Nitrogen-doped Carbon Coated Na3V2(PO4)3 with Superior Sodium Storage Capability
Nitrogen-doped Carbon Coated Na3V2(PO4)3 with Superior Sodium Storage Capability
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DOI：
10.1007/s40242-020-9088-3
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发表时间：
2020-01
影响因子：
3.1
通讯作者：
Laiqiang Xu;Jiayang Li;Yitong Li;Peng Cai;Cheng Liu;Guoqiang Zou;Hongshuai Hou;Lan Huang;Xiaobo Ji
中科院分区：
文献类型：
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作者：
Laiqiang Xu;Jiayang Li;Yitong Li;Peng Cai;Cheng Liu;Guoqiang Zou;Hongshuai Hou;Lan Huang;Xiaobo Ji
可再生能源存储应用中的常温钠离子电池需要具有高循环稳定性和倍率能力的正极。 Na3V2(PO4)3 是一种有吸引力的阴极材料，在 3D NASICON 结构内具有出色的电化学稳定性和快速离子扩散系数。然而，Na3V2(PO4)3本身较差的电子导电性严重阻碍了其实际应用。本文提出了溶剂蒸发法来获得氮掺杂碳包覆的Na3V2(PO4)3正极材料，从而增强了电化学性能。 N掺杂碳层涂层充当高导电通路，并产生大量外在缺陷和活性位点，这可以促进Na+的存储和扩散。此外，N掺杂碳层可以提供稳定的框架以适应电极循环时电极的团聚。氮掺杂碳涂层的 Na3V2(PO4)3(NC-NVP) 比无碳涂层的裸 Na3V2(PO4)3 表现出优异的长循环寿命和优异的倍率性能。 NC-NVP在1 C倍率下循环500次后可提供95.9 mA·h/g的稳定容量，这相当于相对于初始容量（101.4 mA·h/g）的高容量保持率（94.6%）。 5 C倍率下循环500次后仍保留91.3%以上的初始容量，30 C倍率下容量可达85 mA·h/g。
Cathodes with high cycling stability and rate capability are required for ambient temperature sodium ion batteries in renewable energy storage application. Na3V2(PO4)3is an attractive cathode material with excellent electrochemical stability and fast ion diffusion coefficient within the 3D NASICON structure. Nevertheless, the practical application of Na3V2(PO4)3is seriously hindered by its intrinsically poor electronic conductivity. Herein, solvent evaporation method is presented to obtain the nitrogen-doped carbon coated Na3V2(PO4)3cathode material, delivering enhanced electrochemical performances. N-Doped carbon layer coating serves as a highly conducting pathway, and creates numerous extrinsic defects and active sites, which can facilitate the storage and diffusion of Na+. Moreover, theN-doped carbon layer can provide a stable framework to accommodate the agglomeration of the electrode upon electrode cycling. N-Doped carbon coated Na3V2(PO4)3(NC-NVP) exhibits excellent long cycling life and superior rate performances than bare Na3V2(PO4)3without carbon coating. NC-NVP delivers a stable capacity of 95.9 mA·h/g after 500 cycles at 1 C rate, which corresponds to high capacity retention(94.6%) with respect to the initial capacity(101.4 mA·h/g). Over 91.3% of the initial capacity is retained after 500 cycles at 5 C, and the capacity can reach 85 mA·h/g at 30 C rate.