Constructing honeycomb-structured LaCoO3 as an efficient polysulfide converter on the separator to achieve practical lithium-sulfur batteries.

A honeycomb-structured LaCoO 3 functional material with robust sulfur retention and catalytic performance was established as a highly efficient polysulfide converter on the separator to achieve practical Li-S batteries. [Display omitted] • Honeycomb-structured LaCoO 3 has been constructed as a highly efficient polysulfide converter on the separator. • The Li-S battery using LaCoO 3 -functioanlized separator gives a high capacity of 549 mAh/g after a long lifespan of 1000 cycles at 1C. • Under practical conditions of high sulfur content (64 %), lean electrolyte (7 μL mg−1), and high sulfur loading (7.96 mg cm−2), the Li-S battery maintains an areal capacity of 5.91 mAh cm−2 after 50 cycles. Owing to its remarkable energy density and specific capacity, lithium-sulfur (Li-S) battery has emerged as one of the most promising energy storage devices. Nevertheless, the shuttle effect and the sluggish conversion of polysulfides significantly impede the practical application of Li-S batteries. Hence, a LaCoO 3 functional material with a unique honeycomb structure was designed as an efficient polysulfide converter. The honeycomb-structured LaCoO 3 not only exhibits strong bonding energy towards polysulfides but also possesses abundant adsorption sites on its surface. The LaCoO 3 material also shows excellent catalytic properties to quickly convert the adsorbed and aggregated polysulfides, effectively suppressing the shuttle effect. Moreover, the honeycomb structure of LaCoO 3 can facilitate the rapid wetting and infiltration of the electrolyte. Consequently, the Li-S cell with LaCoO 3 functionalized separator provides an areal specific capacity of 3.10 mAh cm−2 after 150 cycles under high sulfur loading of 6.52 mg cm−2. Moreover, under practical conditions where the electrolyte content is as low as 7 μL mg−1 and the sulfur loading is 7.96 mg cm−2, the Li-S battery equipped with LaCoO 3 -separator can still provide an areal specific capacity of 5.93 mAh cm−2 after 50 cycles. [ABSTRACT FROM AUTHOR]