The Catalytic Effect of C3B-CP and SiC-CP Heterojunctions in Accelerating the Sulfur Conversion Kinetics of Sodium-Sulfur Batteries.

The practical application of room-temperature sodium-sulfur (Na-S) batteries is hindered by the polysulfide shuttle effect and sluggish sulfur conversion kinetics. This study systematically investigated the anchoring and catalytic capabilities of two-dimensional carbide monolayers (C3B, CP, SiC) and their van der Waals heterojunctions towards sodium polysulfides (NaPSs) using first-principles calculations. While CP monolayer demonstrates superior intrinsic catalytic activity for Na2S decomposition and Na+ diffusion, the main highlight of this work lies in the strategic construction of C32S decomposition and Na3+ diffusion, the main highlight of this work lies in the strategic construction of C3B/CP and SiC/CP heterojunctions. These heterostructures achieve precise regulation of the catalytic pathway, drastically reducing the Na2S dissociation barrier to 0.33 and 0.11 eV and the Na+ migration barrier to 0.04 and 0.15 eV, respectively. The interfacial synergy within the heterojunctions enhances charge transfer and optimizes the reaction energetics. Our findings verify the feasibility of a heterojunction engineering strategy for developing high-performance sulfur hosts and provide a fundamental understanding of the catalytic regulation mechanism in Na-S batteries.