In-situ grown Ti3C2@TiO2 heterostructure enables high-performance lithium-sulfur batteries with polysulfides capture and catalytic conversion mechanism

The sluggish kinetics of the sulfur redox reaction (SRR) and the shuttling effect of lithium polysulfides (LiPSs) both restrict the practical application of lithium-sulfur (Li-S) batteries. Heterostructures, with their pronounced electroactivity and structural stability, showcase their potential as electrodes/functional separators for lithium-sulfur batteries. Herein, we proposed a bifunctional catalyst exhibiting strong adsorption and rapid catalytic conversion of LiPSs through in situ UV photocatalytic synthesis of Ti3C2@TiO2 heterostructure. The TiO2 nanoparticles act as the anchoring center for LiPSs, while the electrically conductive Ti3C2 ensures the rapid diffusion of these LiPSs from TiO2 to the catalytically active Ti3C2 layer across heterogeneous interfaces. The Li-S batteries with Ti3C2@TiO2-40 min-PP separator delivered a high initial capacity of 1283 mA<middle dot>h/g, which decreased slightly to 691 mA<middle dot>h/g after 200 cycles at 1C. This work advances the understanding of the synergistic effect of polysulfide adsorbents and conductive agents in inhibiting shuttle effects, and offers a method for designing polysulfide barriers in lithium-sulfur batteries.