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Self‐Assembled CoS Nanoflowers Wrapped in Reduced Graphene Oxides as the High‐Performance Anode Materials for Sodium‐Ion Batteries
Author(s) -
Zhao Yingying,
Pang Qiang,
Meng Yuan,
Gao Yu,
Wang Chunzhong,
Liu Bingbing,
Wei Yingjin,
Du Fei,
Chen Gang
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201702399
Subject(s) - graphene , anode , materials science , electrochemistry , nanocomposite , chemical engineering , sodium , redox , electrode , nanotechnology , current density , chemistry , metallurgy , physics , quantum mechanics , engineering
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 −1 at a current density of 100 mA g −1 and superior rate capability with discharge capacity of 329 mAh g −1 at 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.