Researchers at the University of Illinois, Urbana-Champaign have developed a 3d nanostructure for battery cathodes that permits far faster charging and discharging without sacrificing energy storage capacity.
While supercapacitor batteries already have fast charging attributes, it’s at the expense of storage. According to Paul Braun, a professor of materials science and engineering, the system his team has developed provides capacitor-type power with the energy attributes of deep cycle batteries.
Braun’s group have demonstrated battery electrodes that can charge or discharge in a few seconds, up to 100 times faster than equivalent bulk electrodes, yet can perform normally in existing devices.
This technology may have major benefits for solar energy applications, both off-grid solar and grid connect. It could also been a boon for electric car batteries, which currently often need hours to recharge. “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,” says Professor Braun
The processes used to construct the battery are also currently utilised in the battery industry, so the technique could be scaled up for manufacturing.
The cathodes are constructed by coating a surface with tiny spheres that form a lattice. The space between and around the spheres is then filled with metal. The spheres are then dissolved, leaving behind a porous metal framework. Electropolishing then uniformly etches away the surface to enlarge the pores and make an open framework. The frame is then coated with a thin film of the active material.
The resulting structure features small interconnects that allow ions to rapidly move rapidly, offers rapid diffusion kinetics properties and a metal framework with good electrical conductivity.
The structure is general and Professor Braun says any battery material that can be deposited on the metal frame could be utilised. “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.”
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