Fig. 4: MEA water evolution, calculation of the current and potential-dependent water formation and time to reach the water volume equilibrium. | Nature Communications

Fig. 4: MEA water evolution, calculation of the current and potential-dependent water formation and time to reach the water volume equilibrium.

From: High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells

Fig. 4: MEA water evolution, calculation of the current and potential-dependent water formation and time to reach the water volume equilibrium.

a and b The volume increase of the water generated inside the MEA for constant current density and potential, respectively. Higher currents/ lower potentials cause a faster water uptake, which saturates for higher operational cell power. c and d Determine the maximal water volumes in the MEA. To use the same saturation function the potential values in d are reversed with a maximal open circuit potential of 1.0 V. e and f Evaluates the time needed to reach the water equilibrium for given current and potential densities of 95 % and 99 % of equilibrium, with corresponding fit functions for e. A fit for f is not possible due to the large uncertainties and small number of measurements.

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