In situ compression and X-ray computed tomography of flow battery electrodes

Rhodri Jervis , Matt D.R. Kok , Tobias P. Neville , Quentin Meyer , Leon D. Brown , Francesco Iacoviello , Jeff T. Gostick , Dan J.L. Brett , Paul R. Shearing - Electrochemical Innovation Lab, Department of Chemical Engineering, University College London,Department of Chemical Engineering, McGill University, Montreal, Porous Media Engineering and Analysis Lab, Department of Chemical Engineering, University of Waterloo, Canada

Redox flow batteries offer a potential solution to an increase in renewable energy generation on the grid by offering long-term, large-scale storage and regulation of power. However, they are currently underutilised due to cost and performance issues, many of which are linked to the microstructure of the porous carbon electrodes used. Here, for the first time, we offer a detailed study of the in situ effects of compression on a commercially available carbon felt electrode. Visualisation of electrode structure using X-ray computed tomography shows the non-linear way that these materials compress and various metrics are used to elucidate the changes in porosity, pore size distribution and tortuosity factor under compressions from 0%–90%.

How Amira-Avizo Software is used

Avizo software was used to visualise the data and to segment the greyscale images into binary data sets where pixels are assigned to the fibre and pore phase through a thresholding procedure coupled with the removal of isolated islands of noise, such that only the fibre structures (which are contiguous across many hundreds of voxels in three
dimensions) remain selected.