Self-recovery catalysts of ZnIn2S4@In2O3 heterostructures with multiple catalytic centers for cascade catalysis in lithium−sulfur battery

The "shuttle effect" of soluble lithium polysulfides (LiPSs) in lithium-sulfur (Li-S) batteries can lead to sluggish kinetics of sulfur redox reactions and rapid capacity degradation, significantly limiting the practical application of Li-S batteries on a large scale. Herein, the cascade catalysis is achieved based on a self-recovery catalyst with multiple catalytic centers through a ZnIn2S4-In2O3-ZnIn2S4 sandwich-like structure to realize the tandem redox of S8 to Li2S. Specifically, the outer ZnIn2S4 nanosheet network can preferentially adsorb S8, and the middle In2O3 acts as an adsorption mediator to ensure the adsorption and conversion of S8 to long-chain Li2S6/Li2S4, and then the inner ZnIn2S4 can further catalyze the conversions from long-chain Li2S4 to short-chain Li2S2/Li2S. Reversibly, the ZnIn2S4 is better in decreasing the energy barrier of Li2S dissolution, and further converting it into elemental sulfur (S8). During this process, the In/O and In/Zn active sites are re-exposed by alternating catalytic mode to achieve the self-recovery of active site, thereby enhancing long-term catalytic activity. This work demonstrates that cascade catalysis can be achieved by self-recovery catalysts with multiple catalytic centers for LiPSs, providing novel insights into the design of multi-functional catalysts to rationally regulate LiPSs' redox reactions