Australian scientists build quantum battery with instantaneous charge, 1,000-fold gain in storage

Australia researchers have built and tested a quantum battery that can charge instantaneously and store 1000 times more energy than a previous version.

But this is still experimental quantum physics, meaning a 1000-times improvement is measured in going from storing nanoseconds of energy to microseconds. But RMIT PhD student and co-author Daniel Tibben is hopeful. 

“With the system that we have now we can theoretically get up to a second of storage,” he told Renew Economy.

The point of the research was to prove that adding a chemical layer to store the energy created by the quantum layer – without which it simply instantaneously charges and discharges – could work. 

And with version number four of a total of five different models, the researchers from RMIT University and CSIRO proved the theory worked. 

Unlike traditional batteries, which rely on chemical reactions, this quantum battery theory uses quantum superposition – the concept that an electron can exist in multiple states until it’s measured – and interactions between electrons and light to achieve faster charging times.

For this study published in PRX Energy, the team built and studied five optical cavities, a specially engineered structure, to trap and confine light between reflective surfaces. 

The fourth of these proved to be the winner, working best when two specific energy levels aligned perfectly, allowing energy to be stored.

Inside the cavity, molecules, from a fluorescent dye called rhodamine 6G, interact with photons and become energised into polaritons – particles that are part light, part matter. This is the charging layer.

A second layer using molecules from the light-sensitive chemical palladium tetraphenylporphyrin absorbs the energy. 

It’s in what’s called a low-energy triplet state, where two of three electrons spin in the same direction. That means it’s stable enough to provide long duration – in quantum terms at least – storage.

Tibben says the theoretical ability to get up to 1 second of storage is directly related to that triplet state.

“This work shows we can incorporate other chemical systems into these sorts of batteries and have them interact with polaritons, and that is a new order of understanding,” he says.

“What we’re comparing against is a previous demonstration by [co-author] James [Quach] at the CSIRO.

“Back in 2022 he was able to show that this class of quantum battery works, that we can store energy in these molecular states. But the fundamental issue with his battery was that… the battery discharges just as quickly. Charging the battery very quickly using these quantum effects also had the opposite effect.”

A longer-lasting battery using quantum physics is a while away yet.

While the study proves the concept and allows the team to design the next iteration of devices, a working quantum battery in devices such as sensors or watches is some time off, says co-author and RMIT chemical physicist Professor Daniel Gómez.

“It’s hoped one day quantum batteries could be used to improve the efficiency of solar cells and power small electronic devices,” he said in a statement.