A HER-Inhibiting Layer Based on M-H Bond Regulation for Achieving Stable Zinc Anodes in Aqueous Zinc-Ion Batteries

A hydrogen evolution reaction (HER) Strategy is developed through material design to address the persistent challenge of the HER at the zinc anode. Unlike previous strategies, first-principles calculations are used to screen the low-coordinated Nb₂C MXene as the inhibitory medium. By taking advantage of the dual merits of its high |ΔG_*H| (1.03 eV) and excellent structural stability, the HER-Inhibiting layer Nb₂C@Znp is designed, which demonstrates the following key advancements: I) The onset potential for hydrogen evolution of 1.97 V (vs Zn²⁺/Zn) is achieved, representing a positive shift of 0.51 V compared with the bare zinc anode; II) It shows excellent cycling stability, being able to maintain for 2000 h at a current density of 2 mA cm⁻² and for 700 h at a current density of 10 mA cm⁻². III) The simultaneous inhibition of the hydrogen evolution reaction and the mitigation of dendrite growth are achieved through the regulation of the interfacial electron structure. Mechanistic studies indicate that the Nb₂C matrix weakens the bond energy of the M-H bond, and at the same time creates preferential migration channels for Zn²⁺, achieving a synergistic effect of inhibiting hydrogen adsorption and homogenizing zinc deposition, which greatly improves the CE and cycling stability.