Enhanced rate capability due to highly active Ta2O5 catalysts for lithium sulfur batteries

Abstract

The heterogeneous catalysis is widely recognized to promote polysulfide fragmentations can play a key role for the rate capability enhancement of lithium sulfur batteries (LSB). In this study, we report the most active catalysts (Ta2O5) for LSB which showed an enhanced rate capability (914 mAh g(-1) at 5 C) in comparison with the previously reported catalysts, TiN (865 mAh g(-1) at 5 C). The addition of Ta2O5 into the carbon-coated separator facilitates the chemical disproportionation of reaction intermeditates, Li2S4 into Li2S8 and Li2S effectively, which leads to the greatly lengthened second plateau in discharge profile. The heterogeneous catalysis of Ta2O5 is clearly verified with the UV-Vis spectra directly showing the change of Li2S4 concentration and the battery performance tests without any active elemental sulfur.