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Paper-based transparent flexible thin film supercapacitors were fabricated using CNF-[RGO]n hybrid paper as an electrode material and charge collector. Owing to the self-anti-stacking of distorted RGO nanosheets and internal electrolyte nanoscale-reservoirs, the device exhibited good electrochemical performance (about 1.73 mF cm(-2)), and a transmittance of about 56% (at 550 nm).

Flexible supercapacitors with considerable energy storage performance from green/sustainable materials have attracted significant attention in many fields, such as portable and wearable electronics. In this work, flexible cellulose nanofibers/reduced graphene oxide/polypyrrole (CNFs/rGO/PPy) aerogel electrodes with well-defined three-dimensional porous structures are prepared using citric acid-Fe3+ (CA-Fe3+) complexes as oxidant precursors to command the deposition of PPy. The in situ gradual release of Fe3+ leads to the formation of thin and uniform polypyrrole in the composites. A flexible all-solid-state supercapacitor is then prepared by the CNFs/rGO/PPy aerogel film electrode and poly­(vinyl alcohol) (PVA)/H2SO4 gel electrolyte and separator. Due to the porous structure, high electrical conductivity, and remarkable wettability of the electrodes, the assembled supercapacitors show excellent electrochemical properties with maximum areal capacitance of 720 mF cm–2 (405 F g–1 for single electrode) at 0.25 mA cm–2 and good cycle stability (95% retention after 2000 cycles). The device with maximum energy density of 60.4 μW h cm–2 also exhibits nearly constant capacitance under different bending conditions, suggesting their great potential for applications in flexible electronics.

In recent years, much effort has been dedicated to achieve environmentally friendly, low cost, and excellent performance energy storage devices. In this work, cellulose nanofibers (CNFs)/multi-walled carbon nanotubes (MWCNTs) hybrid aerogels are prepared from CNFs/MWCNTs hydrogels by supercritical CO 2 drying using CNFs as an effective, environmentally friendly, and steady dispersant of MWCNTs. Allsolid-state flexible supercapacitors are fabricated using CNFs/MWCNTs hybrid aerogel film as the electrode material and charge collector. One-dimensional CNFs can effectively prevent the aggregation of MWCNTs, significantly enhance the re-wettability, and improve the utilization efficiency of the mesopores. Therefore, CNFs/MWCNTs hybrid aerogel film-based all-solid-state flexible supercapacitors exhibit excellent electrochemical properties: the specific capacitance is about 178 F g 21 . The flexible supercapacitors also exhibit excellent cyclic stability. Our work provides a novel method using low cost, and environmentally friendly CNFs to realize the full potential of the MWCNTs in an assembled bulk form. Taking its low cost and environmentally friendliness, CNFs/MWCNTs hybrid aerogel has great potential as the electrode material for all-solid-state flexible supercapacitors.

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