Polyaniline Based Ternary Hierarchical Microspheres for Supercapacitor Application

Abstract

With rapid advancements in renewable energy harvesters and flexible electronics, there is a dire need to develop energy storage devices (EEDs) that respond well to these applications. Supercapacitors are a type of EEDs with higher energy and power densities. This, combined with their ultra high cycle life makes them an attractive candidate to be used both as a standalone or coupled with other EEDs. The active material in supercapacitors can be broadly classified into three types: carbonaceous, conductive polymer, and metal oxides. Each category of materials has its own advantages and drawbacks. It is reasonable to formulate a ternary composite such that the advantage of one material effectively suppresses the drawback of the other. Herein, a ternary hierarchical microsphere (TMS) composed of polyaniline nanofibers, CeO2 nanorods, and reduced graphene is obtained through a simple and highly scalable spray-drying technique. The synthesized TMS was physiochemically characterized using XRD, FTIR, SEM, XPS, and gas adsorption surface analysis. Electrochemical analysis revealed that the optimized TMS possess high specific capacity (685 F g-1), good rate performance and excellent cycle life (~90% capacitance retention after 6000 cycles). An asymmetric device constructed using the TMS and rGO revealed a high specific energy density (46.3 W h kg-1) at a power density of 850 W kg-1 with a very stable cyclic performance. Thus, we demonstrate a simple yet effective strategy to produce high-performance supercapacitor material, which is highly scalable for industrial-scale production.