Carbon nanotube production is expanding and prices are falling.
To make the battery, a layer of nanotubes is first deposited in the form of "nanotube ink" onto a surface. This layer acts as the charge collector, which removes current from the battery.
Next, a layer of nanotube ink mixed with manganese oxide powder and electrolytes, which carries charge within the cell, is applied on top. This layer acts as the cathode. Finally, a piece of zinc foil – the anode – is applied.
"The batteries are similar to conventional batteries," says Gruner, "with the electrically conducting nanoscale networks replacing conventional metals and electrodes."
He adds that the designs should make it possible to get more power than a conventional design would from the same materials, , "an important factor for portable electronics applications."
The researchers also made supercapacitors using the inking technique and plan to combine these with batteries for applications requiring more power.
Furthermore, since both printed batteries and supercapacitors can be made entirely at room temperature, it should be possible to mass-produce them using established printing methods, Gruner says.
Gruner says his research team is working to increase power output and to demonstrate suitability of the designs for industrial production.