Development of a zinc-cerium redox flow battery

摘要

Redox flow batteries (RFBs) can be used to store energy on the large and medium scale(kW – MW), particularly in applications such as load levelling of electrical powersupplies, power quality control application and facilitating renewable energy deployment.In this thesis, the development of a divided and undivided zinc-cerium redox flow batteryfrom its fundamental chemistry in aqueous methanesulfonic acid has been described. Thiscomprehensive investigation has focused on the selection of electrode materials,evaluation of zinc corrosion of the negative electrode, characterization of the redox flowbattery and the cycling performance. Voltammetric studies of both the zinc and the ceriumhalf-cell reactions have been carried out under various operating conditions and forelectrolyte compositions. These studies suggested that the positive electrode reactioncould limit the use of higher current densities. After testing a range of two- andthree-dimensional positive electrode materials, only three-dimensional platinised titaniummesh and carbon felts were capable of discharge at 50 mA cm-2 with high charge ( 70 %)and voltage ( 60 %) efficiencies in an divided system based on the optimum electrolytecompositions obtained in the half-cell studies. In order to avoid the diffusion of protonsacross the membrane and to simplify the construction, an undivided, membranelesssystem was proposed. With specific design arrangement and carbon felt positive electrode,this system can operate at room temperature with a high energy efficiency (~ 75 %)instead of 60 oC as reported in the patented system in the literature. In order to facilitatezinc electrodeposition and prevent zinc corrosion, several electrolytic additives andcorrosion inhibitors have been suggested. Further challenges and research directions arealso discussed.