A High-Efficiency CoSe Electrocatalyst with Hierarchical Porous Polyhedron Nanoarchitecture for Accelerating Polysulfides Conversion in Li–S Batteries

Lithium–sulfur (Li–S) batteries are recognized as promising candidates for next-generation electrochemical energy storage systems owing to their high energy density and cost-effective raw materials. However, the sluggish multielectron sulfur redox reactions are the root cause of most of the issues for Li–S batteries. Herein, a high-efficiency CoSe electrocatalyst with hierarchical porous nanopolyhedron architecture (CS@HPP) derived from a metal–organic framework is presented as the sulfur host for Li–S batteries. The CS@HPP with high crystal quality and abundant reaction active sites can catalytically accelerate capture/diffusion of polysulfides and precipitation/decomposition of Li₂S. Thus, the CS@HPP sulfur cathode exhibits an excellent capacity of 1634.9 mAh g⁻¹, high rate performance, and a long cycle life with a low capacity decay of 0.04% per cycle over 1200 cycles. CoSe nanopolyhedrons are further fabricated on a carbon cloth framework (CC@CS@HPP) to unfold the electrocatalytic activity by its high electrical conductivity and large surface area. A freestanding CC@CS@HPP sulfur cathode with sulfur loading of 8.1 mg cm⁻² delivers a high areal capacity of 8.1 mAh cm⁻² under a lean electrolyte. This work will enlighten the rational design of structure–catalysis engineering of transition-metal-based nanomaterials for diverse applications.