MOF-derived ultrathin carbon nanosheets integrated with telluride nanoparticles: synergistic polysulfide adsorption and catalytic sites for enhanced sulfur redox reactions†

Abstract

Two-dimensional (2D) nanocarbon-based materials with controllable pore structures and hydrophilic surfaces exhibit significant potential in various applications. However, traditional methods often encounter challenges in achieving these 2D carbon nanomaterials effectively. In this study, we present a scalable approach for the preparation of porous ultrathin nitrogen-doped carbon nanosheets decorated with ultrafine FeTe₂ nanoparticles (FeTe₂/CN), derived from metal–organic frameworks (MOFs) through a mild and modifier-free synthesis strategy. This graphene-like structure serves as a promising cathode material to address complex challenges in lithium–sulfur batteries (LSBs). Experimental results and density functional theory (DFT) calculations highlight the distinct advantages of this structure: (1) synergistic adsorption occurs through the lithiophilic sites of CN and the sulfiphilic sites of FeTe₂, efficiently capturing lithium polysulfides (LiPS); (2) enhanced conductivity of the CN nanosheets, combined with the robust spin state effect of FeTe₂, accelerates electron transfer and reduces energy barriers, thereby improving sulfur redox reaction (SRR) kinetics; (3) the graphene-like CN nanosheets provide numerous active sites and mitigate volume expansion during cycling. Consequently, LSBs based on S@FeTe₂/CN cathodes exhibit high initial capacity, exceptional rate performance, and outstanding stability. This work offers a novel strategy for preparing 2D nanocarbon-based materials with highly exposed active sites to enhance SRR efficiency.