Carbonized-MOF as a Sulfur Host for Aluminum-Sulfur Batteries with Enhanced Capacity and Cycling Life

The rechargeable aluminum-sulfur (Al-S) battery is a promising next generation electrochemical energy storage system owing to its high theoretical capacity of 1672 mAh g(-1) and in combining low-cost and naturally abundant elements, Al and S. However, to date, its poor reversibility and low lifespan have limited its practical application. In this paper, a composite cathode is reported for Al-S batteries based on S anchored on a carbonized HKUST-1 matrix (S@HKUST-1-C). The S@HKUST-1-C composite maintains a reversible capacity of 600 mAh g(-1) at the 75th cycle and a reversible capacity of 460 mAh g(-1) at the 500th cycle under a current density of 1 A g(-1), with a Coulombic efficiency of around 95%. X-ray diffraction and Auger spectrum results reveal that the Cu in HKUST-1 forms S-Cu ionic clusters. This serves to facilitate the electrochemical reaction and improve the reversibility of S during charge/discharge. Additionally, Cu increases the electron conductivity at the carbon matrix/S interface to significantly decrease the kinetic barrier for the conversion of sulfur species during battery operation.