Stabilizing electrode/electrolyte interface in Li-S batteries using liquid/solid Li2S-P2S5 hybrid electrolyte

Lithium-sulfur (Li-S) batteries using hybrid electrolytes, which are composed of solid-electrolyte separator and liquid-electrolyte wetting agent, can effectively eliminate the polysulfide shuttling issue. The cycling performance of these hybrid batteries is mainly limited by the interfacial stability between the solid and liquid electrolytes. This work detailly discusses the influence of the composition on the stability of a highly ionic conductive sulfide solid electrolyte, lithium thiophosphate xLi(2)S center dot(100-x)P2S5 (70 <= x <= 75, SSEs), in hybrid Li-S batteries. It reveals that the solid electrolyte with low Li2S content favors the formation of a SEI layer containing Li3PS4 and therefore improves the interfacial stability with Li anode, while the one with high Li2S content behaves more stable with the cathode. Using 75Li(2)S center dot 25P(2)S(5) as the separator, a hybrid battery runs more than 400 cycles with a low capacity fading rate of 0.14%/cycle. This is benefited from the elimination of polysulfide shutting and especially the excellent compatibility of the sulfide solid electrolyte with both anode and cathode.

Automated summary

The use of hybrid electrolytes in lithium-sulfur batteries can effectively address polysulfide shuttling issue. The stability of highly ionic conductive sulfide solid electrolyte in hybrid Li-S batteries is influenced by its composition. By optimizing the solid electrolyte content, the interfacial stability with both anode and cathode can be improved, leading to enhanced cycling performance of the battery.