期刊
ENERGY STORAGE MATERIALS
卷 11, 期 -, 页码 1-7出版社
ELSEVIER
DOI: 10.1016/j.ensm.2017.09.002
关键词
Sodium-ion battery; Anode; VS2; Flower-like nanosheets; High rate-capability
资金
- 973 project [2015CB251103]
- National Nature Science Foundation of China [51472104, 51572107]
- Graduate Innovation Fund of Jilin University [2017114]
- Thousand Talents Program (China) [WQ20152200273]
Hierarchical flower-like VS2 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 NaCF3SO3 in diglyme), flower-like VS2 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 VS2 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, VS2 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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