Cocklebur-like ZnSe-VO2@rGO nanostructures as host to boost the performance of lithium-sulfur batteries

Although lithium sulfur batteries (LSBs) have high theoretical capacity and energy density, low conductivity of sulfur and the discharge species (Li2S2, Li2S), the polysulfide shuttle and the large volume change hinder the commercialization of LSBs. To tackle the problem, we hydrothermally prepared a special cocklebur-like ZnSe-VO2@rGO nanostructure, in which graphene oxide (GO) is active in inducing thorn-like VO2 nanorods grown on carambola-like VO2 nanostructures. In this structure, the polar VO2 and ZnSe quantum dots (QDs) have strong chemical adsorption that can catalyze the polysulfide conversion and alleviate the shuttle ef-fect; besides, the thorn-like VO2 nanorods act like numerous tentacles that capture polysulfides by in-creasing the contact area, and the reduced graphene oxide (rGO) nanosheets not only buffer the volume change, but also enhance the conductivity of the framework and improve the ion and electron transfer. Boosted by the synergetic effects of VO2, rGO and ZnSe QDs, the ZnSe-VO2@rGO/S cathode achieves a high specific capacity of 1026.1 mA h g-1 at 0.2 C and 712.3 mA h g-1 at 2 C. Good cyclic stability was obtained as well, with a high reversible capacity of 820 mA h g-1 and high retention of 89.1 % after cycling at 0.5 C for 150 cycles. Such outstanding performance indicated its good potential for use in advanced LSBs.(c) 2022 Elsevier B.V. All rights reserved.