Vanadium doped in-plane 1T-2H molybdenum disulfide heterostructure as efficient electrocatalyst for lithium-sulfur batteries

The active electronic states in 1T-MoS₂ are highly desirable for catalyzing polysulfides conversion. However, stable 1T-MoS₂ is difficult to produce using common approaches. Herein, V uniformly doped in-plane 1T-2H heterostructured MoS₂ nanosheets (V-MoS₂) are prepared by a facile hydrothermal method with a polyoxometalate precursor containing periodic Mo and V atomic arrangement. The doping of V induces the phase transition from semiconducting 2H-MoS₂ to metallic 1T-MoS₂ and stabilizes the resulted 1T phase. Importantly, the incorporation of V not only modifies the surface electronic property of MoS₂, enhancing the active site density, but also improves the adsorption of polysulfides and the catalytic efficiency for sulfur redox reactions. With these advantages, the Li-S batteries using V-MoS₂ electrocatalyst achieve accelerated reaction kinetics and superior electrochemical performance. When the S loading of the cathode is 5.41 mg cm⁻², a favorable discharge capacity of 4.98 mAh cm⁻² is obtained with satisfying cycle stability. This work provides an efficient atomic engineering approach for the design of high performance electrocatalyst for Li-S batteries.