The effect of wetting area in carbon paper electrode on the performance of vanadium redox flow batteries: A three-dimensional lattice Boltzmann study

Duo Zhang, Qiong Cai, Oluwadamilola O.Taiwo, Vladimir Yufit, Nigel P.Brandon, Sai Gu - Department of Chemical and Process Engineering, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH, United Kingdom; Department of Earth Science & Engineering, Faculty of Engineering, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom.

The vanadium redox flow battery (VRFB) has emerged as a promising technology for large-scale storage of intermittent power generated from renewable energy sources due to its advantages such as scalability, high energy efficiency and low cost. In the current study, a three-dimensional(3D) Lattice Boltzmann model is developed to simulate the transport mechanisms of electrolyte flow, species and charge in the vanadium redox flow battery at the micro pore scale. An electrochemical model using the Butler-Volmer equation is used to provide species and charge coupling at the surface of active electrode. The detailed structure of the carbon paper electrode is obtained using X-ray Computed Tomography(CT). The new model developed in the paper is able to predict the local concentration of different species, overpotential and current density profiles under charge/discharge conditions. (…) It is found that the electrochemical performance of positive half cell is reduced with air bubbles trapped inside the electrode.

How Amira-Avizo Software is used

Image pre-processing and segmentation of the resulting reconstructed volume was carried out using commercial image processing software (Avizo v9.3). In here, a Gaussian smoothing filter was applied to the reconstructed volume to reduce the image noise. Threshold-based segmentation of the volume was then performed to isolate the carbon fibres from the pore/electrolyte phase.