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ABSTRACT Lithium‐sulfur (Li‐S) batteries are promising for high‐energy‐density storage, but their performance is limited by sluggish lithium polysulfide (LiPS) conversion kinetics. Here, we tackle this issue by synthesizing ultrafine truncated octahedral TiO 2 nanocrystals (P‐O v ‐TiO 2), featuring specific 101 facets and dual defects—phosphorus doping and oxygen vacancies. Acting as an efficient electrocatalyst in the separator, P‐O v ‐TiO 2 exhibits superior catalytic properties, where oxygen vacancies modulate the electronic structure, enhancing electron enrichment and charge transfer; phosphorus doping tailors the d ‐band center of the catalyst, strengthening Ti‐S interactions between the 101 facets and LiPSs. As a result, Li‐S coin cells modified with P‐O v ‐TiO 2 achieve a high specific capacity of 895 mAh g −1 at 5 C and exhibit a minimal decay rate of 0. 14% per cycle over 200 cycles. Furthermore, Li‐S pouch cells deliver a high capacity of 1004 mAh g − 1 at 0. 1 C under lean electrolyte conditions. This study elucidates the mechanisms of charge states on specific crystal planes and deepens our understanding of dual‐defect engineering in Li‐S electrochemistry, offering a promising approach for developing efficient and cost‐effective catalysts for Li‐S battery applications.
Yang et al. (Fri,) studied this question.