Abstract
Vanadium-manganese flow battery is a promising renewable energy storage system due to higher energy density as well as lower cost of Mn(II)/Mn(III) redox couple in the cathode than V(II)/V(III). The non-isothermal 2-D model describing the thermo-electrochemical behaviors in the main reactions of V(II)/V(III) and Mn(II)/Mn (III) along with the side reaction of Mn(II)/MnO2 is established to investigate the energy loss including power consumption and Joule heating loss associated with parameter researches, and the simulations agree with the experimental data. The amount of MnO2 precipitation in the side reaction is inverse proportional to the discharge current density and electrode porosity. While the temperature rises from T = 5 to 45 ?, more power consumption deriving from deposition reaction than dissolution reaction occurs in the discharge, and the Joule heating loss acts as a main factor to influence energy loss as well as it increases with the rise of current density at lower temperatures. The maximum energy density of 32.17Wh/L and voltage efficiency of 93.07% arise respectively with electrode porosities of epsilon = 0.8 and epsilon = 0.7 under the current density of i = 50 mA/cm(2), and the larger voltage efficiency and less power consumption accounting for total energy loss can be obtained with the electrode porosity of epsilon = 0.8, thus, the better performances can be obtained in the vanadium-manganese flow battery with optimized electrode porosity under the applicable operating conditions proposed in this work.
NSTL
Elsevier