Synergistic Polysulfides Adsorption–Conversion with Mo2C–MoO2 Heterostructure for Kinetically Enhanced Lithium–Sulfur Battery

Abstract

Lithium–sulfur batteries (Li–S batteries) have a high theoretical capacity density. However, due to the solubility of long‐chain polysulfides migration between the positive and negative electrodes driven by concentration gradients, the cycle stability of lithium–sulfur batteries is compromised, hindering their practical application. To mitigate the shuttle effect and enhance the electrochemical performance of Li–S batteries, a hollow microflower (MF) Mo2C/MoO2 heterostructure is synthesized using a two‐step calcining method. The presence of a hetero‐interface improves the electrical conduction rate, facilitating more effective charge transfer at the interface between heterogeneous components. Additionally, the increased catalytic active sites enhance the conversion of polysulfides and promote the catalytic capability. As a result, Li–S batteries with H‐Mo2C/MoO2/nitrogen‐doped carbon MFs as additives in the cathode exhibit excellent rate performance and good cycling stability. After 100 cycles at 0.2C, the capacity remains at 1071.6 mAh g−1, with a capacity retention rate of 90.6%. Notably, the Li–S batteries demonstrate a capacity decay of only 0.011% per cycle over 1000 cycles at 1C, with a specific capacity of 790 mAh g−1 retained after the cycling process. In this work, a rational approach is provided to fabricating transition‐metal carbon‐oxide heterostructures with an optimized structure to enhance the performance of Li–S batteries.