Biotemplated hierarchical polyaniline composite electrodes with high performance for flexible supercapacitors

Abstract

Highly flexible and foldable supercapacitor devices assembled using biotemplated polyaniline composite electrodes are described for the first time in this paper. This electrode architecture provides a facile fabrication route for creating abundant multiscale structures by using a rose flower design based on natural resources and facilitates designing a hierarchical ordering morphology that improves the redox exchange and ionic diffusion resistance between the electrodes and electrolyte. The polyaniline composite was prepared using a replica technique and synthesized through in situ oxidative polymerization by using aniline with reduced graphene oxide. The biotemplated electrodes show a high electrochemical specific capacitance of 626 F g⁻¹ at a current density of 1 A g⁻¹ in a three-electrode system, an excellent mechanical strength for enduring Z-type folding, and high cycling stability with a capacity retention of 87% (545 F g⁻¹). Furthermore, in cyclic voltammetry analysis, the prototype devices exhibit extraordinary elasticity without side reactions in various bending angles. Regarding electrochemical performance, the device responds with a high energy density of 5.06 W h kg⁻¹ and a high power density of 1685 W kg⁻¹ when based on composite thin film electrodes and maintains 85% cycling retention as well as electrode performance after 1000 cycles. This study clearly reveals that fabricating hierarchical polyaniline composite electrodes through biotemplating yields high electrochemical performance and flexibility, making the electrodes useful in energy storage devices for portable electronic products.