TiO2 embedded hydrothermally synthesized carbon composite as interlayer for lithium-sulfur batteries

Abstract

Lithium-sulfur battery chemistry is one of the best alternatives to meet the demand of future electric vehicles providing high theoretical capacity and energy density. However, Li-S batteries suffer from internal issues, most of which is due to the shuttle effect that mitigates their commercial availability. In this work, TiO2/carbon composite is synthesized by hydrothermal carbonization and used as interlayer to alleviate the shuttle effect. This interlayer is used without further pyrolysis in order not to lose the benefit of the functional groups of carbonaceous material which help in adsorbing polysulfides. Moreover, TiO2 chemically binds polysulfides and boosts the adsorbing ability of the interlayer on polysulfides to a large extent. In consequence of this approach, 630 mAh/g discharge capacity is obtained after 100 cycles at C/5 current density. The adsorption ability of the interlayer ending up with enhanced electrochemical performance is proven by XPS with the significant shifts in binding energies.