Ethylene carbonate-free fluoroethylene carbonate-based electrolyte works better for freestanding Si-based composite paper anodes for Li-ion batteries

JOURNAL OF POWER SOURCES

卷:381

Article

Yao, K.^1,2,3  Zheng, J. P.^1,2,4,5  Liang, R.^1,3,6 

[1] Florida State Univ, Mat Sci & Engn, Tallahassee, FL 32306 USA

[2] Florida State Univ, Aeropropuls Mechatron & Energy Ctr AME, Tallahassee, FL 32306 USA

[3] Florida State Univ, High Performance Mat Inst HPMI, Tallahassee, FL 32306 USA

[4] Florida State Univ, CAPS, Tallahassee, FL 32306 USA

[5] Florida A&M Univ, Florida State Univ, Coll Engn, Dept Elect & Comp Engn, Tallahassee, FL 32310 USA

[6] Florida A&M Univ, Florida State Univ, Coll Engn, Dept Ind & Mfg Engn, Tallahassee, FL 32310 USA

关键词: Li-ion battery;    Si anode;    Ethylene carbonate-free;    Fluoroethylene carbonate electrolyte;   

DOI  :  10.1016/j.jpowsour.2018.02.013

来源: Elsevier

【 摘 要 】

Fluoroethylene carbonate (FEC)-based electrolytes using FEC as the co-solvent (50 wt%) are investigated and compared with the electrolyte using FEC as the additive (10 wt%) for freestanding Si-carbon nanotubes (CNTs) composite paper anodes for Li-ion batteries. The ethylene carbonate (EC)-free FEC-based electrolyte is found to achieve higher specific capacity and better capacity retention in terms of long-term cycling. After 500 cycles, the capacity retention of the cell using diethyl carbonate (DEC)-FEC (1:1 w/w) is increased by 88% and 60% compared to the cells using EC-DEC-FEC (45:45:10 w/w/w) and EC-FEC (1:1 w/w), respectively. Through SEM-EDX and XPS analyses, a possible reaction route of formation of fluorinated semicarbonates and polyolefins from FEC is proposed. The inferior cell performance related to the EC-containing electrolytes is likely due to the formation of more polyolefins, which do not favor Li ion migration.

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