Self-Assembled CoS Nanoflowers Wrapped in Reduced Graphene Oxides as the High-Performance Anode Materials for Sodium-Ion Batteries
Self-Assembled CoS Nanoflowers Wrapped in Reduced Graphene Oxides as the High-Performance Anode Materials for Sodium-Ion Batteries
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包裹还原氧化石墨烯的自组装 CoS 纳米花作为高性能钠离子电池负极材料
DOI：
10.1002/chem.201702399
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Wei YJ
中科院分区：
文献类型：
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作者：
Zhao Yingying;Pang Qiang;Meng Yuan;Gao Yu;Wang Chunzhong;Wei Yingjin;Du Fei;Chen Gang;Wang Chunzhong;Liu Bingbing;Du Fei;Chen Gang;Wang CZ;Wei YJ
寻找高性能负极材料以促进钠离子电池的实际应用仍然是一个巨大的挑战。在此，报道了包裹在还原氧化石墨烯（RGO）中的 CoS 纳米花的简便合成，并与裸 CoS 相比，系统地研究了它们的钠存储特性。 CoS@RGO纳米花在100 mA g−1的电流密度下具有620 mAh g−1的高可逆容量，并且在4 A g−1时具有329 mAh g−1的优越倍率性能，远高于裸CoS的放电容量。电化学阻抗谱和异位SEM图像证明，钠存储性能的改善是由于引入了RGO作为导电基质，不仅增加了CoS的动力学性质，而且在钠化（脱）过程中缓冲了体积变化并保持了工作电极的完整性。更重要的是，由于比面积和表面氧化还原行为增强，仅在 CoS@RGO 纳米复合材料中观察到超过 89% 的赝电容贡献。
It remains a big challenge to identify high‐performance anode materials to promote practical applications of sodium‐ion batteries. Herein, the facile synthesis of CoS nanoflowers wrapped in reduced graphene oxides (RGO) is reported, and their sodium storage properties are systematically studied in comparison with bare CoS. The CoS@RGO nanoflowers deliver a high reversible capacity of 620 mAh g−1at a current density of 100 mA g−1and superior rate capability with discharge capacity of 329 mAh g−1at 4 A g−1, much higher than those of the bare CoS. Evidenced by electrochemical impedance spectra and ex‐situ SEM images, the improvement in the sodium storage performance is found to be due to the introduction of RGO which serves as a conducting matrix, to not only increase the kinetic properties of CoS, but also buffer the volume change and maintain the integrity of working electrodes during (de)sodiation processes. More importantly, the pseudocapacitive contribution of more than 89 % is only observed in the CoS@RGO nanocomposites, owing to the enhanced specific area and surface redox behavior.