A micro-battery that can charge a thousand times faster than current batteries -- in the blink of an eye -- and a cellphone powered by that battery could jump start a car's dead battery. That vision of dramatically better energy-storage
technology is offered by new research by the University of Illinois at Champaign.
The researchers published their findings in the April 16 issue of Nature Communications. William P. King, the Bliss Professor of mechanical science and engineering and leader of the research team, said in a statement that "this is a whole new way of thinking about batteries."
He added that these kinds of batteries can "deliver far more power than anybody ever thought," and that this microtechnology could have a profound effect not only on electronic devices but in transportation.
Power Versus Energy
Currently, users choose between power and energy, so that, for instance, capacitors can release a lot of energy quickly but can only store a small amount, such as broadcasting a radio signal over a long distance for a very short time. For other applications, such as playing a radio over hours, battery sources can hold a fair amount of energy but release it slowly.
James Pikul, a graduate student and a first author of the research paper, told news media that "if you want high energy you can't get high power," and, conversely, it's "very difficult to get higher energy" if you want high power. But this new technology offers both, and can be tuned over a range of power-versus-energy tradeoffs.
With these kinds of battery sources, sensors or radio signals could broadcast an estimated 30 times farther or devices could be manufactured that were 30 times smaller. Imagine, the researchers said, charging a credit-card-thin smartphone is less than a second.
Batteries usually have an anode, which is the minus side, and a cathode, the plus side. The researchers employed a new kind of fast-charging cathode, developed a fast-charging anode, and integrated them at the microscale.
'Breaks Normal Paradigms'
King told the BBC that the electrodes in the team's battery "have small intertwined fingers that reach into each other," which allows the battery to have a very high surface area even though the overall volume is very small, and allows the two halves to get very close together so ions and electrons do not have far to travel.
The researchers also used a process developed by another team at the university, which creates a lattice out of very small polystyrene spheres and fills in the space with metal. The spheres are dissolved away, leaving a 3D metal scaffolding into which a nickel-tin alloy creates the anode and manganese oxyhydroxide is the cathode.
King said that, until now, the size of electronic devices have often been limited by the size of the battery, but now the battery can also be tiny. This is not, he said, "a progressive improvement over previous technologies," but instead it "breaks the normal paradigms of energy sources."
But this future may take awhile, as manufacturing processes for the new batteries still need to be developed, safety issues have to be addressed and electronic systems that use them need to be developed.