The influence of morphology on proton transport in proton exchange membranes (PEM) is studied at the mesoscale using smoothed particle hydrodynamics (SPH), a mesh-free particle method for solving continuity equations. By solving the Nernst–Planck equation for proton transport in lamellar, cylinder, and cluster morphologies, we find that the proton conductivity for cluster morphology is much lower than lamellar and cylinder morphology at all hydration levels. This suggests the porosity and tortuosity in PEM morphology can reduce proton transport significantly at the mesoscale. We also investigated the effect of including a position-dependent diffusion constant (PDDC) tied to the local morphology, which is usually ignored in studies of proton transport in confinement. We calculated the PDDC in lamellar PEM using both quantitative and phenomenological approaches. SPH calculations show that conductivities for PEM systems with a PDDC can vary compared with systems with uniform diffusion constant. Therefore, it is potentially important to take into account the inhomogeneity of transport coefficients when studying proton transport in anisotropic systems.

Areas of Focus: Energy Markets
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Energy Markets
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Electric Power
As the electric power system faces new pressures and opportunities, EPIC research is working to identify the mix of policies needed to accelerate the global transition to clean, reliable, affordable...
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Energy Efficiency
Improving energy efficiency is lauded as a promising way reduce emissions and lower energy costs. Yet, a robust body of research demonstrates that not all efficiency investments deliver. EPIC faculty...
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Fossil Fuels
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Mobility is central to economic activity. Yet, a lack of fuel diversity and continued demand growth have made the transportation industry a major contributor to global pollution and carbon emissions....
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Renewable Energy
Lower technology costs and supportive public policies are driving an increase in renewable energy in markets around the world. EPIC research is assessing the costs, benefits, and efficiency of policies...
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Well-functioning markets are essential for providing access to reliable, affordable energy. EPIC research is uncovering the policies, prices and information needed to help energy markets work efficiently.