Interfacial Coupling toward Bismuth Sulfide/MXene Heterostructures Empowering Reversible Magnesium Storage

Bismuth-based compounds based on conversion-alloying reactions of multielectron transfer have attracted extensive attention as alternative anode candidates for rechargeable magnesium batteries (rMBs). However, the inadequate magnesium storage capability induced by the sluggish kinetics, poor reversibility, and terrible structural stability impedes their practical utilization. Herein, monodispersed Bi₂S₃ anchored on MXene has been prepared via a simple self-assembly strategy to induce the interfacial bonding of Ti-S and Ti-O-Bi. Unique superiority, including good electrical conductivity, high mechanical strength, and rapid charge transfer, is cleverly integrated together in the Bi₂S₃/MXene heterostructures, which endowed heterostructures with enhanced magnesium storage performance. Density functional theory calculations combined with kinetic behavior analyses confirm the favorable charge transfer and low ion diffusion barrier in hybrids. Furthermore, a stepwise insertion-conversion-alloying reaction mechanism is revealed in depth by <i>ex situ</i> investigations, which may also account for promoting performance. This work provides significant inspirations for constructing ingenious multicompositional hybrids by strong interfacial coupling engineering toward high-performance energy storage devices.