Study On Electrolyte Of Zinc/Nickel Single Flow Battery

Redox flow batteries have excellent performance among the numerous large-scale energy storage technologies because of its flexible settings, rapid response and without geographical constraints. Zinc/nickel single flow batteries have been noticed widely which with the characteristics of low cost, long service life and membrane-free. Desiring to improve electrochemical performances, we study on electrolyte of single flow zinc/nickel battery by cyclic voltammetry, X ray diffraction, atomic emission spectrum etc.We first analyze the effects of current density, zinc deposition area capacity and electrolyte flow speed on the performance of zinc/nickel single flow batteries and zinc deposition morphology. The result show that the electrolyte flow speed should be matched with the zinc deposition area capacity. At low zinc deposition area capacity and low electrolyte flow speed, the spongy zinc deposition is relatively uniform and compact. While, at higher zinc deposition area capacity, clusters and particles turn into lager and their irregular is more serious. To improve the performance of zinc/nickel single flow battery, PbO or TEAH(tetraethyl ammonium hydroxide) the two electrolyte additives were used and the result was satisfactory. Besides, the mechanism of PbO and TEAH were investigated respectively. The result show that PbO go through codeposition mechanism to inhibit the growth of spongy zinc, while TEAH improves the performance of zinc/nickel single flow battery with sorption. The effects of electrolyte additives to sintered nickel was investigated. It is shown that PbO and TEAH have benefit to sintered nickel positive instead of adverse effects. The long-term performance of zinc/nickel single flow battery with electrolyte additive was turned to be stable.Because of sintered nickel high cost, we try to use low cost faure-type foam nickel electrode to instead. The powder of active substance sheds obviously, as a result, several processing methods were tested to inhibit this phenomenon. It is shown that coulombic efficiency and energy efficiency are increased and faure-type foam nickel electrode shows the potential of insteading sintered nickel electrode.