Fuel cells are a potential alternative energy source for many applications. The obvious one is automotive, and especially heavy transport over long distances. This specifically is an area in which EVs, their battery ranges and recharge times perform – for the time being – less than optimally. For fuel cell technology, ALD is all set to be utilized to gain an even bigger competitive edge.
Of different types of fuel cells, solid oxide fuel cells (SOFC) operate at high temperatures, typically at 600–1000 oC and they are based on ceramic electrolytes and electrodes, connected into stacks by metal interconnect plates. Typical electrolyte material is yttrium-stabilized zirconia (YSZ). ALD offers possibilities in depositing the electrolyte and electrode materials itself, as well as anti-corrosive protective layers on metal interconnects. Thin ALD layers can potentially enable lower resistance and faster reaction kinetics.
Polymer electrolyte membrane (PEM) fuel cells operate at 50–100 oC and electricity is generated at the so-called membrane electrode assembly in the core of the cell. Catalysts such as platinum are used at the electrodes to enable the electricity-generating chemical reactions. ALD offers a way to potential cost-savings as highly reactive, ALD-deposited nanoparticles or ‘atomic clusters’ of platinum (or other platinum group metals) can have the same catalytic efficiency as conventionally manufactured catalyst layers, but with much lower platinum loading.