Minimizing catalyst amount in sulfur cathodes with titanium monoxide: Toward more applicable Li-sulfur batteries

Abstract

Using economical oxide catalysts into sulfur (S8) cathodes proves an efficient way to address kinetic issues in Li-sulfur batteries (LSBs). However, these catalysts often occupy too much proportion in weight, thus attenuating the cathode gravimetric energy density. Also, they tend to be sulfurized/ deteriorated in electrode fabrication or battery cycling. To overcome above constraints, we herein propose to minimize the catalyst amount in S8 cathodes with titanium monoxide (TiO) nanoclusters. In such configured cathodes, there are only ∼ 1.47 % of TiO nano catalysts in weight; such oxides with rich (200) facet prove efficient kinetic-boosting properties on Li2Sn phase conversions. Notably, they exhibit prominent electrochemical stability over all cyclic periods, without evident sulfuration or phase deteriorations. The in-situ Raman monitoring toward LSBs reveals the liquid-to-solid polysulfide transitions can be well accelerated even under lean-catalyst conditions. As evaluated, the cathodes of S8 infused in lean TiO-involved carbon hosts (S8@L-TiO@CH) show a great specific capacity of 1331 mAh g−1 at 0.2 C, with a high capacity retention ratio of 78.5 % at the end of cycling. This work may guide a research trend to endow S8 cathodes with elevated viability/durability for practical usage.