOI：
10.1002/batt.201900126
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发表时间：
2020
影响因子：
5.7
通讯作者：
Zhang Genqiang
中科院分区：
文献类型：
--
作者：
Peng Bo;Sun Zhihao;Jiao Shuhong;Wang Gongrui;Zhang Genqiang
钠离子电池因其成本低得多且能量密度与锂离子电池相当的独特特性而被认为是电网级储能应用最有前途的候选者。然而，由于涉及难以控制的相变和难以形貌控制，寻找具有高容量和良好循环稳定性的合适正极材料仍然是瓶颈问题。在此，通过简单且可扩展的自模板策略成功合成了P2型Na0.67Ni0.15Mn0.85O2阴极的独特的类富勒烯空心多面体，与块状对应物相比，可以大大增强电化学性能。在100 mA g−1倍率下循环120次后，它可以提供101 mAh g−1的高比容量，达到96.8 %的优异容量保持率。进一步分析了性能增强的可能根源是中空内部和多面体新颖形态的协同效应，导致良好暴露的（002）面、更短的扩散路径和更好的结构鲁棒性。重要的是，未经预钠化处理的全电池可以根据正极和负极的总质量提供133.1 Wh kg−1的高能量密度，这为设计高能量密度钠离子全电池提供了新的思路。
Sodium‐ion batteries are considered as the most promising candidates for grid‐level energy storage applications due to its unique features of much lower cost and comparable energy density to lithium ion batteries. However, searching for suitable cathode materials with high capacity and good cycling stability are still the bottleneck issues due to the involved unmanageable phase transitions and difficult morphology control. Herein, unique fullerene‐like hollow polyhedrons of P2‐type Na0.67Ni0.15Mn0.85O2cathode were successfully synthesized via a facile and scalable self‐template strategy, where largely enhanced electrochemical properties can be achieved compared to its bulk counterpart. It can deliver a high specific capacity of 101 mAh g−1after 120 cycles at a rate of 100 mA g−1, reaching an excellent capacity retention of 96.8 %. The possible origins of the enhanced performance were further analyzed to be the synergistic effect of hollow interior and novel morphology of the polyhedron, leading to well exposed (002) planes, shorter diffusion path and better structural robust. Importantly, the full battery without pre‐sodiation treatment could deliver a high energy density of 133.1 Wh kg−1based on the total mass of cathode and anode, which sheds a new light for designing high energy density sodium‐ion full batteries.