Redox-Active Interlayer with Gradient Adsorption and Catalytic Conversion Functionality for High-Sulfur-Loading Lithium-Sulfur Batteries

Abstract

Achieving high-sulfur-loading lithium–sulfur batteries with exceptional cycling stability is pivotal for their commercial deployment. This necessitates the rational engineering of advanced electrode materials and optimized cell configurations. This study utilizes a parallel-channel-structured N-doped carbon-fiber network embedded with atomically dispersed Co-N-C active sites to design a redox-active interlayer with gradient adsorption and catalytic conversion functionalities. The N-doped carbon-fiber matrix enhances electronic conductivity and serves as a robust polysulfide immobilizer, suppressing the shuttle effect and extending cycling lifespan. Concurrently, the atomically dispersed Co-N-C active sites introduce abundant sulphurophilic centers, strengthening polysulfide anchoring and accelerating redox kinetics. Additionally, the parallel-channel architecture maximizes adsorption site density, enhances electrolyte permeation, and optimizes ion transport, facilitating ultrafast charge transfer and efficient electrochemical reactions. The optimized Super P/S60-porous carbon-fiber/C67 composite/S system, with an ultrahigh sulfur loading of 15.6 mg cm−2, demonstrates extraordinary electrochemical stability, maintaining a reversible capacity of 540 mAh g−1 over 100 cycles. Furthermore, a pouch cell with a higher sulfur loading of 23.3 mg cm−2 delivers notable capacity retention of 592 mAh g−1 after 20 cycles, highlighting the effectiveness of this innovative cell architecture for high-energy-density lithium–sulfur batteries for next-generation energy storage technologies. © 2025 The Author(s). Small Structures published by Wiley-VCH GmbH.