A team of University of Toronto chemists has created a battery that stores energy in a biologically derived unit, paving the way for cheaper consumer electronics that are easier on the environment.
The battery is similar to many commercially-available high-energy lithium-ion batteries with one important difference.
It uses flavin from vitamin B2 as the cathode: the part that stores the electricity that is released when connected to a device.
Modern batteries contain three basic parts:
- a positive terminal – the metal part that touches devices to power them – connected to a cathode inside the battery casing
- a negative terminal connected to an anode inside the battery casing
- an electrolyte solution, in which ions can travel between the cathode and anode electrodes
When a battery is connected to a phone, iPod, camera or other device that requires power, electrons flow from the anode out to the device, then into the cathode and ions migrate through the electrolyte solution to balance the charge.
When connected to a charger, this process happens in reverse.
The reaction in the anode creates electrons and the reaction in the cathode absorbs them when discharging. The net product is electricity.
The battery will continue to produce electricity until one or both of the electrodes run out of the substance necessary for the reactions to occur.
While bio-derived battery parts have been created previously, this is the first one that uses bio-derived polymers for one of the electrodes.
It allows battery energy to be stored in a vitamin-created plastic, instead of costlier, harder to process, and more environmentally-harmful metals such as cobalt.
Schon, Seferos and colleagues happened upon the material while testing a variety of long-chain polymers – specifically pendant group polymers: the molecules attached to a ‘backbone’ chain of a long molecule.
The team created the material from vitamin B2 that originates in genetically-modified fungi using a semi-synthetic process to prepare the polymer by linking two flavin units to a long-chain molecule backbone.
This allows for a green battery with high capacity and high voltage – something increasingly important as the ‘Internet of Things’ continues to link us together more and more through our battery-powered portable devices.
B2’s ability to be reduced and oxidized makes its well-suited for a lithium ion battery.
While the current prototype is on the scale of a hearing aid battery, the team hopes their breakthrough could lay the groundwork for powerful, thin, flexible, and even transparent metal-free batteries that could support the next wave of consumer electronics.
The team’s paper outlining the discovery is published in the journal Advanced Functional Materials.
Citation: Schon TB et al. (2016). Bio-Derived Polymers for Sustainable Lithium-Ion Batteries, Advanced Functional Materials, published online. DOI: 10.1002/adfm.201602114.
Figure legend: This Knowridge.com image is credited to Diana Tyszko/ University of Toronto.