Hydrogen fuel cells are systems that exploit the electrochemical reaction of hydrogen (H2) and oxygen to produce electricity. As long as a fuel cell has a constant input of hydrogen and oxygen they can continue to produce electricity.
Hydrogen fuel cells first found commercial applications for the generation of power in NASA space vehicles such as space capsules and satellites. Since then, fuel cells have been employed in a wide range of different scenarios including for portable and stationary backup power, for transportation, and for material processing.
When compared to conventional technologies, which are driven by fossil fuel consumption, hydrogen fuel cells offer a number of big advantages – the biggest being they only emit water, with zero carbon dioxide emission.
How Hydrogen Fuel Cells Work
Proton Exchange Membrane (PEM) hydrogen fuel cells function via reverse electrolysis. The fuel cell has two electrodes – one positive (the cathode) and another negative (the anode) which have an electrolyte and a membrane between them.
Oxygen is introduced to the cathode, and hydrogen to the anode, which is embedded with a catalyst. The catalyst-embedded anode splits hydrogen into electrons and protons. The electrons flow through the circuit, generating electricity, whereas the protons migrate through the PEM and electrolyte to the cathode where they react with oxygen to produce heat and water.
Fuel Cell Types
Whilst there are many different varieties of fuel cells the most common types can be categorized as alkaline, solid oxide, PEM, molten carbonate or phosphoric acid.
This categorization is based on what type of electrolyte the fuel cell possesses, and this also determines if the hydrogen must be purified during processing and also the operational temperature of the fuel cell.
Acquiring Hydrogen to Test Fuel Cells
When developing fuel cells a reliable and clean source of hydrogen is required for fuel cell testing.
Gas cylinders of hydrogen, bought from a supplier, are one potential option though these present safety hazards and can be cumbersome to work with. In addition, the cylinders must be stored, which takes up space, and constantly replenished to ensure there is no research downtime.
A better option is the use of on-site gas generation. On-site methods can provide ultra-pure hydrogen gas as and when it is required, without the safety concerns and the need for storage associated with gas delivery. All that is needed to produce hydrogen gas on site is the generation system, electricity, and water.
This information has been sourced, reviewed and adapted from materials provided by Nel Hydrogen.
For more information on this source, please visit Nel Hydrogen.