In a new study, scientists have created a proof‑of‑concept quantum battery that can charge, store, and discharge energy – the closest step yet toward a working quantum battery.
Unlike traditional batteries, which rely on chemical reactions, quantum batteries use quantum superposition and interactions between electrons and light, offering the prospect of faster charging and enhanced storage capacity.
Fully functioning quantum batteries don’t yet exist, but advances like this could ultimately transform how we store and use energy.
The research, led by CSIRO – Australia's national science agency – with collaborators RMIT University and the University of Melbourne, was published today in Light: Science & Applications.
Co-Author and RMIT Ph.D. candidate Daniel Tibben said the results point to a surprising advantage for quantum batteries.
“Our study found quantum batteries charge faster as they get larger, which is not how today’s batteries work,” Tibben said. “It’s a sign that quantum batteries could one day outperform conventional energy-storage technologies.”
Co-Author and RMIT Professor of Chemical Physics Daniel Gómez said the proof-of-concept device is the closest we’ve ever come to producing a working quantum battery.
“We demonstrated a device that can be charged, store that energy, and then discharge it,” Gómez said. "This is an exciting development in a rapidly growing interdisciplinary field. Hopefully quantum batteries will soon no longer be a theoretical idea but something than can be built in the lab.”
Quantum batteries use key effects from quantum mechanics, like superposition and entanglement, rather than the chemical reactions that power today’s conventional batteries.
The prototype the researchers engineered is a tiny layered organic device that can be charged wirelessly using a laser.
Here is an exclusive Tech Briefs interview, edited for length and clarity, with Tibben.
Tech Briefs: What was the biggest technical challenge you faced while developing this quantum battery prototype?
Tibben: Our quantum battery prototype was fabricated by thin film deposition, creating an optical cavity to trap light and confine it to a very thin layer. At this confinement layer, we place our absorbing material, which undergoes a quantum process known as "superabsorption" to instantly capture the light energy. The internal thickness of the cavity is very, very important to the efficiency of this light collection, and so this required us to very deliberately model and refine the design of the multilayered cavity structure. Variations in thickness on the order of nanometres affect how this device behaves, so ensuring it is consistent is very important. Thankfully, these devices are fabricated using industry standard microelectronics techniques, so with the right equipment, these challenges can be managed. Additionally, because we used industry standard techniques, there is promise in scaling up these technologies in the future.
Tech Briefs: Can you explain in simple terms how it works please?
Tibben: You can think of molecules as little antennas that absorb light particles, known as photons. Molecules efficiently absorb photons that have the same energy (or "energy gap"). Instead, photons that are not the same energy (or not "in resonance") with the molecules are not absorbed well.
When molecules are placed in an optical cavity, we can strongly couple molecules and photons by matching the energy gap of the molecules with the energy of the photons.
The result are quantum states known as polaritons.
This is the benefit of this class of devices, because in these conditions, the molecules can absorb the light energy extremely quickly - much faster than if the molecules were not inside the optical cavity. This gives us our "quantum advantage" over traditional batteries - the fact that we can charge the quantum battery effectively instantly.
The issue we have is that energy also leaves the polaritons just as quickly as it is absorbed.
In a previous study, we showed that incorporating molecules with "triplet" states, we can extend the energy storage times by orders of magnitude than if the triplets weren't there. But, the question remained: how do we extract the energy in a usable state?
In this experiment, we show that when this quantum battery system with triplets is placed in a device based on a photodiode, to include electrodes and charge-carrying layers, we can effectively extract the absorbed energy as an electrical current. This is all while retaining the quantum advantage of instantaneous charging. This demonstrates, for the first time, the full cycle of a quantum battery, from instantly charging the device with light to energy extraction as electricity.
Tech Briefs: The article I read says, “The researchers are focusing on extending the energy storage time for quantum batteries, bringing them closer to being commercially viable.” My question is: Do you have any updates you can share?
Tibben: Storing the energy for extended times, once it is captured by the quantum battery, is still a major challenge. The team is working on this by incorporating other energy storage mechanisms with the device, such with capacitor structures or certain chemical reactions. While it is still early days, there are some really promising results coming out of this. There will be a lot to talk about once these are made public!
Tech Briefs: Do you have any other set plans for further research/work/etc.? If not, what are your next steps?
Tibben: As mentioned, the team is working on the incorporation of new energy storage mechanisms and systems to bring quantum batteries to a competitive level. We are always looking for interested parties to collaborate with to drive the research further.
We are also pursuing work into enhancing quantum sensing with similar device architectures. We recently published a study on incorporating quantum nanodiamond and hexagonal boron nitride particles (both of which are types of nano quantum sensors) in optical cavities to enhance their optical properties, which you can read about here: https://doi.org/10.1002/advs.202517593 .
In this study, we found that the cavity significantly modified the optical properties of the nano quantum sensors and enhanced their sensitivity to external stimuli. This shows great potential for optical cavities to not only enhance energy storage, but also to enhance other technologies which rely on the interactions of light and matter, such as sensing.
Tech Briefs: Is there anything else you’d like to add that I didn’t touch upon?
Tibben: I'd just like to emphasize the key finding from this study: We show that we can utilize the quantum advantage of quantum batteries, which is instantaneous charging, in a device which can be easily integrated into an electrical circuit. This is the first time this has been shown for a device of this class and is a critical step toward the development of a commercially competitive quantum battery.
Tech Briefs: Do you have any advice for researchers aiming to bring their ideas to fruition?
Tibben: Good mentorship is essential to developing good ideas. As an early career researcher or student, reaching out to experts in your field for advice or collaboration can really help you find opportunities to have your ideas funded and developed.
