Xindi Yu, Professor Paul V. Braun and Huigang Zhang, University of Illinois at Urbana-Champaign
A step toward phones and laptops charging in seconds has been announced by the University of Illinois at Urbana-Champaign. Professor Paul Braun and his team at UIUC have created batteries that charge quick and retain a high energy density. Li-ion and NiMH, when rapidly charged, degrades the energy storage significantly over time. With Braun's battery, this is no longer an issue. The team have taken thin-film active material, like found in lithium-ion batteries, and wrap it into a three dimensional shape, which achieve high attractive volume and high current capabilities. Demonstrations in their lab have shown charge times in seconds. "10 to 100 times faster" than normal bulk electrodes, but perform exactly the same in existing devices.
The 3-D nano-structure of Braun's battery in self-assembling. Creating the material goes as such, a surface is coated with "tiny spheres" (Styrofoam) tightly packed to form a lattice. The space in between the spheres are filled with metal, then the spheres are melted (dissolved) to form a porous 3-D scaffold. Electropolishing uniformly etches the surface of the material, enlarging the pores, and making an open framework. Finally the frame is coated with a thin film active material. The result is a "bicontinuous electrode surface with small interconnects where lithium ions can move rapidly. The active material make the diffusion kinetics rapid. The metal framework makes for good conductivity.
Everyone would cheer if our gadgets charge in seconds using this battery form. But Braun has his eyes on automotive uses. Braun said, "If you had the ability to charge rapidly, instead of taking hours to charge the vehicle you could potentially have vehicles that would charge in similar times as needed to refuel a car with gasoline. If you had five-minute charge capability, you would think of this the same way you do an internal combustion engine. You would just pull up to a charging station and fill up." He is correct, the electric car would completely take over if the charge time was under 10 minutes.
Braun goes on, " We like that it's very universal, so if someone comes up with a better battery chemistry, this concept applies. This is not linked to one very specific kind of battery, but rather it's a new paradigm in thinking about a battery in three dimensions for enhancing properties."
Eavesdropper
pic L. Brian Stauffer, UIUC