Nanocellulose supported hierarchical structured polyaniline/nanocarbon nanocomposite electrode <i>via</i> layer-by-layer assembly for green flexible supercapacitors

Abstract

The development of a hierarchical structured multicomponent nanocomposite electrode is a promising strategy for utilizing the high efficiency of an electroactive material and improving the electrochemical performance. We propose cellulose nanofibril (CNF) aerogels with a nanoscale fiber-entangled network as the skeleton (<i>via</i> layer-by-layer (LbL) assembly) of electroactive materials polyaniline (PANi), carboxylic multiwalled carbon nanotubes (CMWCNTs), and graphene oxide (GO) to obtain structurally ordered polymer-inorganic hybrid nanocomposite electrodes for high-capacity flexible supercapacitors. The uniformly distributed multilayer nanoarchitecture, interconnected network, and hydrophilicity of the electrode provide a high specific surface area, excellent ion diffusion channels, and large effective contact area, thereby improving the electrochemical performance of the supercapacitor electrode. The specific capacitance of the CNF-[PANi/CMWCNT]₁₀ (CPC₁₀) and CNF-[PANi/RGO]₁₀ (CPR₁₀) electrodes reaches 965.80 and 780.64 F g^-1 in 1 M aqueous H₂SO₄ electrolyte, respectively; the corresponding values in PVA/H₃PO₄ electrolyte are 1.59 and 1.46 F cm^-2. In addition, the assembled symmetric supercapacitors show good energy densities of 147.23 and 112.32 mW h cm^-2, as well as excellent durability and flexibility. Our approach offers a simple and effective method for fabricating an ideal well-structured nanocomposite electrode for green and flexible energy storage devices <i>via</i> LbL assembly.