TiO2@V2O5@CdS Heterostructures Modulate Adsorption and Bidirectional Conversion of Polysulfide in Lithium-Sulfur Batteries

Despite significant advancements in heterostructure catalysts to alleviate polysulfide shuttling for lithium-sulfur (Li-S) batteries, the importance of synergistic interactions among multiple materials remains overlooked. Herein, we report the rationally designed TiO2@V2O5@CdS heterostructures that take advantage of complementary structural and electronic properties to reinforce the adsorption to lithium polysulfides (LiPSs) and accelerate the sulfur redox kinetics. The modulation of the TiO2 nanoarray and V2O5 shell offers a steady interface and moderate adsorption to LiPSs, facilitating rapid aggregation of intermediates. Meanwhile, the optimized electronic structure achieved by the modification of CdS quantum dots enhances catalytic activity for bidirectional LiPSs conversion. Benefiting from the synergy of adsorptive modulated oxides and catalytic CdS, TiO2@V2O5@CdS heterostructures establish an efficient and sustainable adsorption-conversion of LiPSs with accelerated ion diffusion and reduced reaction energy barrier. Consequently, Li-S batteries with a TiO2@V2O5@CdS cathode exhibit excellent cycling stability over 1000 cycles with a degradation rate of 0.0413% per cycle at 1 C and an impressive areal capacity of 4.56 mA h cm-2 under a high sulfur loading of 4.5 mg cm-2. This work presents a complementary design of heterostructures that leverage structural and electronic synergies to improve the performance of Li-S batteries.