4,5-Difluoro-1,3-dioxolan-2-one as a film-forming additive improves the cycling and thermal stability of SiO/C anode Li-ion batteries

SiO/C is currently considered the most favorable anode material for high-energy-density lithium-ion batteries (LIBs). Nevertheless, its potential applications are constrained because of its inherent capacity decay and thermal safety concerns engendered by its volumetric expansion during extended cycling periods. The present study investigated the effectiveness of 4,5-difluoro-1,3-dioxolane-2-one (DFEC) as a film-forming additive to augment the safety and electrochemical efficacy of LIBs. A blank electrolyte (BE) was used as a control. Electrochemical test and characterization results revealed that the capacity retention rate of a battery containing the DFEC additive improved significantly; specifically, it increased from 45.23% (for a battery with the BE) to 73.14%. DFEC also increased the quantity of LiF components on the anode surface, resulting in the formation of a robust and stable solid electrolyte interphase film, which enhanced the battery's cycling stability. Differential scanning calorimetry, thermogravimetric analysis, and thermokinetic analysis revealed that DFEC inhibited exothermic reactions between the electrolyte and the lithiated anode. Notably, the initial reaction temperature for the electrolyte slowly transitioned from 232.17 to 238.67 °C. The apparent activation energy increased from 439.56 to 506.995 kJ/mol. This study presents a practical approach for the development of safe, high-energy-density batteries by incorporating DFEC as a film-forming additive.