Speaker
Description
Anion exchange membrane water electrolysis is a promising technology for cost-effective green hydrogen production. However, its performance is strictly constrained by the coupled multiphase mass transport and reaction kinetics within the porous transport electrode. Specifically, the rapid accumulation of bubbles within the porous network often impedes electrolyte replenishment, leading to severe mass transport overpotentials. To resolve the structure-performance trade-offs, this study presents a multiscale framework combining pore-scale Lattice Boltzmann Method (LBM) simulations with experimental characterization.
We systematically investigated the impacts of pore size (5–80 µm) and electrode thickness (0.5–2.0 mm) on cell performance. Micro-scale LBM simulations, utilizing Gaussian Random Field reconstruction to capture stochastic geometries, revealed a critical trade-off. The simulation results, validated by electrochemical measurements, indicate that while large pores facilitate mass transport by exponentially enhancing permeability and reducing tortuosity, they lead to a significant reduction in specific surface area and a two-fold increase in contact resistance. Conversely, increasing electrode thickness theoretically enhances electrochemical active surface area but is limited by mass transport. The effective reaction zone analysis indicates that the utilization rate of electrochemical active surface area in thick electrodes (2.0 mm) is strictly limited to less than 40% by deep-pore bubble accumulation and high pressure drop. To quantify these competing mechanisms, a performance loss index was proposed. This model decouples the overpotential contributions and identifies the optimal geometric architecture that balances active area and transport resistance. In summary, these findings provide quantitative guidelines for the rational design of porous electrodes to minimize ohmic and transport losses, enabling high-efficiency anion exchange membrane water electrolysis operation.
| Country | China |
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