Synthesis and electrochemical energy storage performance of biomass-based porous hierarchical activated carbon-polyaniline composites

To fabricate high performance energy storage devices with low cost, this work proposed a facile method to prepare biomass-based hierarchical activated carbon-polyaniline composites (HAC-PANI) via an in-situ chemi-cal polymerization method, and their applications in supercapacitors (SCs) and zinc-ion hybrid supercapacitors (ZHSCs) were investigated. The results show that hierarchical porous structure and high specific area of HAC provide growth sites for PANI and effectively reduce the agglomeration of PANI and meanwhile promote the transport of electrolyte ions, and degrease the charge transfer resistance. When the mass ratio of HAC to aniline monomer (An) is 1∶2, uniform PANI nanoparticles were observed growing on HAC, and the resulting composite (HAC-2PANI) electrode exhibits the optimum performance. Under the three-electrode system, the mass specific capacitance of HAC-2PANI reaches as high as 415.6 F·g−1(@1 A·g−1). The HAC-2PANI based all-solid supercapacitor (s-HAC-PANI-SC) displays a specific capacitance of 217.4 F·g−1(@1 A·g−1), an energy density of 26.5 W·h·kg−1 and a power density of 1875.0 W·kg−1. The zinc-ion hybrid supercapacitor (HAC-PANI-ZHSC) constructed with HAC-2PANI as the cathode and Zn foil as the anode exhibits a high specific capacity of 91.8 mA·h·g−1(@0.2 A·g−1), a remarkable energy density of 64.3 W·h·kg−1, and a power density of 140.0 W·kg−1, indicating promising potentials of biomass-based carbon composites for high performance and low cost electrochemical energy storage devices. © 2022 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.