Researchers at the University of Córdoba in Spain have developed a rechargeable zinc-air battery using vitamin B12 as a catalyst, demonstrating a new application for the vitamin in energy storage. The prototype has completed up to 250 charge-discharge cycles, marking an advance in the search for safer and more sustainable alternatives to conventional lithium-ion batteries.
The battery was developed by the Physical Chemistry research group (FQM-204) at the university's Chemical Institute for Energy and the Environment (IQUEMA). The team used vitamin B12, also known as cobalamin, anchored to single-walled carbon nanotubes. The vitamin contains cobalt (III) at its core, which helps facilitate the electrochemical reactions required for battery operation.
The researchers faced the challenge of preventing vitamin B12 from dissolving in the battery's aqueous electrolyte because of its high solubility in water. They addressed this by attaching the vitamin to carbon nanotubes, replicating "the process by which amino acids bind together in proteins", explained Manuel Cano Luna, the study's lead author.
The group had previously explored biomolecules as catalysts in batteries using haemoglobin and catalase, which contain iron (II) and iron (III), respectively. However, the latest prototype is the first of the team's biomolecule-based batteries to achieve rechargeability.
Vitamin B12 helps the battery function during both charging and discharging. It helps convert oxygen into water when the battery is in use and releases oxygen when it is being recharged. "Vitamin B12 has proven to meet the necessary conditions to act as a good catalyst," said researcher Antonio Jesús Fernández Romero.
Zinc-air batteries use abundant, recyclable zinc and oxygen from the surrounding environment, making them lighter than batteries that must store all their reactive materials internally. Their non-flammable aqueous electrolytes also offer improved safety. The researchers say the development could contribute to cheaper energy storage systems, including batteries for storing surplus electricity generated from renewable sources.