Enhancing sodium storage through tri-phase heterointerfaces in Co–Fe–MoSe2@N-doped carbon nanocubes with self-generated rich phase boundaries

Abstract

Transition metal selenides have received considerable research interest as conversion-type anodes owing to their impressive theoretical specific capacity and high conversion reaction efficiency. Nevertheless, the practical application of these materials is constrained by the low intrinsic conductivity and substantial volume changes during repetitive cycles, which leads to electrode structure deterioration, reduced cyclic stability, and poor rate performance. Herein, a trimetallic selenide Co–Fe–MoSe2@N-doped carbon composite with self-generated abundant phase boundaries was successfully designed using a straightforward co-precipitation method followed by a selenization process. The hybrid material, with its inherent self-generated electric field at the heterojunction surfaces, significantly improves the reaction kinetics. Moreover, the experimental results, complemented with density functional theory calculations, also illustrate that the enriched heterostructure boundaries provide ample electrochemical reaction active sites, thereby boosting charge transfer efficiency and mitigating the Na+ diffusion barrier. Remarkably, the composite exhibits excellent cyclic performance, achieving 322.4 mAh g−1 at 5 A g−1 after 1000 cycles, surpassing the performance of various other metal selenides. This innovative approach of creating abundant phase boundaries through the heterostructured ternary metal selenide presents a promising avenue for advancing the practical application of conversion-type anode materials.