High Performance Inkjet -Printed and Flexible NiO Supercapacitors

Name of the conference: European Materials Research Society (E-MRS) Conference

Date of publication: 26 - 31 May 2019

Abstract: The miniaturisation of modern electronics along with the fast growth of autonomous wireless sensors, internet-of-things and wearable electronics, has stimulated the need for self-powered systems via energy harvesting from various ambient energy sources. Energy harvesting units usually require an energy-storage device to compensate for their power discontinuities and to ensure energy delivery over prolonged periods of time. In this work, we demonstrate the fabrication and integration of fully solution processed, co-planar NiO micro-supercapacitors through inkjet printing; thus, offering a path to readily scalable fabrication processes on large-area, flexible substrates at the fraction of the cost of traditional fabrication methods. Due to the high-capacity properties of NiO, the devices exhibit high areal capacitance of 75 mF·cm-2 per electrode and 13 mF·cm-2 as a whole device at 5 mV·s-1. The devices show ultra-high rate (up to 30 V·s-1) owing to the surfactant based saturated magnesium perchlorate gel electrolyte which is believed to form ion paths that facilitate in greater ion mobility. Importantly, we demonstrate that the inkjet-printed NiO thin film electrodes - consolidated from nanoparticles containing non-ionic surfactant - show over 10 orders of magnitude higher conductivity compared to single crystal NiO, which further enhances the charge transport pathways during charge-discharge cycles of the devices.