Polyaniline and heteroatoms–enriched carbon derived from Pithophora polymorpha composite for high performance supercapacitor

Abstract

Due to their combined performance of faradic reaction and electrostatic charge accumulation mechanisms, composites of carbon and conductive polymers are prominent supercapacitor electrodes. However, low-cost efficient carbon materials to couple with conductive polymer remain a challenge for supercapacitor applications. Here, we report the fabrication of heteroatoms (Mg, Si, P, S, Cl, Ca, Fe, and N)-enriched hierarchical porous carbon by directly pyrolyzing the filaments of Pithophora polymorpha without chemical activation and successive electrodeposition of polyaniline on the prepared carbon. The resulting composite was used as a supercapacitor electrode that showed pseudocapacitor behavior (i.e., redox-based cyclic voltammograms), a high areal capacitance of 176 mF/cm2 at 1 mA/cm2, and maintained 95% of its initial capacitance after 1000 charge/discharge cycles. The composite electrode was capable to supply high energy density of 24.5 μWh/cm2 corresponding to a high-power density of 500 μW/cm2. The advanced capabilities of the composite electrode towards high-performance electrochemical energy storage may be attributed to the unique redox-active behavior of polyaniline, the active framework of porous heteroatoms-enriched hierarchical carbon, and improved electrical conductivity of the composite. This approach may provide a promising avenue to develop high-performance composite electrodes for supercapacitors from scalable, biological, and inexpensive biomass precursors, Pithophora polymorpha.