Introducing anti-hydrogen evolution sites by hydrophilic metalloporphyrin coatings for stabilizing Zn metal anodes

Realizing Zn metal anodes with long lifespan performance is a prerequisite for the commercialization of Zn-ion batteries, which is limited by severe water erosion, side reactions and dendrite formation. Herein, a series of hydrophilic metalloporphyrin coatings were employed to stabilize the Zn anode by screening their central metal sites from Mn to Zn. Among them, central copper (Cu²⁺) site significantly blocks the competitive hydrogen evolution reaction (HER) by elevating the adsorption barrier for the hydrogen proton intermediate (H*), suppressing both Heyrovsky and Tafel steps. Consequently, the HER overpotential of CuTCPP@Zn is increased while parasitic side reactions are reduced. Furthermore, the enhanced zincophilicity of CuTCPP@Zn facilitates a high Zn²⁺ transfer number of 0.70, which promotes uniform nucleation and deposition. As a result, CuTCPP@Zn delivers a stable cycling life exceeding 1460 h at 1 mA cm^-2 and 453 h even at 5 mA cm^-2. This work provides insights for precisely altering intrinsic HER activity by regulating central metal sites of hydrophilic metalloporphyrin coatings from a thermodynamic perspective, thereby realizing the construction of stable Zn metal anodes.