The influence and control of ultrasonic on the transport and electrochemical properties of redox couple ions in deep eutectic solvent (DES) for redox flow battery application

The flow batteries with deep eutectic solvent (DES) electrolyte have the advantages of wide electrochemical window, low cost, and simple preparation of electrolyte. However, the drawbacks of high viscosity and low diffusion coefficient for ions in DES are the main factors hindering mass transfer in DES flow batteries. This paper reports the influence of adding ultrasonic on the transport and electrochemical properties of Fe(III)/Fe(II) redox couple in DES. Cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) are used to study the influence of different ultrasonic power densities and operating temperatures. The results show that the addition of ultrasonic has a remarkable positive effect on the physical and electrochemical properties of the DES electrolyte. At the same time, it has shown the necessarity to further study the application strategy of ultrasonic to reduce external energy consumption based on the timeliness of the ultrasonic effect.