Improving lithium polysulfides adsorption by oxygen-vacancy defects: By first-principles calculation

The serial interaction of lithium polysulfides (LiPSs) intermediates that possibly occurred on the surface of vacancy-defective manganese oxides have been investigated by First-principles calculation. Vacancy defects will cause the adjustment of micro regional electron density and produce stronger polarization for polar materials MnO2. The investigation of the stable adsorption site of LiPSs on defective MnO2 surface shows that oxygen -vacancy traps are beneficial for capturing LiPSs. Due to the existence of unpaired electrons, the interaction between vacancy-defective manganese oxide and Li2Sn molecules become stronger than pristine manganese oxide, which are propitious to decrease the adsorption energy for Li2Sn (n = 1, 2, 4, 6, 8) molecules. That is to say, vacancy defects can supply an effective nucleation sites that effectively enhance the affinity for Li2S and catalyze the conversion of LiPSs, which improve the shuttle effect and increase the utilization of active materials.