期刊
ENERGY STORAGE MATERIALS
卷 23, 期 -, 页码 749-756出版社
ELSEVIER
DOI: 10.1016/j.ensm.2019.04.004
关键词
Magnesium ion battery; VS2 nanosheets; Electrolyte additive; Catalytic effect; Electrochemical performance
资金
- Ministry of Science and Technology of China [2015CB251103]
- National Natural Science Foundation of China [51472104, 21473075, 21773091]
- Science and Technology Department of Jilin Province [20180414004GH]
The difficult Mg2+ desolvation of chloride-based electrolytes and slow Mg2+ diffusion in the cathode seriously hinder the electrochemical performance of Mg-ion batteries (MIBs). To solve these problems, a high performance MIB cell was built using a VS2 nanosheet cathode and with 0.4 M (PhMgCl)(2)-AlCl3/tetrahydrofuran (APC/THF) and 50 wt.% 1-butyl-1-methylpiperidinium chloride (PP14Cl) as the electrolyte. The resulting system showed a large capacity of 348 mA h g(-1) at 20 mA.g(-1) current density and excellent rate capability with a 214 mA h g(-1) capacity at 2.0 A.g(-1) current density. A thorough experimental and theoretical study showed that Mg2+ desolvation energy was reduced from 3.0 to 0.67 eV under the catalytic effects of PP14+. Moreover, large-sized PP14+ was inserted into the VS2 interlayer during the first discharge and permanently resided in the material. As a result, the interlayer spacing of VS2 was largely expanded, which improved the Mg2+ diffusion coefficient by three orders of magnitude to 10(-10)-10(-12) cm(-2)s. The reduced Mg2+ desolvation energy by the catalytic effects of PP14+, together the improved Mg2+ diffusion kinetics by the interlayer expansion effect of PP14+, provided a significant implement way towards development of high performance and practical MIBs by electrolyte regulation.
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