Constructing stable electrode–electrolyte interfaces by sulfone-based additive to improve the high-voltage performance of LiCoO2

LiCoO2 battery can provide high reversible capacity at a high voltage of 4.6 V, however, maintaining its stability at high voltages remains a major challenge. To address this issue, ethyl methyl sulfone (EMS) is employed as an electrolyte additive to construct stable interfaces between the electrode and electrolyte under high-voltage condition. The characterization results indicate that the addition of EMS can inhibit the decomposition of the standard electrolyte (STD) and the dissolution of Co2+ from cathode, as well as the formation of lithium dendrites on the Li anode, thereby enhancing the stability of both cathode/electrolyte and anode/electrolyte interfaces. Consequently, the cycling performance of LiCoO2 battery using STD+3%EMS is augmented by 16.9% at 1 C under a cut-off voltage of 4.6 V over 100 cycles, delivering a specific capacity of 137 mAh g-1. This research provides novel insights into the design of electrolyte additives for high-voltage LiCoO2 batteries and contributes to the further development of high-voltage lithium-ion batteries.