Fabrication of a flexible and stretchable three-dimensional conductor based on Au-Ni@graphene coated polyurethane sponge by electroless plating

Flexible and stretchable electronics, which could function properly under different deformations, have attracted extensive attention recently, due to their widespread application potential. Among them, flexible and stretchable conductors have played a significant role in bridging stretchable electronics (e.g., flexible strain sensors and stretchable energy storage devices) and measured targets (e.g., human motion detection and multifunctional output devices). Although various types of fabrication method for flexible conductors have been reported, the fabrication of stretchable conductors exhibiting stretchability, conductive stability, and durability remains a challenge. Here, we developed a flexible and stretchable three-dimensional (3D) conductor by the electroless plating technique. The prepared flexible and stretchable conductor combines two strengths including the excellent conductivity of 3D gold- nickel@graphene coated polyurethane sponge (Au-Ni@GPUS) conductive networks and the flexibility of casting encapsulated PDMS. The resistance of the conductor ranges from original 2.5 Omega to 4.0 Omega when the applied strain increased from 0% to 30% for the first stretching-releasing cycle. And after 1000 stretching-releasing cycles, the original resistance exhibited a small increase to 3.1 Omega, while the resistance under 30% applied strain was 6.0 Omega which well illustrates the conductive stability and durability. Besides, the resistance of the conductor is retained even after 1000 cycles of bending (the bending angle ranges from 0 degrees to 180 degrees) and twisting (the twisting angle ranges from 0 degrees to 180 degrees), confirming the excellent conductivity of the conductor. Additionally, the fabricated flexible and stretchable conductor has been successfully applied as a flexible interconnect of light-emitting diodes and a stretchable mobile phone charging interconnect.