​The quality of the hydrogen injected into fuel cells directly influences fuel cell performance. However, regardless of how hydrogen is produced (by water electrolysis or cracking biomass or natural gas), providing a guarantee of its purity costs money. Liten, a CEA Tech institute, completed a series of tests to measure the influence of several impurities on fuel cells in order to determine the optimal compromise between cost and performance.

The pollutants studied (NH3, HCl, and C4Cl4F6) were voluntarily introduced separately and in tiny amounts into pure hydrogen. The performance of fuel cells using the "polluted" hydrogen was tested on equipment developed and validated for this purpose. For example, appropriate measures were taken to prevent the test benches' piping from adsorbing substances so as not to skew the results. The impact of the pollutants on fuel cell lifespans was measured by extrapolating the results obtained from 900 hours of testing. The membrane electrode assemblies were autopsied so that the impact of the various pollutants on the degradation of the materials could be studied.

The results obtained were used to make recommendations on the acceptable amounts of each pollutant studied, and will serve as baselines for future versions of hydrogen quality standards, which will be drawn up with input from international hydrogen stakeholders (hydrogen producers, filling stations, automotive manufacturers).