Band Structure and Spin-State-Induced Electronic Configuration Regulation for Efficient Sulfur Redox Reaction

Abstract

Deciphering the relationship between electron configuration and catalytic activity is crucial for designing electrocatalysts that improve the efficient conversion of lithium polysulfides (LiPSs). In this study, amorphous ZnAl₂O₄ (referred to as A-ZnAl₂O₄) is designed with a high oxygen vacancy concentration. Experimental and theoretical analysis confirm that the Zn tetrahedral sites are sufficiently exposed, and the catalytic activity is significantly enhanced due to a narrow bandgap and a high spin state achieved through low coordination numbers and a disordered structure. Both the enhancement in electron transfer efficiency and reduction in reaction energy barriers accelerate the multi-phase transformation of LiPSs, resulting in impressive electrochemical performance with a capacity retention rate of 93.9% after 800 cycles at a high current density of 4 C. And the pouch battery with high sulfur loading of 4.5 mg cm⁻² and lean electrolyte at 8 µL mg⁻¹ exhibits high discharge capacity and stable cycling. This research deciphers the amorphization on modulating electronic structures to achieve enhanced electrocatalytic activity, providing a general strategy for designing unique atomic-scale band structures and spin states in multifunctional electrocatalysts.