The UCO develops a rechargeable battery that runs on vitamin B-12

University of Córdoba

Vitamin B12 is a vitamin essential for the body's proper functioning and is found in foods of animal origin. It is produced by certain bacteria that, in addition to being found in nature, are cultivated at industrial facilities for commercial use, primarily by the food and pharmaceutical industries. It is beneficial when certain nutritional deficiencies are present, and in recent times it has become popular, along with other B vitamins, as a remedy for hangovers, as it can help reduce fatigue. An unusual application may now be added to its established uses in medicine, food, and veterinary science: a team from the University of Córdoba has, for the first time, employed it as a catalyst in the development of a rechargeable battery.

The prototype was designed by researchers with the Physical Chemistry research group (FQM-204) at the Chemical Institute for Energy and the Environment (IQUEMA) of the University of Córdoba. It consists of a zinc-air battery that incorporates vitamin B12, also known as cobalamin, which is anchored to single-walled carbon nanotubes. This configuration facilitates the electrochemical reaction because the vitamin contains cobalt (III) at its core. This is the third time that this group has used a biomolecule as a catalyst, following their previous work on batteries made with haemoglobin and catalase, which contain iron (II) and iron (III), respectively. The major breakthrough is that, in the case of B12, the team has succeeded in making the battery they developed rechargeable, achieving up to 250 charge and discharge cycles.

When selecting the material, "we looked at the properties we can find in naturally occurring materials to use them in new batteries," explained Manuel Cano Luna, author of the study, along with researchers Valentín García Caballero, Miguel López León, Pablo Gómez Argudo, Luis Camacho Delgado, José Miguel Rodríguez Mellado, María Teresa Martín Romero, José Abad López, and Antonio Jesús Fernández Romero. Because it is a highly soluble vitamin, the challenge was to find a way to retain it inside a battery that operates with aqueous electrolytes. The solution was to fix it to carbon nanotubes, simulating "the process by which amino acids bind together in proteins".

Light weight, safe, and sustainable

The study, published in the Journal of Materials Chemistry A, marks another step forward in the search for alternatives to conventional lithium-ion batteries, which rely on raw materials whose extraction poses economic, social, and environmental challenges. In this regard, zinc-air batteries are a promising alternative due to their high energy density and their use of materials such as zinc – which is abundant and recyclable – and oxygen itself. In addition, as they do not need to store all the reactive material inside the battery because they get oxygen from the environment, these batteries are lighter, which is why their use is becoming increasingly widespread in small devices, such as hearing aids. The use of non-flammable aqueous electrolytes also makes them safer.

However, to facilitate the reaction that converts chemical energy into electrical energy, an effective catalyst is needed; in the case of rechargeable batteries, this catalyst must also be capable of performing its function in both directions: charging and discharging. In this case, researcher Antonio Jesús Fernández Romero explained that vitamin B12 "has proven to meet the necessary conditions to act as a good catalyst because, during discharge, it catalyses the reduction of oxygen to water and, during recharging, it promotes the production of oxygen".

This breakthrough paves the way for the development of cheaper and more sustainable energy storage systems that could play key roles in addressing some of the challenges posed by the energy transition, such as creating batteries capable of storing the surplus energy generated by renewable sources.