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

Abstract

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.