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.