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Bulk cellulose nanofibers (CNF)-based foam materials have attracted more and more attention in the field of energy storage and sensing because of their advantages of environmental protection, flexibility and cross-linked porous structure. However, the poor conductivity and low utilization efficiency of bulk CNF foam limit their wide application. Although some researchers have improved the conductivity of bulk CNF foam by carbonization, bulk CNF foam material will become fragile powders, not to mention flexibility, which seriously affects its application in energy and sensing fields. Herein, an attempt was made to fabricate a kind of non-carbonized bulk CNF@Ni foam hybrid by a combination of liquid reduction and freeze drying. During the process of the CNF@Ni foam preparation, the intermediate product CNF@NiCl2 shows good water storage and monitoring sensing characteristics, as well as it can be used as home decoration. What's more, the final CNF@Ni foam product can be directly assembled into a symmetrical supercapacitor that not only presents a good cycle stability, but also exhibits high gravimetric and volumetric energy densities of 38 Wh kg− 1 and 58 Wh L− 1, and simultaneously retains high power densities of 56 kW kg− 1 and 39 kW L− 1. Additionally, the hybrid also shows outstanding sensing properties. All in all, from the beginning to the end of the CNF@Ni foam preparation, various potential applications are explored in the whole process, which not only improves the utilization efficiency of CNF-based composites, but also explores more application scenarios of CNF-based composites. [ABSTRACT FROM AUTHOR]

Processing lignin into super-hydrophilic graphite by room-temperature chemical carbonization. [Display omitted] • Room-temperature carbonization has cost-effective and eco-friendly features. • Room-temperature carbonization afforded an 87% graphite yield. • Lignin-derived graphite has super-hydrophilicity. • Graphite-encapsulated liquid metal patterns have superb conductivity of 4.9 × 106 S/m. A cost-effective, and low-energy room-temperature cascade catalytic carbonization strategy is demonstrated for converting lignin into graphite with a high yield of 87 %, a high surface potential of −37 eV and super-hydrophilicity. This super-hydrophilic feature endows the lignin-derived graphite to be dispersed in a variety of polar solvents, which is important for its future applications. Encapsulating of liquid metals with the graphite for electrical circuit patterning on flexible substrates is also advocated. These written patterns show superb conductivity of 4.9 × 106 S/m, offering good performance stability and reliability while being repeatedly stretched, folded, twisted, and bent. This will offer new designs for flexible electronic devices, sensors, and biomedical devices. [ABSTRACT FROM AUTHOR]