Dynamic coupling mechanism in NbSe2/MoSe2 heterojunctions for enhanced temperature adaptability of lithium-ion batteries

Abstract

While transition metal selenides (TMSes) are attractive anode materials for lithium-ion batteries (LIBs) due to their high capacity, they do suffer from sluggish kinetics, dissolution, and shuttling of intermediate phases, inducing rapid degradation of cycling performance. Herein, a coupling strategy based on NbSe₂/MoSe₂ heterojunction anodes and electrolyte adaptability is proposed: the compatible electrolyte facilitates the enrichment of fluoroethylene carbonate (FEC) at the heterojunction interface, thereby enabling the in situ formation of a LiF-rich solid electrolyte interphase (SEI) This SEI dynamically couples with the built-in electric field of the heterojunction, significantly reducing the desolvation energy barrier of Li⁺ and interfacial migration resistance, thus optimizing the interfacial ion transport kinetics. Density functional theory calculations, molecular dynamics simulations, and electrochemical tests collectively confirm that this dynamic coupling mechanism between the heterojunction and the electrolyte not only accelerates the interfacial kinetics of Li⁺ but also effectively suppresses the dissolution and shuttling of lithium polyselenides (Li₂Se_x). Notably, the application of this strategy enables efficient participation in electrochemical reactions even under low-temperature conditions, thereby imparting enhanced temperature adaptability. The NbSe₂/MoSe₂ half cell demonstrates an excellent capacity of 862.7 mAh g⁻¹ at 25 °C and 487.8 mAh g⁻¹ at −25 °C. Under the cycling conditions of 0.1 A g⁻¹ discharge and 1.0 A g⁻¹ charge, the capacity remains at 93.1% and 88.6% after 100 cycles, respectively. This work provides an effective strategy for enhancing the interfacial kinetics and temperature adaptability of TMSe anodes.