Identifying the Evolution of Se-Vacancy-Modulated MoSe2 Pre-Catalyst in Li-S Chemistry.

作者：Menglei Wang, Zhong-Ti Sun, Haina Ci, Zixiong Shi, Lin Shen, Chaohui Wei, Yifan Ding, Xianzhong Yang, Jingyu Sun · 发表于：Angewandte Chemie · 年份：2021 · DOI：10.1002/anie.202109291 · 被引用次数：166 · 研究领域：Medicine、Chemistry

Witnessing compositional evolution and identifying actual catalytically-active moiety of electrocatalysts is of paramount importance in Li-S chemistry. Nevertheless, this field remains elusive by far. Herein, we report the scalable salt-templated synthesis of Se-vacancy-incorporated MoSe2 architecture (SeVs-MoSe2 ) and reveal the phase evolution of such defective pre-catalyst in working Li-S batteries. The interaction between lithium polysulfides and SeVs-MoSe2 is probed to induce the transformation from SeVs-MoSe2 to MoSeS. Furthermore, operando Raman spectroscopy/ex-situ X-ray diffraction measurements in combination with theoretical simulations verify that the effectual MoSeS catalyst could help promote the conversion from Li2S2 to Li2S, thereby boosting the capacity performance. Thus-derived Li-S battery accordingly exhibits satisfactory rate and cycling capability even under elevated sulfur loading and lean electrolyte conditions (7.67 mg cm-2 ; 4.0 μL mg-1S ). This work is anticipated to open an avenue for designing efficient electrocatalysts toward boosted sulfur chemistry and deepens the understanding of catalytic mechanisms of defective electrocatalysts.