Interplay Between Composition and Cycling Performance of Pre-Lithiated SiOx-Si-C Composite Anodes for Lithium–Sulfur Full Cells
Swamickan Sathya, Ramasamy Santhosh Kumar, Sara García-Ballesteros, Federico Bella, Dong Jin Yoo, A. Manuel Stephan
Abstract
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 (SiOx)-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 SiOx/Si/C-based electrodes composed of different amorphous SiOx, Si, and graphitic carbon contents were prepared. Among the various investigated compositions, the electrode with a ratio of SiOx-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/SiOx-Si-C (pre-lithiated) configuration were assembled and their cycling performances are reported.