Effect of SiOx composition on the durability of anodes for next-generation Li-ion batteries

Lithium-ion batteries require components with higher energy density and longer cycle life. SiOx is a promising alternative for high capacity anode materials. However, it suffers from low conductivity and low initial Coulombic efficiency. Considering the high Coulombic of graphite material, some studies found that SiOx/graphite can effectively improve the electrochemical performance of the whole anode. However, SiOx would expand in lithium insertion process, leading to pulverization of the active material, resulting in rapid capacity fade. SiOx volume expansion in SiOx/graphite anodes can be controlled by adjusting the oxygen content on SiOx, and the effect of SiOx expansion can be successfully followed by investigating induced changes on the graphite structure. This is crucial to quantify the effect of stoichiometry of SiOx oxides on the stability of the anode from early stages and to design functional anodes that can preserve the mechanical properties after prolonged cycling.