Japanese researchers find caffeine boosts fuel cell efficiency

In Japan, fuel cells, while promising, are expensive due to high catalyst requirements to increase the oxygen reduction reaction (ORR) activity. In a breakthrough, researchers found that adding caffeine to the electrodes can improve the ORR activity of platinum electrodes 11 times. This discovery can enhance the efficiency of the fuel cell, reduce the requirement for excess platinum catalysts, and ultimately lead to cheaper and more efficient fuel cells.

With global goals set on transitioning away from fossil fuels, fuel cells stand out as a promising carbon-free energy source. Comprising an anode and a cathode separated by an electrolyte, fuel cells convert the chemical energy of fuel directly into electricity. The anode receives the fuel, while an oxidant, typically oxygen from the air, is introduced at the cathode. In a hydrogen fuel cell, hydrogen undergoes oxidation at the anode, producing hydrogen ions and electrons. The ions move through the electrolyte to the cathode, and electrons flow through an external circuit, generating electricity. At the cathode, oxygen combines with the hydrogen ions and electrons, resulting in water as the sole byproduct.

However, the presence of water affects the performance of the fuel cell. It reacts with the platinum (Pt) catalyst, forming a layer of platinum hydroxide (PtOH) on the electrode, which obstructs the efficient catalysis of the oxygen reduction reaction (ORR), leading to energy losses. To maintain efficient operation, fuel cells require a high Pt loading, which significantly increases the costs of fuel cells.  

Now, in a study published in the journal Communications Chemistry on February 3, 2024, researchers from the Graduate School of Engineering at Chiba University, Japan, have found that adding caffeine to certain platinum electrodes can increase the activity of the ORR. This discovery has the potential to reduce platinum requirements, making fuel cells more affordable and efficient.