文摘
We demonstrate that surface modified nanocellulose fibers (NCFs) can be used as substrates to synthesize supercapacitor electrodes with the highest full electrode-normalized gravimetric (127 F gp>鈥?p>) and volumetric (122 F cmp>鈥?p>) capacitances at high current densities (300 mA cmp>鈥?p> 鈮?33 A gp>鈥?p>) until date reported for conducting polymer-based electrodes with active mass loadings as high as 9 mg cmp>鈥?p>. By introducing quaternary amine groups on the surface of NCFs prior to polypyrrole (PPy) polymerization, the macropore volume of the formed PPy-NCF composites can be minimized while maintaining the volume of the micro- and mesopores at the same level as when unmodified or carboxylate groups functionalized NCFs are employed as polymerization substrates. Symmetric, aqueous electrolyte-based, devices comprising these porosity-optimized electrodes exhibit device-specific volumetric energy and power densities of 3.1 mWh cmp>鈥?p> and 3 W cmp>鈥?p> respectively; which are among the highest values reported for conducting polymer electrodes in aqueous electrolytes. The functionality of the devices is verified by powering a red light-emitting diode with the device in different mechanically challenging states.