Fabrication and electrochemical behavior of a lithium-sulfur cell with a TiO2-sulfur-carbon aerogel-based cathode

摘要

The electrochemical properties of a TiO2-sulfur-carbon aerogel cathode, which was based on a sulfur-carbon aerogel (S-CA) composite and amorphous TiO2, were investigated. The results of cyclic voltammetry measurements indicated that the TiO2-S-CA cathode was highly stable. Further, the results of galvanostatic charge/discharge measurements demonstrated that the capacity retention of a Li-S cell based on this cathode at the end of 100 cycles was 71 % of the initial capacity; in contrast, that of cell based on a S-CA cathode was only 43.9 %. On the basis of these result, various factors for improving the cycling life of cells based on this TiO2-S-CA cathode are discussed. Furthermore, the cell with the TiO2-S-CA cathode exhibited robustness and a high degree of reversibility at different discharge rates. Finally, electrochemical impedance spectroscopy was performed at different discharge states in order to study the effects of the microstructure of the composite cathode on its electrochemical performance.