Design and fabrication of printed paper-based hybrid micro-supercapacitor by using graphene and redox-active electrolyte

Abstract

Inspired by future needs of flexible, simple, and low-cost energy storage devices, smart graphene-based micro-supercapacitors on conventional Xerox paper substrates were developed. The use of redox-active species (iodine redox couple) was explored to further improve the paper device's performance. The device based on printed graphene paper itself already had a remarkable maximum volumetric capacitance of 29.6 mF cm⁻³ (volume of whole device) at 6.5 mA cm⁻³. The performance of the hybrid electrode with redox-active potassium iodide at the graphene surface was tested. Remarkably, the hybrid device showed improved volumetric capacitance of 130 mF cm⁻³. The maximum energy density for a graphene + KI device in H₂SO₄ electrolyte was estimated to be 0.026 mWh cm⁻³ . Thus, this work offers a new simple, and lightweight micro-supercapacitor based on low-cost printed graphene paper, which will have great applications in portable electronics.