A review on the critical challenges and progress of SiOx-based anodes for lithium-ion batteries

With the advantages of abundant resources, high specific capacity, and relatively stable cycling performance, silicon suboxides (SiOx, x < 2) have been recently suggested as promising anodes for next-generation lithium-ion batteries (LIBs). SiOx exhibits superior storage capability because of the presence of silicon and smaller volume change upon charge/discharge than Si owing to the buffering effect of the initial lithiation products of inert lithium oxide and lithium silicates, enabling a stable cycle life of electrodes. However, significant improvements, such as overcoming issues related to volume changes in cycling and initial irreversible capacity loss and enhancing the ionic and electronic charge transport in poorly conducting SiOx electrodes, are still needed to achieve the satisfactory performance required for commercial applications. This review summarizes recent progress on the cycling performance and initial coulombic efficiency of SiOx. Advances in the design of particle morphology and composite composition, prelithiation and prereduction methods, and usage of electrolyte additives and optimized electrode binders are discussed. Perspectives on the promising research directions that might lead to further improvement of the electrochemical properties of SiOx-based anodes are noted. This paper can serve as a basis for the research and development of high-energy-density LIBs.