context: Carbon surfaces often exhibit poor electrochemical characteristics and therefore need special pretreatment, frequently termed as “activation”. For surface sensitive redox couples the electron transfer at carbon electrodes may depend on edge plane exposure, surface functional groups and cleanliness. Porous electrode structures, such as carbon felts and carbon papers composed of randomly oriented CFs, also suffer from poor electrolyte accessibility, high pressure drops within the cell, and non-uniform electrolyte velocities. These issues limit the mass transport, for instance in redox flow cells, and thus their electrochemical performance. Some improvements have been achieved by modifying the cell architecture (by adding flow fields) and the electrode design. Another strategy is to employ electrodes that allow for control of the orientation of their fibres along the electrolyte flow.