Synergistic effect of ultrasonic and magnetic fields on the performance of non-aqueous iron-vanadium redox flow battery with deep eutectic solvent electrolyte

Abstract

In this paper, the synergistic effect of magnetic and ultrasonic fields on FeV redox flow battery with deep eutectic solvent (DES) electrolyte is studied. The results show that the synergistic effect of the two physical fields can reduce the high viscosity and increase diffusion coefficient of the DES electrolyte, and has a positive effect on the oxidation and reduction peaks of DES electrolyte of the FeV redox flow battery. Due to ultrasonic cavitation, the bursting of cavitation bubbles transfers energy to the DES electrolyte. The magnetic field changes the motion rate of charged particles through Lorentz force driving the charged particles in the electrolyte, and influences the electrochemical reaction rate. When the two physical fields are synergistically applied, ultrasonic plays a leading role, and the effect of the two physical fields acting together is better than that of either single physical field: The performance increment for the one with two fields affecting together is 37.1 %, which is larger than the sum of increments for applying a single field (for magnetic field, the increment is 8.6 %; for ultrasonic, 20.8 %). Besides, the application of magnetic field could reduce the cost of ultrasonic application, which is conducive to the application of ultrasonic technology in non-aqeous flow battery with DES electrolyte. In brief, this study shows that an effective and simple method improving the physical and electrochemical properties of DES electrolytes together with enhancing electrochemical reaction rate, which has the potential to be widely used in non-aqueous flow batteries.