Formic acid fuel cell

Formic acid fuel cells (direct formic acid fuel cells or DFAFCs) are a subcategory of direct liquid-feed fuel cells (DLFCs), in which the liquid fuel is directly oxidized (electrochemically) at the anode instead of reforming to produce hydrogen. Formic acid-based fuel cells represent a promising energy supply system in terms of high volumetric energy density, theoretical energy efficiency, and theoretical open-circuit voltage. They are also able to overcome certain problems inherent to traditional hydrogen (H₂) feed fuel cells such as safe handling, storage, and H₂ transportation.

There are 3 main types of DFAFCs:

Active DFAFCs, where a pump feeds the liquid fuel into the anode and oxygen in compressed air to the cathode.
Active air-breathing DFAFCs, where the cathode is exposed to the oxygen present in ambient air.
Passive air-breathing DFAFCs, where there are no mechanical components injecting fuels and oxygen into the cell.

The feeding of fuels and air into a cell increases its energy output, at the cost of price and size/portability.^[1]

Today, the main applications of DFAFCs include small, portable electronics, medical diagnostic devices, as well as larger fixed power applications and electric vehicles.

^ Ma, Zhenni; Legrand, Ulrich; Pahija, Ergys; Tavares, Jason R.; Boffito, Daria C. (2021-01-20). "From CO 2 to Formic Acid Fuel Cells". Industrial & Engineering Chemistry Research. 60 (2): 803–815. doi:10.1021/acs.iecr.0c04711. ISSN 0888-5885. S2CID 230551252.

[Ma_803–815-1] Ma, Zhenni; Legrand, Ulrich; Pahija, Ergys; Tavares, Jason R.; Boffito, Daria C. (2021-01-20). "From CO 2 to Formic Acid Fuel Cells". Industrial & Engineering Chemistry Research. 60 (2): 803–815. doi:10.1021/acs.iecr.0c04711. ISSN 0888-5885. S2CID 230551252.

[1]