Sulfur Microspheres Encapsulated in Porous Silver-Based Shell with Superior Performance for Lithium-Sulfur Batteries
Graphical Looking for the silver lining : In-situ encapsulation of sulfur within a highly conductive metallic shell with desirable thickness and pore sizes is achieved for the first time using the chemical plating method, which provides a new avenue to suppress the polysulfide shuttling issue and improves the internal conductivity for the S cathode in lithium-sulfur batteries. The lithium-sulfur system is considered as one of the next-generation batteries owing to its low-cost and high theoretical energy density. However, the poor conductivity of sulfur, undesirable dissolution, and shuttling of lithium polysulfides are still main challenges for a practical application. Herein, a chemical plating method was developed to encapsulate sulfur microspheres within a porous Ag-based thin shell of ca. 67 nm in thickness (denoted as S@Ag microcomposites). The sulfur content in the S@Ag particles is 89 wt%. With such structural and compositional merits, the core-shell composites can effectively facilitate the electron transfer and alleviate the polysulfide dissolution. When utilized as cathode in Li−S batteries, the S@Ag microcomposites exhibit good electrochemical performance, featured by an initial charge capacity of 1231 mAh g −1 and a capacity of 922 mAh g −1 after 100 cycles at 0.2 C. The electrochemical performance of commercial S particles was also improved after treated by this chemical plating method. This study provides a simple and novel approach to fabricate S composite cathodes with high S content and promising electrochemical properties.
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