title: Surface Modified Nanocellulose Fibers Yield Conducting Polymer-Based Flexible Supercapacitors with Enhanced Capacitances.
abstract: 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 g(-1)) and volumetric (122 F cm(-3)) capacitances at high current densities (300 mA cm(-2) ≈ 33 A g(-1)) until date reported for conducting polymer-based electrodes with active mass loadings as high as 9 mg cm(-2). 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 cm(-3) and 3 W cm(-3) 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.
authors.affiliation: †Department of Chemistry-The Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala, Sweden.
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Wang
authors.affiliation: ‡Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Carlsson
authors.affiliation: ‡Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Petter
authors.initials: P
authors.lastname: Tammela
authors.affiliation: ‡Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Kai
authors.initials: K
authors.lastname: Hua
authors.affiliation: ‡Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: †Department of Chemistry-The Ångström Laboratory, Uppsala University, Box 538, SE-751 21 Uppsala, Sweden.
authors.forename: Leif
authors.initials: L
authors.lastname: Nyholm
authors.affiliation: ‡Nanotechnology and Functional Materials, Department of Engineering Sciences, The Ångström Laboratory, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Strømme
keywords: capacitance; conducting polymers; energy storage devices; modified nanocellulose; porosity optimization