Renewable energy solutions could change the way we store solar and wind.

An environmentally friendly and safer alternative to lithium-ion batteries, redox-flow batteries are used for grid storage, but they are big —usually the size of a shipping container—slow and expensive.

New research by Te Whare Wānanga o Waitaha | University of Canterbury PhD candidate Sophie McArdle aims to increase performance while reducing the size and the overall cost of producing redox-flow batteries.

With decreasing costs of renewable energies, there are global economic drivers to store these energies within countries with large amounts of solar and wind.

“The success of redox-flow batteries will mean cheaper energy, energy security, and provide alternatives for off grid applications not only by nations, but also smaller groups who can buy the systems and install them to store their own energy,” says MacDiarmid Institute Department of Chemical and Process Engineering Professor and Principal Investigator Aaron Marshall.

With $1 million in funding through a MBIE Smart Idea Grant and started through a MacDiarmid Institute Commercialisation Seed Grant, Sophie's research is identifying what factors in the battery’s electrode can be altered to improve battery performance.

“Developed before lithium-ion batteries, redox-flow battery reactions are slow, however the standard ways of measuring performance made it look like they were faster than they are.

“There hasn’t been much progression in making them a cost-effective alternative to Lithium-ion batteries because researchers have been trying to solve the wrong problem,” says Aaron.

“We didn’t know that the bottleneck was due to the misinterpretation of many redox-flow battery measurements.

“Reactions take place in the electrode which dictates the power output of the battery. I am looking at ways to speed up reactions to improve performance which translates into reducing the size of the electrode therefore reducing the battery size and cost.”

Initially not knowing if research “was her thing”, Sophie found trying to solve problems and make the research work was “really interesting”.

With a minor in Energy Processing Technologies, research in renewable energy technology was a natural progression; something made possible with a UC doctoral scholarship.

Recipient of the 2023 KiwiNet Emerging Innovator Programme Award, Sophie has been working with a commercial mentor and in workshops to build her knowledge on market validation, commercialisation, and pitching.

“Finding out whether your research is useful, and if people want it is important. I’ve been getting a commercial perspective on the research and where it could go,” says Sophie.

Recently back from Europe where she spoke to flow battery manufacturers about market validation for her research.

“Naturally most commercial flow battery manufacturers keep details of their battery performance and test procedures under wraps. We believe our research has some advantages, but we need to find out if that translates into their final product,” says Aaron.

“These discussions could help identify potential business models through licensing, sales or building our own batteries.”

Sophie has been exploring what industry is looking for in an electrode, what their current problems are and if there is feasible demand for putting money into creating electrode material as well as finding out how industry test new electrode materials which will help inform the final stages of her research.