Mass Transport Behaviors in Graphene and Polyaniline Heterostructure-Based Microsupercapacitors

The development of miniaturized energy storage components with high areal performance for emerging electronics depends on scalable fabrication techniques for thick electrodes and an in-depth understanding of the intrinsic properties of materials. Based on the coprecipitation behavior of electrically exfoliated graphene and reduced graphene oxide-templated polyaniline (PANi) nanoflake, this work develops a simple, green, low-cost, and scalable drop-casted technique to easily fabricate uniform thick electrodes (up to 80 mu m) on various substrates. Through using a direct laser writing process, planar microsupercapacitors can be readily attained. As-fabricated flexible all-solid-state microsupercapacitors exhibit an ultrahigh areal capacitance of 172mFcm(-2) at 0.1Acm(-2) and excellent cycling stability of 91% capacitance retention over 2000 cycles at a high current density of 1.0Acm(-2). Furthermore, based on the electrochemical quartz crystal microbalance research result, the pseudocapacitance contribution is mostly provided by the adsorption/desorption of SO42- anions during the protonation process of PANi. This work offers a simple strategy toward superior-performance micro-sized energy devices and a new perspective to understand the origin of the capacitance of composites and heterostructures.