Meet the UL Scientist Building Ireland's Next-Generation Batteries

Part 6 of our Irish Renewable Energy Pioneers series

In early 2025, a research team at the University of Limerick announced something that had never been done before. They built a battery that runs on two different ions at the same time. Lithium and sodium, working together in the same cell, delivering double the energy capacity of a sodium-only battery.

The lead scientist? Dr. Hugh Geaney, an Associate Professor of Chemistry who is quietly rewriting the future of energy storage in a lab in Limerick.

While most of us think of batteries as the black box that powers our phones or stores solar energy at home, Geaney sees them as puzzles waiting to be solved. And he has just cracked one of the biggest.

The Battery Problem No One Talks About

Lithium-ion batteries are everywhere. They power your phone, your laptop, and increasingly, your car and your home. But lithium has two problems.

First, it is expensive. The price of lithium carbonate has swung wildly over the past five years, from under €10,000 per tonne in 2020 to over €70,000 in 2022, before crashing back down. That volatility makes planning difficult for battery manufacturers.

Second, lithium is geographically concentrated. Over 70% of global lithium production comes from Australia, Chile and China. Ireland has no domestic lithium supply.

Sodium, on the other hand, is abundant. You can extract it from seawater. It is cheap, stable and available everywhere. The problem is that sodium-ion batteries store less energy per kilogram than lithium-ion batteries. You need a bigger, heavier battery to store the same amount of power.

What if you could combine the two?

The World's First Dual-Cation Battery

That is exactly what Hugh Geaney and his team at UL did.

In a paper published in Nano Energy in 2025, they described the world's first full-cell battery that uses both lithium and sodium ions simultaneously. The lithium acts as a "capacity booster," while sodium remains the dominant ion.

The result? A battery with double the energy capacity of a sodium-only cell and up to 1,000 charge-discharge cycles. It also reduces reliance on cobalt, a metal linked to problematic mining practices.

The breakthrough was funded by Research Ireland and the Government of Ireland Postdoctoral Fellowship programme. It represents years of work on charge-storage mechanisms, materials science and nanowire engineering.

Geaney described it as "a significant step forward in the development of sustainable, high-performance energy storage systems."

Translation: better batteries for homes, cars and the grid, using materials that are cheaper and easier to source.

What This Means for Irish Homes and EVs

Dual-cation batteries are not in your garage yet. This is cutting-edge research, not a product you can buy from WattCharger tomorrow. But the implications are huge.

For home battery storage, higher energy density means you can store more solar energy in a smaller, lighter unit. That makes batteries easier to install, cheaper to transport and more practical for homes with limited space.

For electric vehicles, better batteries mean longer range, faster charging and lower costs. Ireland is aiming for nearly one million EVs on the road by 2030. We need better batteries to get there.

Geaney's work is part of a broader push at UL to develop next-generation energy storage. His research group is also working on magnesium-ion batteries, silicon nanowire anodes and nitrogen-doped graphene composites. In 2026 alone, his team published multiple peer-reviewed papers in ACS Applied Energy Materials and Journal of Power Sources.

From Lab to Living Room

Hugh Geaney is not a household name yet. He does not give TED talks or appear on morning television. He is a researcher who spends his days in a lab, synthesising materials, running charge-discharge tests and publishing papers with titles like "Hydrothermally Synthesized Calcium Tetragermanate Nanowires for Lithium-Ion Batteries."

But his work matters.

Every breakthrough in battery technology brings us closer to a grid powered entirely by renewables. Solar panels generate electricity when the sun shines. Wind turbines generate power when the wind blows. Batteries let us store that energy and use it when we need it, not just when nature provides it.

Ireland's renewable electricity capacity has grown from under 3 GW in 2010 to over 8 GW in 2026. Most of that growth has come from wind and solar. But to go further, we need better batteries. We need researchers like Hugh Geaney who are willing to spend years in the lab solving problems most people do not even know exist.

The Irish Battery Revolution

Geaney is not working alone. University of Limerick has become a hub for battery research, with expertise in materials science, electrochemistry and nanofabrication. UL's AMPeire project is developing advanced materials for next-generation batteries, and the university has partnerships with industry leaders across Europe.

This is part of a broader trend. Ireland is investing heavily in renewable energy research, from perovskite solar cells at Trinity College Dublin to grid-scale battery storage projects across the country.

The dual-cation battery is just the beginning.

Final Thoughts

Dr. Hugh Geaney and his team at the University of Limerick are building the batteries that will power Ireland's renewable future. Their work on dual-cation technology is a genuine world-first, and it shows that Ireland is not just adopting clean energy technology but inventing it.

From Nicholas Callan's giant battery in 1848 to Hugh Geaney's dual-cation breakthrough in 2025, Ireland has always been at the forefront of energy innovation. The tradition continues.

Ready to Future-Proof Your Home?

While dual-cation batteries are still in the lab, today's home battery systems are already helping Irish families store solar energy, cut electricity bills and become more energy independent.

Get in touch with WattCharger for a free consultation and find out how battery storage can work for your home.