The yarn - about the width of a human hair - is made of super-strong carbon nanotubes coated with small molecules of plastic, Stuff.co.nz reported.
Hundreds of layers of nanotubes are woven together with a thin metal wire.
One of the inventors, Gordon Wallace, an Australian Research Council laureate fellow at the University of Wollongong said that the spinning process takes collections of tubes and spins them into a fibre in a similar way you'd take wool and spin it into a fibre.
Carbon nanotubes are used in materials for their superior strength - they are stronger than steel - while plastic polymers are efficient electricity conductors.
"The advance we've made is to integrate the materials into structures and develop innovative ways of using them," Professor Wallace, a director of the Australian Research Council Centre of Excellence for Electromaterials Science, said.
Weaving the two nano materials together increased the amount of energy the thread could store, he said.
The fibre is also exceptionally flexible so it could be sewn or knitted into clothing to power wearable electronics.
Such devices could monitor people's movements during training or physiotherapy or power fashion accessories, he said.
The research is published in the journal Nature Communications.