Rational Design of MXene/MOF Heterostructures to Suppress Hydrogen Evolution and Mitigate Dendrite Growth in Aqueous Zn-Ion Batteries: Insights from DFT and MD Studies

The metal zinc anode is a promising candidate for large-scale aqueous Zn-ion batteries due to its superior safety, affordability, and excellent theoretical capacity. Recent efforts in Zn anode development have primarily focused on mitigating dendrite growth and suppressing the hydrogen evolution reaction (HER) by integrating protective layers into anode composites. Herein, we apply a six-step, multiscale modeling workflow: (1) forming the stable heterostructure, (2) electronic properties analysis, (3) screening of Zn vs H₂O adsorption, (4) determining the HER limiting potential (<i>U</i>_L), (5) calculating the Zn diffusion barrier, and (6) simulating explicit-electrolyte effect, to guide the design of 2D/2D MXene/MOF protective coatings. Three heterostructures are examined: Ti₃C₂F₂/CuHHB, Ti₃C₂F₂/CuHIB, and Ti₃C₂O₂/CuHHB (abbreviated F/HHB, F/HIB, and O/HHB). All remain intact during 1 ps ab initio dynamics at 300 K and retain metallic conductivity. The O/HHB interface is the most effective; it favors Zn adsorption over H₂O by 0.74 eV and raises the <i>U</i>_L of HER to -2.41 V at the interface, making it more effective than Zn(002). In addition, classical MD simulations in 1 M ZnSO₄ show that a large hydrogen-bonded network in the HHB pore further hinders the HER. The study singles out Ti₃C₂O₂/CuHHB, with O termination and O donor atom, as a potential coating candidate and provides a transferable computational protocol for developing MXene/MOF skins that both suppress HER and mitigate dendrite growth.