A Persistent Barrier to Hydrogen Fuel Adoption
The UNSW Solution: Lateral Bypass Flow Fields
Significance of the Research
Potential Impact Across Industries
What’s Next?
References and Further Reading
As the global transition toward low-carbon energy accelerates, hydrogen fuel cells are gaining renewed attention for their potential to decarbonize sectors where conventional electrification remains challenging. A recent breakthrough by UNSW researchers addresses a long-standing engineering limitation, bringing the technology closer to practical, cost-effective commercial deployment.
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A Persistent Barrier to Hydrogen Fuel Adoption
For decades, hydrogen fuel cells have been regarded as one of the most promising clean energy technologies because they convert hydrogen directly into electricity with water as the only byproduct. They also offer sustained power output, high efficiency, rapid refueling capability, and continuous operation under stable fuel supply conditions. This makes them an attractive option for applications ranging from transportation to stationary power generation.
Despite these advantages, large-scale deployment has been constrained by high cost and persistent engineering limitations.
Within the fuel cell system, water generated during operation accumulates and becomes trapped in the porous electrode structure. This restricts oxygen transport and reduces electrochemical performance.
Conventional mitigation approaches, such as increased backpressure or higher platinum loading, partially alleviate flooding but introduce penalties in system efficiency, cost, and weight.
As a result, there is a need for more efficient, low-cost system-level solutions that address the underlying limitations without added energy, cost, or weight penalties.1,2 In the UNSW study, this limitation was evaluated under hydrogen-air operation at ambient pressure and at high current densities above 1 A cm-², making the reported improvement especially relevant to practical operating conditions.1,3
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The UNSW Solution: Lateral Bypass Flow Fields
UNSW researchers recently introduced a redesigned fuel cell architecture that addresses water accumulation at its source rather than relying on downstream compensatory strategies.
The approach modifies a conventional serpentine flow field by incorporating 100 μm lateral bypass channels into the rib regions. These features are fabricated using high-precision computer-numerically-controlled micro-milling, enabling controlled geometric integration at the microscale.
The lateral bypass channels are positioned between adjacent flow channels across the rib structure and are dimensioned to correspond closely with the pore scale of the gas diffusion layer. This configuration creates transverse pathways that connect neighboring channels, providing additional routes for liquid water transport.
During operation, accumulated water beneath the rib region is redirected into the lateral bypass channels by capillary forces, then transported into adjacent channels for removal by the gas flow.
This redistribution mechanism modifies the fuel cell's internal fluid dynamics, improving phase transport balance and reducing localized saturation within the electrode structure.1,3
According to the paper, the design suppresses water concentration losses by up to 97%, indicating that the geometric change is structural and directly tied to improved mass-transport behavior within the cell.1 The study also supported this mechanism using operando electrochemical impedance spectroscopy, operando neutron imaging, computational fluid dynamics, and analytical modeling, which strengthens the case that the observed gains reflect real transport improvements rather than a single-test effect.1
Significance of the Research
These modifications led to a notable performance gain in hydrogen fuel cell operation, with reported peak power density increases of up to 75% at low platinum loading (0.2 mgPt cm-²) under ambient pressure. Therefore, high-performance operation can be achieved without relying on expensive catalysts such as platinum or high-pressure systems, reducing a key cost barrier in hydrogen fuel cell deployment.
The design also enhances durability by mitigating localized flooding and ensuring more uniform water distribution throughout the electrode structure. This reduces concentration gradients, mechanical stress, and catalyst-degradation mechanisms, such as particle detachment and carbon-support corrosion, which are typically accelerated under uneven mass-transport conditions.
As a result, the fuel cell maintains more stable operating conditions during sustained high-current operation, supporting longer service life and improved operational reliability in practical applications.1,3
The paper reports absolute peak power densities of 0.63, 0.76, and 1.1 W cm-² for different cathode catalyst loadings, providing important quantitative context for the percentage improvement cited above.1
The researchers also reported strong performance across PtCo, Pt, and platinum-free catalyst systems, suggesting that the benefits of the lateral bypass design may extend beyond a single catalyst configuration.1
While improved water management could support more stable long-term operation, the strongest result demonstrated in the study is improved flood resistance and electrochemical performance under demanding operating conditions.1,3
Potential Impact Across Industries
The persistent global fuel crisis has highlighted the need for such clean energy solutions, particularly in sectors where electrification is constrained by low energy density, high weight penalties, and limited operational endurance.
In aviation, hydrogen fuel cells will enable longer-range regional flight due to higher specific energy, while reduced system mass will improve propulsion efficiency and extend operational range.
In heavy freight transport, the improved design will reduce limitations associated with battery weight and long charging times by improving low-pressure efficiency and lowering catalyst requirements, supporting sustained long-haul operation.
Maritime, off-grid, and stationary power systems will similarly benefit from improved power-to-weight ratios, simplified system architecture, and enhanced reliability, addressing key constraints in deployment, maintenance, and continuous operation in remote or demanding environments.4
These sector-wide implications remain forward-looking, but the UNSW team has specifically identified low-altitude aviation as an initial application area for early validation and deployment.3
What’s Next?
Dr. Meyer and Prof. Zhao have already patented the technology, and ongoing efforts are focused on scaling the design for commercial deployment. The team is planning to introduce the technology for low-altitude aviation as an initial application area for near-term implementation and validation, providing a pathway for early-stage operational testing under real-world conditions.
Such advancements will strengthen the role of hydrogen as a complementary clean energy carrier for sectors that are difficult to electrify, supporting long-term decarbonization objectives and contributing to emission reduction pathways aligned with global climate targets, including the Paris Agreement.3
References and Further Reading
- Meyer, Q., Wang, Y. D., Niblett, D., Bin Mamtaz, M. R., Akbar, M., Nie, Y., Liu, S., Lee, J., Boillat, P., Tang, K., Tung, P., Mostaghimi, P., Armstrong, R. T., & Zhao, C. (2026). Lateral bypass flow fields for high-performance flood-free hydrogen fuel cells. Applied Catalysis B: Environment and Energy, 393, 126713. https://doi.org/10.1016/j.apcatb.2026.126713
- Cai, C., Rao, Y., Zhang, Y., Wu, F., Li, S., & Pan, M. (2019). Failure mechanism of PEM fuel cell under high back pressures operation. International Journal of Hydrogen Energy, 44(26), 13786-13793. https://doi.org/10.1016/j.ijhydene.2019.03.221
- Melville, T. (2026). New hydrogen fuel cell design could unlock key clean energy technology. https://www.unsw.edu.au/newsroom/news/2026/04/new-hydrogen-fuel-cell-design-could-unlock-key-clean-energy-technology
- A. Qasem, N. A., & Q. Abdulrahman, G. A. (2023). A Recent Comprehensive Review of Fuel Cells: History, Types, and Applications. International Journal of Energy Research, 2024(1), 7271748. https://doi.org/10.1155/2024/7271748
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