Electrode Surface Film Formation in Tris(ethylene glycol)-Substituted Trimethylsilane-Lithium Bis(oxalate)borate Electrolyte

One of the silicon-based electrolytes, tris(ethylene glycol)-substituted trimethylsilane (1NM3)-lithium bis(oxalate)borate (LiBOB), is studied as an electrolyte for the LiMn2O4 cathode and graphite anode cell. The solid electrolyte interface (SEI) characteristics and chemical components of both electrodes were investigated by X-ray photoelectron spectroscopy and X-ray diffraction. It was found that SET components on the anode are similar to those using carbonate-LiBOB electrolyte, which consists of lithium oxalate, lithium borooxalate, and LixBOy. Moreover, we demonstrated that 1NM3-LiPF6 electrolyte, which lacks an SEI formation function, could not maintain the graphite structure during the electrochemical process. Therefore, it is evident that the 1NM3 LiBOB combination and its suitable SET film formation capability are vital to the lithium ion battery with graphite as the anode.