材料科学
法拉第效率
阳极
假电容
插层(化学)
电解质
离子
钠
钠离子电池
化学工程
电化学
高分辨率透射电子显微镜
电池(电)
纳米技术
冶金
热力学
电极
物理化学
有机化学
工程类
物理
功率(物理)
化学
作者
Dongxu Yu,Qiang Pang,Yu Gao,Yingjin Wei,Chunzhong Wang,Gang Chen,Fei Du
标识
DOI:10.1016/j.ensm.2017.09.002
摘要
Abstract Hierarchical flower-like VS 2 nanosheets assemblies are successfully synthesized via a facile solvothermal method, and their Na + storage behavior is systematically studied with respect to the galvanostatic charge-discharge profiles, cyclic voltammograms, rate capability and long-term cycle stability. With a well-controlled cut-off voltage (3.0–0.3 V) and suitable electrolyte (1.0 M NaCF 3 SO 3 in diglyme), flower-like VS 2 delivers a high reversible capacity of around 600 mAh g −1 at 0.1 A g −1 and excellent cycle stability with 83% and 87% of its initial capacities retained after 700 cycles at 2 and 5 A g −1 , respectively. Remarkably, the VS 2 anode shows a high initial Coulombic efficiency of 94% and nearly 100% in the subsequent cycles, which points to the promising application of the present material in the commercial sodium-ion batteries. Moreover, VS 2 nanostructures also exhibit superior rate performance with a discharge capacity of 277 mAh g −1 at a current density of as high as 20 A g −1 . Quantitative kinetic analysis indicates that the sodium storage is governed by a pseudocapacitance mechanism, particularly at high current rates. Combined with ex-situ Raman, HRTEM and SAED characterizations further reveal that the Na + storage is based on electrochemical intercalation-de-intercalation reactions.
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