Enhanced catalytic activity and stability in lithium-sulfur batteries using Ti3C2Tx/NbSe2 heterostructured electrocatalysts

Lithium–sulfur (Li-S) batteries hold promise as high-energy storage systems; however, their practical application is hindered by challenges such as the shuttle effect of lithium polysulfides (LiPSs) and sluggish redox kinetics. In this study, we designed and synthesized Ti 3 C 2 T x /NbSe 2 electrocatalyst through in-situ hydrothermal growth and selenization steps. NbCl 5 was selenized to form Ti 3 C 2 T x /NbSe 2 , which was evaluated as a cathode material . The resulting Ti 3 C 2 T x /NbSe 2 material was precisely characterized by FESEM, TEM , XRD and XPS analyses . The Ti 3 C 2 T x /NbSe 2 exhibited a high BET specific surface area of 89.16 m 2 g −1 and a pore volume of 0.098 cm 3 g −1 , indicating enhanced adsorption capabilities for LiPSs. Electrochemical performance tests demonstrated the superior catalytic activity and redox kinetics of Ti 3 C 2 T x /NbSe 2 compared to those of pure Ti 3 C 2 T x and NbSe 2 . Cyclic voltammetry (CV) profiles indicated higher current densities, and Tafel plots revealed an increased exchange current density of 1.19 mA cm −2 for the Ti 3 C 2 T x /NbSe 2 . Li 2 S precipitation experiments showed an enhanced precipitation current density of 416.8 mA g −1 and a higher capacity of 198.6 mAh g −1 for the Ti 3 C 2 T x /NbSe 2 . The S/Ti 3 C 2 T x /NbSe 2 cathode exhibited outstanding rate capabilities, with capacities of 1389–716 mAh g −1 at current densities of 0.1–5 C, respectively. Moreover, it maintained a high discharge capacity of 954 mAh g −1 when the current density returned to 0.5 C. The long-term cycling stability was demonstrated with a capacity retention of 94.8 % over 550 cycles at 0.5 C, significantly outperforming the S/Ti 3 C 2 T x and S/NbSe 2 cathodes. Additionally, under a high sulfur loading of 6.5 mg cm −2 at 0.2 C, the S/Ti 3 C 2 T x /NbSe 2 cathode exhibited an initial area capacity of 6.13 mAh cm −2 , retaining a capacity of 3.45 mAh cm −2 after 300 cycles.