Zhang Yue, Wang Hang, Tang Yakun, Huang Yudai, Jia Dianzeng
State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University Urumqi 830017 Xinjiang PR China
RSC Adv. 2023 Jan 31;13(7):4168-4172. doi: 10.1039/d2ra05524d.
As one of the most promising cathodes for rechargeable sodium-ion batteries (SIBs), Layered transition metal oxides with high energy density show poor cycling stability. Judicious design/construction of electrode materials plays a very important role in cycling performance. Herein, a P2-NaMnO cathode material with hierarchical book-like morphology combining exposed (100) active crystal facets is synthesized by hydrothermal method. Owing to the superiority of the unique hierarchical structure, the electrode delivers a high reversible capacity of 163 mA h g at 0.2C and remarkable high-rate cyclability (88.8% capacity retention after 300 cycles at 10C). Its unique oriented stacking nanosheet constructed hierarchical book-like structure is the origin of the high electrochemical performance, which is able to shorten the diffusion distances of Na and electrons, and a certain gap between the nanosheets can also relieve the stress and strain of volume generated during the cycle. In addition, the exposed (100) active crystal facets can provide more channels for the efficient transfer of Na. Our strategy reported here opens a door to the development of high-stable oxide cathodes for high energy density SIBs.
作为最具潜力的可充电钠离子电池（SIBs）正极材料之一，具有高能量密度的层状过渡金属氧化物循环稳定性较差。电极材料的合理设计/构建对循环性能起着非常重要的作用。在此，通过水热法合成了一种具有分级书本状形态且结合暴露（100）活性晶面的P2-NaMnO正极材料。由于独特分级结构的优势，该电极在0.2C时具有163 mA h g的高可逆容量以及显著的高倍率循环性能（在10C下300次循环后容量保持率为88.8%）。其独特的取向堆叠纳米片构建的分级书本状结构是高电化学性能的来源，这能够缩短Na和电子的扩散距离，并且纳米片之间的一定间隙还可以缓解循环过程中产生的体积应力和应变。此外，暴露的（100）活性晶面可为Na的高效传输提供更多通道。我们在此报道的策略为开发用于高能量密度SIBs的高稳定性氧化物正极打开了一扇门。
