The utilization of catalysts in lithium−sulfur batteries has proven to be an efficacious avenue for enhancing the kinetics of polysulfide conversion. Specially, the size and electronic structure of catalysts play a pivotal role in harnessing the active sites and intrinsic catalysis activity. Outstanding MoSe2 and NbSe2 are selected from 16 universal transition metal selenides based on the proposed binary descriptor. Then, an alloying strategy is devised to prepare Mo0.25Nb0.75Se2 flakelets for further improvement of the intrinsic catalysis. The integration of density functional theory calculations and electrochemical analysis demonstrates that alloying Mo with Nb can regulate the surface energy and indexes of band match and lattice mismatch, thereby enabling Mo0.25Nb0.75Se2 to possess a small size, suitable adsorption energy and low reaction energy barrier. This optimization enhances the catalysis of sulfur reduction/evolution reaction and the reversible deposition/stripping of lithium. Consequently, an assembled Ah-level pouch cell is realized with dramatic cycle stability. With the electrolyte/sulfur ratio of 2.36 μL mg S–1, the cell can deliver a high energy density of up to 505.4 Wh kgtotal−1. This work pioneers a universal strategy for sculpting the geometric configurations and electronic structures of catalysts, to achieve enhanced catalytic activity and precise interpretation of structure−activity relationships.

中文翻译：

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调节 Mo0.25Nb0.75Se2 尺寸和电子结构的合金化策略，实现高性能锂硫电池


在锂硫电池中使用催化剂已被证明是增强多硫化物转化动力学的有效途径。特别是，催化剂的尺寸和电子结构在利用活性位点和本征催化活性方面起着关键作用。根据所提出的二进制描述符，从 16 种通用过渡金属硒化物中选出了出色的 MoSe2 和 NbSe2。然后，设计了一种合金化策略来制备 Mo0.25Nb0.75Se2 薄片，以进一步改善本征催化。密度泛函理论计算与电化学分析的结合表明，Mo 与 Nb 合金化可以调节表面能以及带匹配和晶格失配的指标，从而使 Mo0.25Nb0.75Se2 具有体积小、吸附能适宜、反应能势垒低。这种优化增强了硫还原/析出反应的催化和锂的可逆沉积/剥离。因此，组装的 Ah 级软包电池具有极高的循环稳定性。电解质/硫比为 2.36 μL mg S–1，该电池可提供高达 505.4 Wh kgtotal-1 的高能量密度。这项工作开创了一种通用策略来雕刻催化剂的几何构型和电子结构，以实现增强的催化活性和对结构-活性关系的精确解释。