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

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-01, Vol.20 (3), p.e2303192-n/a
• Main Authors: Zheng, Ming, Zhao, Junzhe, Wu, Wei, Chen, Runzhe, Chen, Suhao, Cheng, Niancai
• Format: Article
• Language: English
• Subjects: Adsorption; Chemisorption; Co/CoS2 heterojunction; Cobalt sulfide; Configurations; Doping; Electric fields; Electrocatalysts; Electrochemical analysis; Electronic structure; Electrons; Heterojunctions; Heterostructures; hollow structures; Lithium sulfur batteries; Polysulfides; Reaction kinetics; Redox reactions; S co‐doping; Substrates; Synergistic effect
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202303192

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. A hollow porous nanocage with Mott–Schottky heterostructure, nitrogen‐sulfur co‐doped carbon is presented. Theoretical modelings unveil that built‐in electric field in the heterojunction is constructed by the electron donor effect of the metal. The introduction of the heterogeneous component can modulate the electronic structure, provide reasonable adsorption to LiPSs, and delightful electrocatalytic ability for the high‐performance of Li–S batteries.