Melbourne, Australia – Researchers from RMIT University and Australia’s national science agency, CSIRO, have announced a significant breakthrough in quantum battery technology, extending the charge retention of a quantum battery by over 1,000 times compared to previous demonstrations. This development, published in PRX Energy, marks a crucial step toward the practical application of quantum batteries in areas like solar cells and microelectronics.
The Promise of Quantum Batteries
Quantum batteries are a revolutionary energy storage concept that leverages the principles of quantum mechanics, rather than traditional chemical reactions, to store and release energy. Unlike conventional batteries that store electrons and ions, quantum batteries store the energy from photons. These theoretical devices promise faster charging times, higher energy density, and longer lifespans. The concept, formally proposed just over a decade ago by Robert Alicki and Mark Fannes, harnesses quantum phenomena such as superposition and entanglement. In theory, quantum batteries charge faster as their size increases due to these quantum effects, a property known as superabsorption.
Overcoming Rapid Energy Loss: A Thousandfold Improvement
A major challenge for quantum batteries has been their tendency to rapidly lose stored energy through radiative emission, discharging almost as quickly as they charge. The recent study from RMIT University and CSIRO has addressed this limitation by extending the charge duration from nanoseconds to microseconds—a remarkable thousandfold improvement.
The research team focused on a Dicke-model-based quantum battery, which utilizes organic microcavities to facilitate superabsorption. Their work involved examining a multilayer microcavity where an active layer absorbs energy and transfers it to triplet states in a separate storage layer. They identified two pathways for this energy transfer, both relying on exciton-polariton resonances. The breakthrough in charge retention was achieved by precisely aligning two specific energy levels within the battery’s internal structure, which made the energy storage significantly more stable.
While microseconds may still seem like a short duration, this improvement is a critical proof-of-concept, establishing a strong foundation for future research and design of quantum batteries.
The Role of Nitrogen-Vacancy (NV) Centers in Diamonds
The concept of using diamond-based quantum systems, particularly nitrogen-vacancy (NV) centers, is highly relevant to quantum technologies, including quantum batteries and sensors. An NV center is a point defect in a diamond’s crystal lattice where a carbon atom is replaced by a nitrogen atom, and an adjacent carbon atom is missing. These imperfections give diamonds unique quantum properties, making them promising platforms for solid-state quantum technologies due to their long-lived spin coherence and efficient coupling to ambient fields.
Diamond quantum sensors, which utilize these NV centers, are already being explored for applications beyond energy storage, such as highly precise magnetic field sensing for biomedical imaging and even improving the accuracy of electric vehicle battery charge estimations. The sensitivity of these diamond-based sensors could potentially reduce the uncertainty in battery charge estimation in EVs, extending their driving range.
Challenges and Future Outlook
Despite the significant advancements, quantum batteries remain largely theoretical and in early laboratory experimental stages. Challenges persist, including the need to isolate quantum systems from their environment to prevent decoherence—the loss of quantum properties due to external interactions. However, some research suggests that a controlled amount of decoherence might even be beneficial for charge storage in certain contexts.
Researchers are continuously working to scale up these devices and integrate them into existing technologies. While quantum batteries are unlikely to power large objects like electric vehicles in the short to medium term, they hold immense potential for improving the efficiency of solar cells by enhancing low-light energy capture in photovoltaic materials, and for powering small electronic devices. The work on diamond-based systems contributes to this broader effort by providing platforms with robust quantum properties suitable for development in real-world conditions.
The recent breakthrough in charge retention is a testament to the ongoing progress in quantum battery research, bringing the world closer to a new era of energy storage.
