James Tour of Rice University discovered in 2014 that firing a laser at an inexpensive polymer burned off other elements and left a film of porous graphene. The researchers viewed the porous, conductive material as a perfect electrode for supercapacitors or electronic circuits.
The scientists have extended their work to make vertically aligned supercapacitors with laser-induced graphene on both sides of a polymer sheet. The sections are then stacked with solid electrolytes in between for a multilayer sandwich with multiple microsupercapacitors.
Tour claims the flexible stacks show excellent energy-storage capacity and power potential and can be scaled up for commercial applications. LIG can be made in air at ambient temperature, perhaps in industrial quantities through roll-to-roll processes.
The research has been reported in Applied Materials and Interfaces.
Capacitors use an electrostatic charge to store energy they can release quickly, to a camera’s flash, for example. Unlike chemical-based rechargeable batteries, capacitors charge fast and release all their energy at once when triggered. But chemical batteries hold far more energy. Supercapacitors combine useful qualities of both – the fast charge/discharge of capacitors and high-energy capacity of batteries – into one package.
LIG supercapacitors appear able to offer the fast charge/discharge of capacitors and high-energy capacity of batteries in a single package while having the added benefits of flexibility and scalability. The flexibility ensures they can easily conform to varied packages – they can be rolled within a cylinder, for instance – without giving up any of the device’s performance.
“What we’ve made are comparable to microsupercapacitors being commercialized now, but our ability to put devices into a 3-D configuration allows us to pack a lot of them into a very small area,” Tour said. “We simply stack them up.
“The other key is that we’re doing this very simply. Nothing about the process requires a clean room. It’s done on a commercial laser system, as found in routine machine shops, in the