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).