An operando investigation of temperature distribution behaviour in full-cell vanadium-redox flow batteries

Abstract

This study analyzes the real-time temperature distribution patterns on the anode (negative electrode) and cathode (positive electrode) of the vanadium redox flow battery in a full-cell configuration. The patterns are analyzed under various current densities (60, 75, and 90 mA cm^–2), electrolyte flow rates (50 and 100 mL min^–1), and different operating temperatures of the cell and tanks (25 °C and 30 °C) during the galvanostatic cycling. The real-time temperature variations are recorded at the negative and positive electrodes during the charge-discharge cycling and then represented in 2D temperature distribution contours. It is noted that the temperature of the negative electrode increases during charging and falls during discharge. Conversely, the temperature of the positive electrode decreases during charging and increases during discharging. A comprehensive analysis and discussion of the temperature distribution at the electrodes are presented. Furthermore, the distribution of applied current density during the galvanostatic cycling at both electrodes is carefully mapped. The study offers valuable insights into the temperature distribution behavior of vanadium redox flow batteries, which could be advantageous for future technological advancements. Specifically, catholyte species precipitate during galvanostatic cycling at moderate temperatures, a problem for vanadium redox flow batteries.