Vinylene carbonate and tris(trimethylsilyl) phosphite hybrid additives to improve the electrochemical performance of spinel lithium manganese oxide/graphite cells at 60 °C

• The combination of tris(trimethylsilyl) phosphite and vinylene carbonate improves the electrochemical performance of lithium manganese oxide/graphite cells at 60 °C.
• Removal of hydrogen fluoride and water by tris(trimethylsilyl) phosphite suppresses manganese dissolution from lithium manganese oxide.

The organophosphorus compounds tris(trimethylsilyl) phosphite (TMSP) and vinylene carbonate (VC) have been considered for use as functional additives to improve the electrochemical performance of Li1.1Mn1.86Mg0.04O4 (LMO)/graphite full cells. Our investigation reveals that the combination of VC and TMSP as additives enhances the cycling properties and storage performance of full cells at 60 °C. The unique functions of the TMSP additive in the VC electrolyte are investigated via ex situ X-ray photoelectron spectroscopy (XPS) and 19F nuclear magnetic resonance (NMR) measurements. The TMSP additive effectively eliminates trace water and hydrogen fluoride (HF) and produces a protective film on the LMO cathode that alleviates manganese dissolution at 60 °C.