Omnidirectional ly stretchable, high performance supercapacitors based on a graphene-carbon-nanotube layered structure

The development of stretchable energy storage systems for fully power-independent and stretchable devices for the next generation is increasing. Here, we report on a graphene-carbon-nanotube-layered structure for use as a stretchable electrode and its application in all-solid-state stretchable supercapacitors and various electronics. In this system, graphene serves as a floating track and carbon nanotubes convert external stress into the stretching motion of the electrode. The structure provides omnidirectional deformation without inhomogeneous interface stress and slip stress between active sites and the stretching passive components. The suggested system offers significant improvement over existing methodologies for fabricating stretchable energy storage systems and electronics in terms of density of capacitance, negligible passive volume, biaxial and twisted deformation, and durability. The integration of stretchable electrodes in various substrates and their application as all-solid-state, stretchable supercapacitors are demonstrated, and a high value of capacitance in the deformed state of 329 F g(-1) was achieved (based on mass of the graphene). The physical characteristics of the system are also revealed by first-principle calculations and three-dimensional finite-element methods. (C) 2015 Elsevier Ltd. All rights reserved.