A team of international researchers managed to create graphene supercapacitors using a DVD burner with LightScribe. These capacitors are highly flexible, they have a max discharge rate 20 times higher than standard activated carbon capacitors, and three orders of magnitude higher than li-ion batteries, while offering energy densty comparable to a high-power li-ion battery!
The team, which was led by Richard Kaner of UCLA, started by smearing graphite oxide — a cheap and very easily produced material — films on blank DVDs. These discs are then placed in a LightScribe drive (a consumer-oriented piece of gear that costs less than $50), where a 780nm infrared laser reduces the graphite oxide to pure graphene. The laser-scribed graphene (LSG) is peeled off and placed on a flexible substrate, and then cut into slices to become the electrodes. Two electrodes are sandwiched together with a layer of electrolyte in the middle — and voila, a high-density electrochemical capacitor, or supercapacitor as they’re more popularly known.
Now, beyond the novel manufacturing process — the scientists are confident it can be scaled for commercial applications, incidentally — the main thing about LSG capacitors is that they have very desirable energy and power characteristics. Power-wise, LSG supercapacitors are capable of discharging at 20 watts per cm3, some 20 times higher than standard activated carbon capacitors, and three orders of magnitude higher than lithium-ion batteries. Energy-wise, we’re talking about 1.36 milliwatt-hours per cm3, about twice the density of activated carbon, and comparable to a high-power lithium-ion battery.