Superior reaction kinetic behavior enabled by TiO2-x hierarchical structure host with polysulfide-shuttle control toward durable high-performance Li-S batteries

Lithium‑sulfur (Li-S) batteries are a highly promising energy storage technology due to their exceptionally high theoretical energy density. However, their practical implementation faces significant challenges, including sluggish redox kinetics and the troublesome shuttling of lithium polysulfides (LiPSs). In this work, a hierarchical TiO 2-x nanostructure was utilized as the sulfur host. Sulfur was uniformly integrated into the structure through a melt-diffusion infiltration process. The introduced oxygen vacancies in TiO 2-x provide strong chemical adsorption of polysulfides, effectively suppressing the shuttle effect and reducing active material loss. The nanoflower architecture-composed of interconnected nanosheets-offers a high specific surface area (104.45 m 2  g −1 ) and large pore volume (0.4698 cm 3  g −1 ). This design not only increases the number of accessible active sites but also helps accommodate volume changes during cycling. Furthermore, electron paramagnetic resonance (EPR) confirms the abundance of oxygen vacancies, which act as catalytic sites to enhance polysulfide anchoring and accelerate Li 2 S nucleation kinetics. As a result, the TiO 2-x -CNS@S cathode achieves a high initial discharge capacity of 1398 mAh g −1 at 0.1C and demonstrates remarkable long-term cycling stability. At 1C, it maintains an ultralow capacity decay rate of 0.054% per cycle over 1000 cycles. This dual-functional host design offers an effective and scalable strategy to simultaneously improve reaction kinetics and cycling durability in high-performance Li-S batteries.