Constructing a built-in electron reservoir to dynamically coordinate bidirectional polysulfides conversion for lithium-sulfur batteries with a wide working temperature range

Empowering electrocatalysts with appropriate electrocatalytic activity is imperative to improve the electro-chemical properties of lithium-sulfur (Li-S) batteries. Nevertheless, the intricate multi-step conversion pathways of sulfur concomitant with disparate electrokinetic processes make it challenging to establish a tried-and-true strategy to dynamically modulate the electronic structure of electrocatalysts and thus precisely catalyze the specific conversion step. Herein, a built-in electron reservoir is rationally envisaged to refashion the occurrence mechanism of synchronously coordinated electrocatalysis in bidirectional sulfur redox processes. As a proof-of -concept investigation, a facile incorporation of selenium (Se) into lithium polysulfides (LiPSs) is conscripted to recognize the inherent impetus for LiPSs reduction and Li2S decomposition. In conjunction with synchrotron -based characterizations and theoretical calculations, a streamline sulfur redox triggered by Se with a synchro-tuned electronic structure is identified. Specifically, the Se in LiPSs-Se could donate electrons to prompt ample LiPSs reduction in the discharge process, while the Se in the formed Li2S-Se functions as an electron re-ceptor to extract electrons from Li2S for rapid Li2S decomposition in the following charge process. The proposed built-in electron reservoir offers an elegant avenue for dynamically coupling distinct electrokinetics via endo-genic electronic structure modulation aiding in circumventing sophisticated interfacial architecture arrangement in contemporary multi-heterogeneous electrocatalysts.

Automated summary

Empowering electrocatalysts with proper electrocatalytic activity is crucial for improving the electro-chemical properties of Li-S batteries. In this study, a built-in electron reservoir is proposed to modulate the occurrence mechanism of electrocatalysis in bidirectional sulfur redox processes. By incorporating selenium into lithium polysulfides, the reduction and decomposition reactions of LiPSs and Li2S are enhanced. The presence of selenium can effectively tune the electronic structure of the sulfur redox reaction, thus improving the catalytic activity of the electrocatalyst.