Construction of strong built-in electric field in binary metal sulfide heterojunction to propel high-loading lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries is greatly hindered by soluble polysulfides shuttling and sluggish sulfur redox kinetics. Rational design of multifunctional hybrid materials with superior electronic conductivity and high electrocatalytic activity, e.g., heterostructures, is a promising strategy to solve the above obstacles. Herein, a binary metal sulfide MnS-MoS2 heterojunction electrocatalyst is first designed for the construction of high-sulfur-loaded and durable Li-S batteries. The MnS-MoS2 p-n heterojunction shows a unique structure of MoS2 nanosheets decorated with ample MnS nanodots, which contributes to the formation of a strong built-in electric field at the two-phase interface. The MnS-MoS2 hybrid host shows strong soluble polysulfide affinity, enhanced electronic conductivity, and exceptional catalytic effect on sulfur reduction. Benefiting from the synergistic effect, the as-derived S/ MnS-MoS2 cathode delivers a superb rate capability (643 mA h g(-1) at 6 C) and a durable cyclability (0.048% decay per cycle over 1000 cycles). More impressively, an areal capacity of 9.9 mA h cm(-2) can be achieved even under an extremely high sulfur loading of 14.7 mg cm(-2) and a low electrolyte to sulfur ratio of 2.9 mu L mg(-1). This work provides an in-depth understanding of the interfacial catalytic effect of binary metal compound heterojunctions on sulfur reaction kinetics. (c) 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.