Laser‐Scribed Graphene–Polyaniline Microsupercapacitor for Internet‐of‐Things Applications
Ali Khodabandehlo, Abolhassan Noori, Mohammad S. Rahmanifar, Maher F. El‐Kady, Richard B. Kaner, Mir F. Mousavi
Abstract
Abstract The push toward smart technologies and the Internet‐of‐Things (IoT) demands the development of miniaturized energy storage devices. Herein, a facile and scalable strategy is presented, based on laser reduction of graphene oxide into graphene followed by electrodeposition of polyaniline (PANi), to fabricate a substrate‐free supercapacitor. The fabricated supercapacitor is part of a flexible multifunctional integrated system comprising a thin‐film humidity sensor, a resistor, and a near field communication (NFC) antenna for IoT‐linked wireless communication with a smartphone. The integrated sensory system shares laser‐scribed graphene (LSG) as the same electrode material for all the components (supercapacitor, sensor, resistor, and NFC antenna). The symmetric LSG‐PANi||LSG‐PANi supercapacitor with wireless charging capability exhibits a near record‐high energy density of 0.407 mW h cm −3 , and excellent power density of 196 mW cm −3 , along with an outstanding rate capability (enduring high rates of over 1 V s −1 ). As a humidity sensor, the device demonstrates high resistance changes from 2000 kΩ at 0% relative humidity (RH) to 497 kΩ at 100% RH (15 kΩ per RH%) with a sub‐second scale (0.87 s) response time. This research paves the way for limitless applications of IoT across a wide spectrum of fields from healthcare to chip‐based electronics to environmental monitoring.