Catalytic hosts with strong adsorption strength for long shelf-life lithium-sulfur batteries under lean electrolyte

Low electrolyte/sulfur ratio(E/S)is an important factor in increasing the energy density of lithium-sulfur batteries(LSBs).Recently,the E/S has been widely lowered using catalytic hosts that can suppress“shuttle effect”during cycling by relying on a limited adsorption area.However,the shelf-lives of these cathodes have not yet received attention.Herein,we show that the selfdischarge of sulfur cathodes based on frequently-used catalytic hosts is serious under low E/S because the“shuttle effect”during storage process caused by polysulfides(PSs)disproportionation cannot be suppressed using a limited adsorption area.We further prove that the adsorption strength toward PSs,which is unfortunately weak in commonly-used catalytic hosts,is critical for effectively hindering the disproportionation of the PSs.Subsequently,to verify this conclusion,we prepare a sulfur-doped titanium nitride(S-TiN)catalytic array host.As the adsorption strength and catalytic activity of TiN can be improved by S doping simultaneously,the constructed S/S-TiN cathodes under a low E/S(6.5μL·mg−1)exhibit better shelf-life and cycle-stability than those of S/TiN cathodes.Our work suggests that enhancing the adsorption strength of catalytic hosts,while maintaining their function to reduce E/S,is crucial for practical LSBs.