Multilayer design of core-shell nanostructure to protect and accelerate sulfur conversion reaction

초록

Although a core-shell design has been suggested to maximize reversible redox reaction of conversion-type electrode materials inside a shell, it is challenging to fulfill the complicated prerequisites collectively. This paper proposes a rational core-shell design composed of single-atom catalytic and protective multilayers for sulfur conversion reaction. A hydrogen bond-based supramolecular network incorporates Fe ions by metal-phenolic coordination, accelerating sluggish kinetics. The polypyrrole layer protects the entire structure to suppress the migration of polysulfides and withstand large volume changes. Comprehensive investigation demonstrates that core-shell sulfur nanostructures preserve the structural integrity and electrocatalytic effect during discharge/ charge. The resulting electrodes enable outstanding rate capability and stable cycling performance. Furthermore, the areal capacity of higher sulfur loading cells surpasses current Li-ion batteries even at 1 C. This work reactivates the core-shell strategy as a design guideline for viable next-generation electrode materials.

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