Batteries bolstered by taking their B2 vitamins

Amid mounting expectations that we will be using ever more sophisticated batteries to power everything from portable electronics to our vehicles and homes, scientists are taking a fresh look at what kinds of materials will have to go into the electrodes of these devices. The usual candidates include an array of metals, some more exotic than others, but a team at the University of Toronto is moving in an entirely different direction, studying possible organic components.

Specifically, the team has developed a cathode made of a biolog- ically derived polymer that is based on a flavin vitamin B2. In a paper for Advanced Functional Materials published this past July, the group describes how this material was incorporated into the platform of a standard coin-cell lithium-ion battery. Although the unusual molecular geometry of the flavin affected charging and discharging behaviour, the resulting storage capacity and operating potential matched that of existing commercial offerings. In addi- tion, U of T chemistry professor and Canada Research Chair in Polymer Nanotechnology Dwight Seferos insists that the impact of this innovation goes beyond its purely technical performance. “We see this as a disruptive technology that will allow for batteries that are radically different from the ones that are available today,” Seferos says. “For example, flexible thin-film batteries, transparent batteries — all the things that polymers can do that metals can’t.” PhD student Tyler Schon, who is lead author of the paper, says that the small organic molecules could become the foundation of a much more efficient class of batteries. The polymer gives it a processing advantage while the reversible redox chemistry of vitamin B2 — which can accept two electrons per unit — made it an attractive place to start. Similar compounds are waiting in the wings, says Schon, who would eventually like to build a library of them for battery-makers.

Seferos adds that the ability to use sustainable, renewable organic constituents would free battery manufacturers from the vagaries of supply lines for metals such as cobalt, most of which comes from a politically unstable part of Africa and may not even exist in sufficient quantities to meet global demand as battery use grows.