Study On Electrochemical Reaction Mechanism Of Zinc-Nick Single-Flow Battery Based On Pore Size

With the increasing environmental pollution caused by the use of traditional fossil fuels,it is imperative to replace traditional fossil energy with renewable energy such as wind and solar energy.In order to achieve stable power supply for renewable energy such as wind and solar energy,it is of great significance to develop efficient energy storage technology.Compared with other energy storage technologies,liquid flow batteries have independent output power and capacity,flexible system design,long service life,stable operation,high energy efficiency and high reliability,and have broad application prospects.The zinc-nickel single-flow battery is a single-flow battery.It was proposed by the Institute of Chemical Defense in 2007.Its positive electrode is sintered nickel oxide,the negative electrode is made of nickel-plated punched steel strip as the base of the negative electrode.,and the electrolyte is an alkaline zincate solution.The zinc-nickel single-flow battery has the characteristics of simple system,high energy efficiency,low cost and long cycle life.It can provide an excellent solution for large-scale energy storage.In this paper,the lattice Boltzmann method(LBM)is used to study the coupling problem of flow mass transfer and electrochemical reaction in the porous positive electrode of zinc-nickel single-flow battery from the pore size.The electrochemical process of the porous positive charge of zinc-nickel single-flow battery is analyzed.Reaction mechanism.The main research work is as follows:1)A pore-scale LBM model describing the internal mass transfer and chemical reaction of sintered nickel electrodes under steady-state conditions is proposed,but only the variation ofOH~-concentration and its influence on electrochemical reactions are considered.The steady-state reaction process of the positive charge state at 50%during the charging process of the battery was simulated.The effects of the inlet electrolyte flow velocity,the charge current density and the porosity of the porous electrode on the mass transfer and chemical reaction in the electrode were investigated.2)A pore-scale LBM model for the internal mass transfer and chemical reaction of zinc-nickel single-liquid battery electrodes under steady-state conditions is proposed.Considering the factors such asOH~-,H~+and overpotential,a relatively complete LBM model of zinc-nickel single-flow battery was established.The steady state reaction process of the positive charge state at 50%was simulated during the charging process of the battery.The distribution of oh concentration,current density,solid phase proton concentration,solid-liquid potential and overpotential in the pore was obtained.The effects of inlet electrolyte flow velocity,charge current density and porosity of porous electrode on mass transfer and chemical reaction in the electrode were investigated.3)A pore-scale LBM model describing the internal mass transfer and chemical reaction of sintered nickel electrode under transient conditions was proposed.The transient reaction process during battery charging was simulated.The intra-poreOH~-concentration,current density and solid phase proton concentration were obtained.Distribution law.The effects of charging current density,porous positive electrode thickness and porous electrode porosity on mass transfer and chemical reaction in the electrode were investigated.Based on the above work,the mass transfer law and electrochemical reaction mechanism of porous positive electrode of zinc-nickel single-flow battery were obtained.