Improved cycling performance of Si nanoparticle anodes via incorporation of methylene ethylene carbonate

•Effects of MEC on cycling ability of Si nanoparticle anodes was investigated.•MEC greatly improved capacity retention of Si anode compared to standard electrolyte.•High concentration of poly(MEC) was found in MEC-derived SEI.

Methylene ethylene carbonate (MEC) has been investigated as an alternative additive to fluoroethylene carbonate (FEC) for Si nanoparticle anodes cycled with 1.2 M LiPF6/ethylene carbonate (EC): diethyl carbonate (DEC) (1:1, w/w) electrolyte. The Si electrodes cycled with 10% MEC-added electrolyte exhibit significantly improved capacity retention after 100 cycles compared to standard electrolyte (73% vs 46%). In addition, the Si electrode cycled with MEC additive has less damage from cracking than the standard electrolyte. Ex situ surface analyses via infrared and X-ray photoelectron spectroscopy reveal a solid electrolyte interphase (SEI) containing a high concentration of a poly(MEC), which is likely responsible for the improved performance of Si anodes.

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