Papers by Keyword: Redox Flow Battery

Abstract: Efficient bipolar plates are needed to store electricity from renewable energies. Here the focus is concentrating on graphite-compound-Bipolar plates, which are one of the most used components in a Fuel Cell Stack system. Among other things, polypropylene is a suitable matrix material, but other polymer materials such as PPS and PVDF and phenolic resins can also be considered. However, for a correspondingly high conductivity in the fuel cell system, the plastic must be filled with up to more than 80 % graphite. To ensure that the compound is not brittle afterwards and is as easy to process as possible, an impact modify cation was further developed that makes it possible to produce thin films.

Abstract: A Cd-Fe redox flow battery is proposed, in which CdSO₄-H₂SO₄ aqueous solution is used as negative electrolyte, FeSO₄-Fe₂(SO₄)₃-H₂SO₄ aqueous solution is used as positive electrolyte, copper is used as negative electrode, carbon felt is used as positive electrode and proton exchange membrane is used as separator. Fe²⁺ is oxidized to Fe³⁺ at positive electrode and the Cd²⁺ is reduced to cadmium and electroplated onto the negative electrode during charge. The reverse occurs during discharge. An average discharge cell voltage of about 0.99V at 10mA/cm² and an average energy efficiency of about 70.8% are obtained.

Abstract: The effect of sulfosalicylic acid (SSA) on the electrochemical behaviour of Ce³⁺/Ce⁴⁺ redox couple was studied using voltammetry at stationary electrode and rotating disc electrode (RDE). When the SSA was added to the Ce³⁺/Ce⁴⁺ electrolyte there was change to the peak current and peak potential, i.e. the increase of peak current and the decrease of peak potential difference. The diffusion coefficient of Ce³⁺ is 6.5 × 10^-6 cm² s^-1 and the standard rate constant of the Ce³⁺/Ce⁴⁺ redox reaction is 3.2 × 10^-4 cm s^-1 in the presence of SSA, which are all larger than that in the absence of SSA (3.6 × 10^-6 cm² s^-1, 2.0 × 10^-4 cm s^-1). Therefore, the SSA as the additive in the supporting electrolyte for a cerium redox flow battery (RFB) application will result in a high voltage efficiency and will satisfy an important requirement for a RFB electrolyte.

Abstract: The electrochemical behavior of Nitroso-R-salt (NRS) in aqueous solutions and the influence of pH are investigated. In alkaline solution, the electrode reaction of NRS exhibits stagnant electrode kinetics. With rising acid concentration, it exhibits more and more fast electrode kinetics and a diffusion-controlled process. Thus, acidic aqueous solutions are favorable for the NRS as active species of a redox flow battery (RFB). Average coulombic and energy efficiencies of the NRS/Zn RFB are 93.2 and 80.6%, respectively, showing that self-discharge is small. The preliminary exploration shows that the NRS is electrochemically promising for RFB application.