Electrochemical Performance of Si/Graphite/Carbon Composite Electrode in Mixed Electrolytes Containing LiBOB and LiPF6

Abstract

The influences of lithium bis(oxalato) borate (LiBOB), vinylene carbonate (VC)-containing , and the mixed electrolytes with their different ratios on the electrochemical properties of Si/graphite/disordered carbon (Si/G/DC) composite electrode were investigated. Si/G/DC in mixed electrolytes presented better cyclability than in with VC and a higher specific capacity than in LiBOB. Si/G/DC in electrolytes exhibited a high reversible capacity of and a high and stable coulombic efficiency after the first cycle when cycled at a rate of . Even after , the reversible capacity was still as high as , with a capacity fading of less than 0.08% per cycle. The analysis of scanning electron microscopy, electrochemical impedance spectra, and X-ray photoelectron spectroscopy indicated that the improvement of Si/G/DC composite electrode in cyclability resulted from the formation of impact and stable solid electrolyte interphase layers.