Zincophilic MOF with N-functional groups for interfacial modification of stable aqueous zinc metal anodes†

Abstract

Rechargeable aqueous batteries using zinc as the anode have attracted more and more attention. However, the uncontrolled dendrite growth and hydrogen evolution reaction seriously hinder the performance of zinc anodes. In this work, a two-dimensional (2D) zinc-based MOF (ZHPCA) was synthesized by a simple solvothermal method, which is a Zn(II) coordination polymer with mixed ligands of nitrogen and oxygen donors (H-PCA). Using this MOF as the interface modification layer of the Zn electrode, the ZHPCA@UZn anode was prepared. The N-functional groups in ZHPCA can be used as binding sites for zinc ion deposition and promote their uniform deposition on zinc anodes. The modified layer also effectively inhibited hydrogen evolution and corrosion. It can be observed that the 40 μm ZHPCA@UZn (ZHPCA@UZn) has the longest cycle life exceeding 650 h with a low overpotential of about 46 mV. The zinc ion capacitor assembled by matching the ZHPCA@UZn anode with an activated carbon cathode maintained a specific capacity of 85 mA h g⁻¹ after 1000 cycles at 1 A g⁻¹. In conclusion, ZHPCA, the MOF selected in this work, can effectively protect the zinc anode, which provides certain inspiration for the selection of zinc anode coating materials in the future.