Rational nanostructured FeSe2 wrapped in nitrogen-doped carbon shell for high-rate capability and long cycling sodium-ion storage
2022
Ma, Qiuyang | Zhang, Liang | Ding, Yang | Shi, Xiang | Ding, Yong liang | Mujtaba, J. | Li, Zhongyuan | Fang, Zhen
Transition metal selenides (TMSs) have drawn substantial attention as promising anode materials for sodium-ion batteries (SIBs) on account oftheir rapid reaction kinetics and high reversible capacity. However, the undesirable capacity decay and inferior rate performance still hamper their large-scale application. Herein, an anode material comprising combination of olivary nanostructure FeSe₂ core and nitrogen-doped carbon shell (designated as FeSe₂@NC) is well designed by in-situ polymerization and selenization method. The well-designed nitrogen-doped carbon shell can not only alleviate the volume variation during the electrode cycling but also provide an optimized ion/electron transport pathway. The resulting FeSe₂@NC electrodes exhibit a superior rate capability of 228.4 mA h g⁻¹ at 10 A g⁻¹ and a long cycling performance of 246.5 mA h g⁻¹ at 5 A g⁻¹ after 1000 cycles, which can be assigned to the enhanced structural integrity and improved electrical conductivity. The strategy would present a promising thought for structure design of TMSs as anode materials, which could enhance high-rate and long-lasting cycle performances for SIBs.
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