Application of indium-based compounds derived from metal-organic frameworks for sulfur cathode

Abstract

Lithium-sulfur (Li–S) batteries hold significant potential in the field of new energy storage owing to their ultrahigh theoretical energy density (∼2600 Wh kg⁻¹). The rational design of sulfur host is critical for enhancing their electrochemical performance. In this paper, a novel heterojunction material, denoted as In₂Se₃@In–C/CNTs, is synthesized through a two-step process involving carbonization and selenization of indium-based metal-organic frameworks (In-MOFs). The In₂Se₃ component, featuring 3D nanoflower structures, is uniformly grown on the In–C/CNTs with hexagonal tubular, providing a large specific surface area and abundant active sites for sulfur loading. Furthermore, the nanoflower-structured In₂Se₃ composed of thin nanosheets exhibits complementary structural integration with the 3D conductive network CNTs, which effectively restricts the dissolution and diffusion of polysulfides and facilitates rapid ion transport. In addition, the discharge specific capacity at 2 C can be maintained at 449.7 mAh g⁻¹ after 600 cycles, achieving a capacity decay rate of 0.061 % per cycle. After 100 cycles, the discharge specific capacity can still be maintained at 667.1 mAh g⁻¹ with the sulfur loading of 3.1 mg cm⁻². It can further promote the polysulfides chemisorption and prolong the cycle life of Li–S batteries. It certainly has practical significance to promote the development of Li–S batteries.