MrSeb writes: "Two European theoretical physicists have shown that it may be possible to build a near-perfect, entangled quantum battery. In the future, such quantum batteries might power the tiniest of devices — or provide power storage that is much more efficient than state-of-the-art lithium-ion battery packs. In a quantum system, some quantum states have energy that can be extracted, reducing the system to a passive, neutral energy state. Robert Alicki of the University of Gdansk in Poland, and Mark Fannes of the University of Leuven in Belgium, theorize that it should be possible to build a quantum battery that is full of energy-rich quantum states — and then, somehow, recharge it when you run out of juice. Better yet, the physicists also theorize that quantum entanglement could be used to create an even more efficient quantum battery. In essence, Alicki and Fannes say that you can link together any number of quantum batteries, allowing you to extract all of the stored energy in one big gulp. Their research paper goes on to say that with enough entanglement, these batteries would be perfect — with no energy lost/wasted during charge or discharge."