Stable Lithium Sulfur Battery Based on In Situ Electrocatalytically Formed Li₂S on Metallic MoS₂–Carbon Cloth Support

Abstract

Abstract A stable lean‐electrolyte operating lithium–sulfur (Li–S) battery based on a cathode of Li 2 S in situ electrocatalytically deposited from L 2 S 8 catholyte onto a support of metallic molybdenum disulfide (1T‐MoS 2 ) on carbon cloth (CC) is created. The 1T‐MoS 2 significantly accelerates the conversion Li 2 S 8 catholyte to Li 2 S, chemically adsorbs lithium polysulfide (LiPSs) from solution, and suppresses crossover of the LiPSs to the anode. These experimental findings are explained by density functional theory calculations that show that 1T‐MoS 2 gives rise to strong adsorption of polysulfides on its surface and is electrocatalytic for the targeted reversible Li–S conversion reactions. The CC/1T‐MoS 2 electrode in a Li–S battery delivers an initial capacity of 1238 mAh g −1 , with a low capacity fade of only 0.051% per cycle over 500 cycles at 0.5 C . Even at a high sulfur loading (4.4 mg cm −2 ) and low electrolyte/S (E/S) ratio of 3.7 µL mg −1 , the battery achieves an initial reversible capacity of 1176 mA h g −1 at 0.5 C , with 87% capacity retention after 160 cycles. The post 500 cycles Li metal opposing 1T‐MoS 2 is substantially smoother than the Li opposing CC, with XPS supporting the role of 1T‐MoS 2 in inhibiting LiPSs crossover.