Defect-Engineered VS<sub>2</sub> Electrocatalysts for Lithium-Sulfur Batteries.
basic_science · Level V
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- Record sourced from PubMed, PMID 37530698.
- Also identified by DOI 10.1021/acs.nanolett.3c01838.
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Abstract
Defective two-dimensional transition metal dichalcogenides can be effective electrocatalysts for Li-S batteries, but the relationship between defect types and battery performance is unclear. In this work, we designed S vacancy-type S<sub>V</sub>-VS<sub>2</sub> and V self-intercalated-type V<sub>I</sub>-VS<sub>2</sub> and measured their catalytic activities in Li-S batteries. Compared with self-intercalating V atoms, S vacancies accelerated Li<sup>+</sup> diffusion and S<sub>V</sub>-VS<sub>2</sub> as a Li<sup>+</sup> "reservoir" promoted the sulfur conversion kinetics significantly. In addition, the presence of sulfur vacancies promoted the lithiation behavior of S<sub>V</sub>-VS<sub>2</sub> during discharge, leading to an enhancement of the catalytic ability of S<sub>V</sub>-VS<sub>2</sub>. However, this lithiation phenomenon weakened the catalytic activity of V<sub>I</sub>-VS<sub>2</sub>. Overall, S<sub>V</sub>-VS<sub>2</sub> had better adsorption and catalytic activity. Li-S batteries with S<sub>V</sub>-VS<sub>2</sub>-coated separators delivered high rate performance and excellent cycling stability, with a capacity decay rate of 0.043% over 880 cycles at 1.0 C. This work provides an effective strategy for designing efficient Li-S battery electrocatalysts using defect engineering.