Electrochemical characterization
Tafel curves: The Tafel tests were carried out in a three-electrode setup with 2M ZnSO4 as the electrolyte, Zn or Zn@Zn2(bim)4 as the working electrode, and Ag/AgCl as the reference electrode, and platinum (Pt) mesh as the counter electrode. Cyclic voltammetry(CV): The CV tests were carried out in the same three-electrode setup with Cu or Cu@Zn2(bim)4 as the working electrode. Chronoamperometry (CA ): The CA test was also conducted in the three-electrode setup. The working electrode is Zn or Zn@Zn2(bim)4, and the reference electrode is Zn. The other electrochemical tests were conducted in CR2025 coin cells assembled with a glass fiber separator and 2M ZnSO4 as the electrolyte. The electrochemical impedance spectroscopy (EIS) and Zn plating/striping performance were tested in Zn//Zn or Zn@Zn2(bim)4//Zn@Zn2(bim)4symmetric cells. The CE of anodes was measured in Zn//Cu or Zn//Cu@Zn2(bim)4 cells with a current density of 0.5 mA cm-2 for 1h. The electrochemical performance of full cells (Zn//MnO2 or Zn@Zn2(bim)4//MnO2) were tested under different current densities with cutoff voltages of 1.0 and 1.8V and 2M Zn2SO4 and 0.2 M MnSO4 as electrolyte. Tafel curves, CV, CA and EIS were conducted in electrochemical workstation (SP-200, Biologic). The frequency for EIS test ranges from 100 kHz to 10 mHz with an amplified voltage of 10 mV. The Zn plating/striping performance, CEs of Zn anode, and full cell tests were carried out in battery testing system (Neware).