GoKawiilTL;DR: Scientists have built a quantum battery prototype that can produce an electrical current after charging in femtoseconds, marking a step forward for a technology that has largely remained theoretical and limited to small-scale lab experiments. The prototype is far from replacing conventional batteries, but it provides evidence that quantum effects could eventually enable faster energy transfer in quantum hardware and other specialized systems.
The device, developed by a team led by CSIRO quantum science researcher James Quach, is designed to take advantage of a quantum effect called superabsorption. In simple terms, the more molecules involved, the faster the system can absorb energy.
That is the opposite of what happens with conventional batteries, which generally take longer to charge as they get larger. The work does not mean quantum batteries are ready to replace those used in phones, laptops, or electric vehicles. The prototype stores only a small amount of energy and holds it for nanoseconds. Still, researchers say the experiment demonstrates that energy can be rapidly absorbed and extracted from a quantum battery.
The prototype uses an optical microcavity made of two mirrors separated by about 100 nanometers. The space between the mirrors is filled with organic dye molecules. A laser shines into the cavity, causing the light and molecules to interact strongly.
That interaction creates hybrid light-matter states. The molecules do not absorb energy independently, as they would in a classical system. Instead, they respond collectively.
The battery charges in femtoseconds, or quadrillionths of a second. It can retain energy for nanoseconds, about six orders of magnitude longer than the charging period.
Quach's team first demonstrated superabsorption in 2022. The newer experiment added the ability to extract an electrical current. The current remains small, but demonstrating it is an important step toward making a quantum battery useful beyond a physics experiment.
Quantum batteries are not expected to compete with conventional batteries simply by storing more energy. Their main attraction is the possibility of very fast charging and precise energy delivery.
Dario Ferraro, an associate professor of physics at the University of Genova, told the BBC that quantum batteries are intended to improve the speed and control of energy delivery rather than significantly increase the amount of energy a battery can store.
For now, the gap between the prototype and a useful power source remains wide. The device can hold only a few billion electron volts of energy and retains it for a very short time. A real-world system would need far greater capacity and much longer storage times.
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