A novel multifunctional additive strategy improves the cycling stability and thermal stability of SiO/C anode Li-ion batteries

SiO/C anode materials for high-energy-density lithium-ion batteries (LIBs) have attracted considerable attention. However, battery capacity degradation and thermal safety problems caused by the large volume variation in the SiO/C anode during the long cycle limit its application. We propose the use of two composite additives to overcome the limitations of the current SiO/C anode materials. The electrochemical performance and thermal stability of the blank electrolyte (BE) and two composite additives were systematically compared using electrochemical, characterisation, and thermokinetic methods. The results revealed the synergistic effect of (2-cyanoethyl) triethoxysilane (TEOSCN) and 4, 5–difluoro‑1, 3–dioxolan‑2–one (DFEC) improved the cycling and thermal stability of the cells. The use of the additives resulted in the formation of a dense and thin SEI layer with LiF as the main material on the surface of the anode, which significantly improved the cycling stability of Li/SiO@C batteries. In addition, differential scanning calorimetry (DSC) measurements and thermokinetic analysis indicated that the addition of TEOSCN/DFEC significantly enhanced the thermal stability of the cells, which was mainly manifested as the delay of the exothermic peak and the increase in the activation energy of the mixture of the SiO/C anode and electrolyte. Our results suggested that the multifunctional additive offers a viable approach for developing LiBs with high energy density and excellent safety.