3D hollow spheres comprising MXene/g-C3N4 heterostructre for efficient polysulfide adsorption and conversion in high-performance Li-S batteries

Abstract

Suppressing the lithium polysulfides (LiPSs) shuttle and facilitating ion and charge transport in the electrode component resulting in effective sulfur conversion, is essential for the efficient functioning of lithium-sulfur (Li-S) batteries have substantial sulfur loading. In this study, a multifunctional cathode material based on a three-dimensional MXene and g-C₃N₄ hollow spheres framework was designed. This design aimed to create a conductive Platform with high absorptive and catalytic capability that would boost the performance of Li-S batteries in practical operating conditions. At the electrode level, the 3D hollow spherical architecture offers a large surface area to achieve high sulfur loading, preserves structure integrity in the electrode over significant volume changes of sulfur species, and facilitates diffusion of Li⁺ and electrolyte flow. At the molecular level, the pyridinic structure of g-C₃N₄ and the MXene conductive platform allows for fast sulfur conversion. The cathode, consisting sulfur ratio of 80%, exhibits a remarkable primary specific capacity of 1350.6 mAhg⁻¹ at 0.1C. It retains 877.2 mAhg⁻¹ after 100 cycles, showing a 65.2% retention rate. Furthermore, it exhibits exceptional electrochemical properties in terms of rate performance, giving a capacity of 632.5 mAhg⁻¹ at a current of 4C. Our findings may have future technological consequences since they may speed the development of cost-effective and more efficient electrode materials for Li-S batteries.