A P2-Na0.67Co0.5Mn0.5O2 cathode material with excellent rate capability and cycling stability for sodium ion batteries
A P2-Na0.67Co0.5Mn0.5O2 cathode material with excellent rate capability and cycling stability for sodium ion batteries
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DOI：
10.1039/c6ta02845d
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发表时间：
2016-07
影响因子：
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通讯作者：
Yuan-En Zhu;Xingguo Qi;Xiaoqing Chen;Xianlong Zhou;Xu Zhang;Jinping Wei;Yong‐Sheng Hu;Zhen Zhou-Zhen-Zh
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文献类型：
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作者：
Yuan-En Zhu;Xingguo Qi;Xiaoqing Chen;Xianlong Zhou;Xu Zhang;Jinping Wei;Yong‐Sheng Hu;Zhen Zhou-Zhen-Zh
钠离子电池被认为是下一代能量存储设备;然而，稳定的阴极材料对于钠离子电池是非常期望的和具有挑战性的。在此，我们报告的制备层状正极材料，P2-Na0.67Co0.5Mn0.5O2，具有分级结构，通过一个方便和简单的溶胶-凝胶路线。X射线衍射（XRD）和高分辨率透射电子显微镜阐明了一个定义明确的P2型相结构，并在原位XRD测量提供了进一步的证据，在脱钠/钠化的结构稳定性。得益于结构稳定性，该阴极材料在0.1C倍率下提供了147 mA h g−1的高放电容量，以及在1C下至少100次循环后具有接近100%容量保持率的优异循环稳定性。更重要的是，当电极在30 C的极高速率下循环时，保持88 mA h g−1，并且在2000次循环中几乎保留了其容量的一半，这优于所有已报道的P2型阴极材料。P2-Na0.67Co0.5Mn0.5O2正极材料具有优异的电化学性能和结构灵活性，将促进钠离子电池的实际应用。
Sodium ion batteries are considered as next-generation energy storage devices; however, stable cathode materials are highly desirable and challenging for sodium ion batteries. Herein, we report the preparation of a layered cathode material, P2-Na0.67Co0.5Mn0.5O2, with a hierarchical architecture, through a facile and simple sol–gel route. X-ray diffraction (XRD) and high resolution transmission electron microscopy elucidated a well-defined P2-type phase structure, and in situ XRD measurements provided further evidence about the structural stability during desodiation/sodiation. Benefiting from the structural stability, the cathode material delivered a high discharge capacity of 147 mA h g−1 at 0.1C rate, and excellent cyclic stability with nearly 100% capacity retention over at least 100 cycles at 1C. More importantly, 88 mA h g−1 was maintained when the electrode was cycled at a very high rate of 30C, and almost half of its capacity was retained over 2000 cycles, which outperforms all the reported P2-type cathode materials. With outstanding electrochemical performance and structural flexibility, the P2-Na0.67Co0.5Mn0.5O2 cathode material will promote the practical applications of sodium ion batteries.