The impacts of membrane pinholes on PEM water electrolysis.

Polymer electrolyte membrane (PEM) water electrolysis is a promising technology to efficiently produce green hydrogen. Irregularities in membrane electrode assembly (MEA) component materials caused by manufacturing, processing, handling, or operation can lead to performance loss and failure. One example is the presence of pinholes in the membrane, which can cause increased gas transport (crossover) and lead to electrical shorting. This work investigates the effects of intentionally introduced pinholes with various sizes up to 350 μm in diameter. The presence of the pinholes resulted in minimal impacts on the cell voltage (±30 mV at 4 A cm−2). However, the pinholes significantly increased H 2 crossover, which decreased hydrogen production efficiency and increased the minimum current density for safe operation. The impacts of the pinhole on the H 2 crossover and efficiency are more severe for open pinhole features than tear-like pinhole features. This research demonstrates that even small pinholes cannot be disregarded from a safety, efficiency, and operating strategy perspective. • Pinholes impact PEM electrolyzer H 2 crossover, efficiency, and safety. • Pinholes have minimal impact on V–I curves. • Open-shaped pinholes increase hydrogen crossover dramatically more than tear-like pinholes. [ABSTRACT FROM AUTHOR]