'Blood battery' announced for the first time in the world

Scientists at the University of Cordoba in Spain have developed a way to incorporate hemoglobin - the main component of red blood cells - into a battery, creating a battery that can operate for about 20 to 30 days.

Zinc-air batteries are one of the most sustainable alternatives to the popular lithium-ion batteries that power many devices today, from laptops to electric cars. They work through a chemical reaction called the oxygen reduction reaction. When air is drawn into the battery, oxygen is reduced to water at the cathode (anode), releasing zinc oxidizing electrodes at the anode (negative electrode).

To sustain this reaction, you need a good catalyst, with some very specific properties. The researchers realized that hemoglobin certainly could do the trick. 'To be a good catalyst in the oxygen reduction reaction, a catalyst must have two properties: it needs to absorb oxygen molecules quickly and form water molecules relatively easily,' explains senior author Manuel Cano Luna. 'And hemoglobin meets those requirements.'

Hemoglobin is the protein that gives red blood cells their characteristic color and their ability to carry oxygen. It is fundamental to how our bodies function, and it is also present in batteries: just 0.165 milligrams of hemoglobin can keep a battery running for 20-30 days.

Using a biological catalyst like this could be key if these batteries are to be used in devices implanted inside the body, such as pacemakers, the researchers say. The battery operates at a pH of 7.4, which is very similar to the pH of blood.

There are still some things to work on, however. The biggest problem right now is that these batteries aren't rechargeable , so the team is looking for a protein that can turn water back into oxygen and start the reaction cycle over again, meaning these batteries won't be usable for space applications.

Energy storage remains a major obstacle in humanity's journey to a more sustainable future, so batteries are always improving. While lithium-ion batteries are a big part of solving this problem, the issues surrounding mining enough lithium and the waste it creates are still among the options.