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

LiCoO 2 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 LiCoO 2 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 mA h g−1. This research provides novel insights into the design of electrolyte additives for high-voltage LiCoO 2 batteries and contributes to the further development of high-voltage lithium-ion batteries. • The addition of EMS expands the electrochemical window and improves the oxidation stability of electrolyte. • EMS can suppress the crystal structure change of LCO cathode. • EMS can the suppress the growth of lithium dendrites and reduce the side reactions under high voltage. • Both cathode/electrolyte and anode/electrolyte interfaces are studied. [ABSTRACT FROM AUTHOR]