Facile sulfur chemistry assisted carbon reconfiguration for efficient potassium ion electrochemical storage

Abstract

Carbon-based materials are commonly used as anodes for potassium-ion batteries due to their high conductivity and stable cycling performance. However, their practical application is greatly hindered by their low capacity. Herein, we introduce facile sulfur chemistry including thioether bonds and CoS₂ into a nitrogen-oxygen co-doped partially graphitized carbon skeleton (NOGC), while the extra reconfiguration process of carbon assists forming the CoS₂@R-NOGC composites. The reconfigured NOGC (R-NOGC), enriched with highly electronegative elements (N, O, S), significantly enhances the reversible potassium ion storage capacity. The ordered carbon structure provides more efficient ionic transport pathways, thereby improving K⁺ transport efficiency. Moreover, layered CoS₂ acts as additional ion transport channels and active sites, further enhancing ion mobility and storage capacity. R-NOGC also promotes the reconstruction and repair of the solid electrolyte interface (SEI) layer to form a more robust interface. As a result of the synergistic effect between R-NOGC and CoS₂, it exhibits excellent anode performance, including a high reversible capacity (314.0 mAh/g at 0.1 A/g) and long-term stability (250.3 mAh/g at 0.5 A/g after 1,000 cycles). This work presents a novel strategy for designing and synthesizing high-performance anode materials for potassium-ion batteries, significantly enhancing both capacity and cycling stability.