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

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 H2 SO4 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.Partial funding from MINECO (grants no. MAT2015-68394-R, and MAT2017-87202-P MINECO/FEDER) and recognition from AGAUR (2017 SGR 870) are acknowledged. The ICN2 is supported by the Severo Ochoa program of the Spanish Ministry of Economy, Industry, and Competitiveness (MINECO, grant no. SEV-2013-0295) and funded by the CERCA program/ Generalitat de Catalunya.Peer reviewe