Waterloo's Diamond Electrodes Could Make Grid Storage Cheaper and Safer

A team at the University of Waterloo has used 3D printing to make porous carbon electrodes for redox flow batteries, the large-scale storage systems that utilities rely on to hold wind and solar energy. By changing the internal geometry of the electrodes, the researchers improved battery performance by more than half.

Redox flow batteries work differently from the lithium-ion packs in phones and electric vehicles. They store energy in liquid electrolytes kept in external tanks, which makes them safer for grid-scale use because the liquids are water-based rather than flammable. The catch has always been efficiency. Getting the electrolyte to contact enough surface area inside the battery determines how much power the system can deliver.

Professor Maxime van der Heijden and his group turned to 3D printing to solve that. They printed porous structures using a digital light-processing printer, then heat-treated them into conductive carbon electrodes. The key was the shape inside. They tested several triply periodic minimal surface geometries, complex repeating patterns found in nature, and found that a diamond lattice outperformed the rest by 52%.

That improvement comes from better fluid flow. The diamond geometry channels the electrolyte through the electrode more evenly, so more surface area participates in the chemical reactions that store and release energy. The result is a battery that can charge and discharge more efficiently without needing exotic materials or bigger tanks.

The team validated the design in both lab flow cells and a working vanadium redox flow battery. The proof of concept opens the door to scaling the approach. Future work will focus on increasing the electrode surface area further and making the manufacturing process faster and cheaper.

Grid storage is becoming critical as more wind and solar farms come online. Unlike coal or gas plants, renewables do not always produce when demand peaks. Better flow batteries mean less wasted clean energy and fewer lithium-ion megapack fires.