Using operando techniques to understand and design high performance and stable alkaline membrane fuel cells

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Alkaline membrane fuel cells (AMFCs) require optimized water management for high performance and durability.
• Understanding liquid water distribution is crucial for preventing performance loss and ensuring long-term stability.

Purpose of the Study:

• To visualize and understand the spatial and temporal distribution of liquid water within operating AMFCs.
• To identify operating conditions that lead to performance loss and to develop strategies for enhanced durability.

Main Methods:

• Operando neutron imaging.
• Operando micro X-ray computed tomography (micro-CT).

Main Results:

• Direct evidence of liquid water accumulation at the anode, causing ionomer swelling and performance degradation.
• Observation of cathode dryout due to insufficient water content.
• Identification that optimal power density conditions do not necessarily ensure long-term stable operation.

Conclusions:

• New catalyst layer and gas diffusion layer designs were developed based on water dynamics insights.
• Achieved continuous operation of AMFCs for over 1000 hours at 600 mA cm⁻² with a low voltage decay rate (32 μV h⁻¹).
• Demonstrated unprecedented durability for AMFCs, setting a new benchmark in the field.