Potassium Ions Regulated the Disproportionation of Silicon Monoxide Boosting Its Performance for Lithium-Ion Battery Anodes

Silicon monoxide (SiO) has captured great attention as one of the most promising anode materials due to its great cycling stability as well as high theoretical capacity. However, hindered by its low initial Coulombic efficiency, the possible large-scale application remains an urgent issue. Herein, through a facile method, potassium ions are introduced into the disproportionation process of SiO to promote the transition from amorphous SiOx into the cristobalite phase with higher crystallinity. The cristobalite phase exhibits lower reaction activity with lithium ions, which reduces the formation of lithium silicate. As a consequence, the cycling stability and the initial Coulombic efficiency (ICE) are improved. In addition, it is proved in our study that increasing the heating temperature is helpful to improve the ICE and cycling stability of SiO. This work provides a facile disproportionation method for the microstructure regulation of SiO, offering a possible avenue for the development of large-scale applications of the SiO anode.