Study On The Internal Reaction Mechanism Of Positive Electrode In Zn/ni Single Fluid Battery By Lattice Boltzmann Method

In recent years,the scale of renewable energy development and utilization is expanding,and the research and application of energy storage technology is increasingly widespread.Different energy storage technologies have their own advantages and disadvantages.Redox flow battery is considered to be the trend of future energy storage technology.The abbreviation of redox flow battery is RFB.According to the structural characteristics of its ion exchange membrane,it can be divided into two fluid cells and one fluid battery.Zn/Ni single liquid flow battery is a single liquid current battery without ion exchange membrane.It was put forward in 2007 by the Research Institute of chemical defense.It uses the sintered nickel oxide as the positive pole of the battery,with zinc as the anode of the battery and the alkaline zincate solution.Zn/Ni single flow battery has the advantages of low cost,simple structure and long cycle life.It can provide a cost-effective solution for large-scale energy storage.In this paper,the coupling of the percolation,mass transfer and electrochemical reaction in the porous electrode of the nickel sintered nickel is explored based on the lattice Boltzmann method.The main research work of this paper is as follows: 1)The process based QSGS reconstruction method is described in detail.According to the structural characteristics of the QSGS porous media reconstruction method,the reasons for its non applicability in the construction of some porous media with specific structures are analyzed.Two improved ideas were put forward,and a controlled porous media virtual reconstruction method based on improved four parameter random growth method was formed for sintered nickel in Zn/Ni single liquid flow battery.And the digital porous medium model of sintered nickel was reconstructed by the improved method.2)A reasonable calculation area is drawn near the positive pole of single channel of a zinc nickel single liquid flow battery,and the flow field in the calculated area is solved by using the lattice Boltzmann method.The influence of inlet velocity,runner width and porous media skeleton morphology on the internal flow of sintered nickel cathode is investigated.3)A pore scale model of mass transfer and chemical reaction of the sintered nickel electrode was proposed.After a certain simplification,the numerical calculation was made using the mass transfer model of the lattice Boltzmann method to simulate thesteady state reaction process of the charge and discharge of the battery at 50%.The distribution of reactive ion concentration,the surface reaction current density and the current density flux in the pore were obtained.The effects of inlet velocity and discharge current density on mass transfer and reaction were investigated.Based on the above work,some forward-looking results have been made,which proves the feasibility of the research method and the rationality of the technical route,laying the foundation for further and more detailed exploration of the mechanism of electrode electrochemical reaction.