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

Abstract

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 LaCoO3 functional material with a unique honeycomb structure was designed as an efficient polysulfide converter. The honeycomb-structured LaCoO3 not only exhibits strong bonding energy towards polysulfides but also possesses abundant adsorption sites on its surface. The LaCoO3 material also shows excellent catalytic properties to quickly convert the adsorbed and aggregated polysulfides, effectively suppressing the shuttle effect. Moreover, the honeycomb structure of LaCoO3 can facilitate the rapid wetting and infiltration of the electrolyte. Consequently, the Li-S cell with LaCoO3 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 LaCoO3-separator can still provide an areal specific capacity of 5.93 mAh cm−2 after 50 cycles.