Homogeneous deposition of zinc on three-dimensional porous copper foam as a superior zinc metal anode

Metal zinc, with the advantages of low cost, low redox potential, and high capacity, is an ideal anode for aqueous zinc-ion batteries. Nonetheless, the inferior plating/stripping Coulombic efficiency and poor reversibility hinder its practical applications. To address the drawbacks, the zinc nucleation overpotential of different substrates is systematically investigated in asymmetric cells for the first time to confirm the suitable substrate with highly reversible plating/stripping behavior. As a result, Cu foam presents the low zinc nucleation overpotential of 65.2 mV and superior plating/stripping Coulombic efficiency close to 100%. Meanwhile, Cu foam is optimized as the carrier for the deposition of metallic zinc and the preparation of the Zn@Cu foam anode through the electrochemical deposition method. Besides, the Zn@Cu foam anode holds the low initial polarization voltage and stable voltage hysteresis profile with negligible voltage polarization in the symmetric cell. Furthermore, coupled with the beta-MnO2 cathode, it could exhibit an outstanding cycling ability with a capacity of 172.8 mA h g(-1) after 600 cycles at 1 A g(-1) in the full cell, corresponding to an extremely low decay rate of 0.0218% per cycle.