Structural Modification of Negative Electrode for Zinc–Nickel Single–Flow Battery Based on Polarization Analysis

Abstract

In order to improve the power density of zinc-nickel single-flow battery (ZNB), the polarization distribution characteristics and influence mechanism of the battery are investigated. In this paper, polarization of the positive and negative electrodes and the overall polarization of the battery are analyzed for the first time based on the three-dimensional transient model of ZNB. The accuracy of the simulation model is verified by experiments, and then the polarization distribution in a zinc-nickel single-flow battery with nickel-plated steel strip (NS) as the negative electrode is systematically investigated. Due to the serious polarization phenomenon of NS as negative electrode, in order to reduce the polarization and improve the performance of zinc anode, porous nickel foam (NFs) is used as negative electrode. The optimized thickness and porosity of NF under different application current density and electrolyte flow rate are screened out, and the influence rules of current density and electrolyte flow rate on the optimum NF parameters are summarized. When the electrode thickness reaches a certain level, increasing the electrode thickness will lead to the increase of over-potential on the contrary.