Interplay Between Composition and Cycling Performance of Pre-Lithiated SiO_x-Si-C Composite Anodes for Lithium–Sulfur Full Cells

Although silicon-based anodes have been identified as a potential alternative to conventional graphite anodes, the huge volume change (approximately 300%) that occurs in silicon while cycling still impedes this system from practical applications. In the case of silicon-suboxide (SiO_x)-based anode materials, both Li₂O and LiSiO₄ are formed during the initial lithiation processes and act as a natural volume buffer matrix to accommodate volume changes and the formation of a stable SEI layer, which improves the cyclability and capacity retention. In this study, a series of SiO_x/Si/C-based electrodes composed of different amorphous SiO_x, Si, and graphitic carbon contents were prepared. Among the various investigated compositions, the electrode with a ratio of SiO_x-Si-C equal to 70:12.5:12.5 was found to be optimal in terms of discharge capacity. This promising electrode was pre-lithiated prior to cycling. Finally, 2032-type lithium–sulfur (Li-S) coin cells composed of a S-C/SiO_x-Si-C (pre-lithiated) configuration were assembled and their cycling performances are reported.