Aqueous Zinc Sulfate Flow Through a Copper Mesh Anode Improves Zinc Metal Electrodeposition Morphology and Impedance

Abstract

The cycle life and power density of Zn metal batteries depend on the anode electrodeposition morphology, including the formation of metal dendrites, and impedance, respectively. This paper investigates the influence of aqueous ZnSO4 electrolyte convection through a copper mesh anode on Zn electrodeposition morphology and current densities. Electrochemical experiments in a specially designed flow-through cell with a Zn metal cathode reveal that the electrolyte flow from the cathode through the anode improves Zn deposition morphology and reduces impedance at concentrations ranging from 0.01 to 1 mol l−1. Small flow rates at millimeters per second double the current densities. The electrodeposition morphology and current density are positively impacted at Peclet number larger than 1. At these flow rates, the Zn plating is more smooth, compact, uniformly deposited around the wire, and dense than that in the stagnant electrolyte. Zn-Cu asymmetric cell cycling tests at 50 mA cm−2 show that flow-through electrolyte can significantly increase the cell lifespan from 18 cycles in static electrolyte to 1300 cycles at a flow rate of 0.5 mm s−1. Numerical analysis illustrates that the flow-through electrolyte replenishes consumed zinc ions at the electrode surface and suppresses dendrite growth by maintaining a uniform current density distribution.