Abstract: Lithium sulfur batteries are considered one of the most promising electrochemical energy storage devices for the next generation due to their theoretical specific capacity of 1675 mAh/g and energy density of 2600 Wh/kg. However, the slow kinetics of the oxidation-reduction reaction of sulfur and lithium sulfide in lithium sulfur batteries, the shuttle effect of polysulfides, and the growth of lithium dendrites seriously hinder the development and application of lithium sulfur batteries. Therefore, a flexible Nb3VSe6/carbon nanofiber composite membrane (NVSCNF) was prepared and used as an electrocatalytic membrane reactor for lithium sulfur batteries (NVS@MR). A layered catalyst with embedded induction was constructed by modifying 2H-NbSe2 through V atom intercalation strategy. NVSCNF has strong chemical adsorption capacity and excellent electrocatalytic activity towards lithium polysulfides, enhancing redox kinetics. The abundant active sites of NVSCNF effectively regulate lithium deposition behavior and inhibit dendrite growth. The discharge specific capacity of the assembled lithium sulfur battery is 1305 mAh/g at 0.1C, and the capacity remains at 502.3 mAh/g after 800 cycles at a high current density of 5.0C. It can be stably cycled for more than 1000 hours at 0.5 mA/cm2, with an initial overpotential of only 18.3 mV.

Key words: Nb?VSe₆ membrane reactor, V-atom intercalation, Polysulfide conversion; Lithium deposition, Lithium-sulfur battery