Co/CoS₂ Heterojunction Embedded in N, S‐Doped Hollow Nanocage for Enhanced Polysulfides Conversion in High‐Performance Lithium–Sulfur Batteries

Abstract

Modulating the electronic configuration of the substrate to achieve the optimal chemisorption toward polysulfides (LiPSs) for boosting polysulfide conversion is a promising way to the efficient Li-S batteries but filled with challenges. Herein, a Co/CoS₂ heterostructure is elaborately built to tuning d-orbital electronic structure of CoS₂ for a high-performance electrocatalyst. Theoretical simulations first evidence that Co metal as the electron donator can form a built-in electric field with CoS₂ and downshift the d-band center, leading to the well-optimized adsorption strength for lithium polysulfides on CoS₂ , thus contributing a favorable way for expediting the redox reaction kinetics of LiPSs. As verification of prediction, a Co/CoS₂ heterostructure implanted in porous hollow N, S co-doped carbon nanocage (Co/CoS₂ @NSC) is designed to realize the electronic configuration regulation and promote the electrochemical performance. Consequently, the batteries assembled with Co/CoS₂ @NSC cathode display an outstanding specific capacity and an admirable cycling property as well as a salient property of 8.25 mAh cm^-2 under 8.18 mg cm^-2 . The DFT calculation also reveals the synergistic effect of N, S co-doping for enhancing polysulfide adsorption as well as the detriment of excessive sulfur doping.