Paracrystalline Engineering Activates the Catalytic Activity of Co ₃ O ₄ to Construct Highly Efficient Electrocatalyst for Lithium–Sulfur Batteries

Exposing unsaturated sites by modulating the lattice ordering is very efficacious in optimizing the catalytic performance of catalytic materials. Paracrystalline materials, which are intermediate between amorphous and crystalline materials, integrate some of the excellent properties of both and are rich in atomically ordered-disordered intersections with unsaturated sites. These characteristics enable paracrystalline materials to demonstrate potentially superior catalytic activity that efficiently facilitates the redox conversion of lithium polysulfides (LiPSs). However, paracrystalline materials have not been applied to improve the electrochemical performance of lithium-sulfur (Li-S) batteries, and the modulation mechanism by which their unique paracrystalline features affect the adsorption and catalytic performance of electrocatalysts for LiPSs remains unrevealed. Herein, a paracrystalline Co₃O₄ hollow flower-shaped sphere (PC-Co₃O₄ HFS) was engineered and employed as an efficient electrocatalyst for Li-S batteries. By modulation of the formation of the ordered-disordered intersections within the PC-Co₃O₄ HFS, numerous oxygen vacancies and active sites were created. This enables the PC-Co₃O₄ HFS to exhibit robust adsorption and catalytic capabilities, thereby effectively anchoring LiPSs and significantly accelerating the redox kinetics of sulfur species. Moreover, the Li⁺ transport behavior is also significantly improved by the PC-Co₃O₄ HFS. The batteries employing the PC-Co₃O₄ HFS exhibited a high discharge capacity of 818.74 mA h g^-1 at 4.0 C and retained a capacity of 545.06 mA h g^-1 after 500 cycles at 2.0 C, demonstrated excellent rate performance and cycling stability. Even at a high sulfur loading of 13.4 mg cm^-2, the batteries with the PC-Co₃O₄ HFS delivered an impressive areal capacity of 10.49 mA h cm^-2. This study successfully demonstrates the ability of paracrystalline materials to enhance the electrochemical performance of Li-S batteries, deepening the comprehending of the lattice ordering degree effect in Li-S electrochemistry.