New supercapacitor technology conducts power on copper wires

One of the fundamental challenges of battery technology is that lithium-ion batteries — by far the best general option for energy storage currently in wide commercial use — are intrinsically bulky and heavy.
A new research team at the University of Central Florida believes they can challenge that problem by turning copper wires into supercapacitors, then embedding those wires into the fabric of your clothing or the body of a device. In theory, they could also be embedded throughout the body of a car, significantly boosting total energy storage and freeing up space in the trunk, Extremetech reported.
According to nanotechnology researcher Jayan Thomas, his work on the concept involves first heating copper wire to create nano-whiskers — nanoscale-sized tendrils of metal that split off from the main wire. These are then protected by a sheath of naturally forming copper oxide (produced when the wire is heated in air). This turns the nanowhisker into an electrode. The entire structure is then wrapped in a plastic sheath, with a second set of nanowhiskers. The end result is a layered structure that looks like the feature image above — the copper wire in the center still conducts power, but the nanoscale structures store additional electricity as well.
Supercapacitor or battery?
Some write-ups are describing this as a type of battery, but the authors refer to it as a supercapacitor, and that designation appears to make more sense. The difference between supercapacitors and batteries, from a functional standpoint, is that batteries can store significantly more energy than a supercapacitor, but cannot release that energy nearly as quickly. Supercapacitors store less energy in total, but can discharge it nearly instantly. Supercapacitors tend to make poor batteries and vice versa, despite continuing research to find a way to blend the two.
The real question is how much energy can be feasibly stored in this type of copper wire and how effectively the nanostructures can be recharged without degrading. While the author talks of weight and bulk savings, copper is significantly heavier than metals like aluminum, and the extra shielding required will have its own weight. This ability to embed supercapacitor capability into virtually any surface could have a significant impact in some fields, but only if it winds up saving space or weight compared to existing methods. Efforts to incorporate traditional lithium-ion batteries into flexible cables have also been developed; LG demonstrated this type of structure two years ago.