Cellulose-based functional gels and applications in flexible supercapacitors

In order to resolve the global crisis of fossil energy shortage and climate warming,the development of efficient energy storage devices is a significant topic at present.Supercapacitors as the novel type of energy storage devices have the unique advantages,including the fast charging/discharging behaviors,high-energy/power density,and stable cycling performance.Compared with traditional supercapacitors,flexible supercapacitors are environmen-tally friendly,light weight,small size and high safety.Therefore,flexible supercapacitors have a wide application prospect in emerging electronic devices.Due to its flexibility,biocompatibility,and structure designability,cellu-lose and its gel materials are gradually used as electrodes,separators and electrolytes in flexible supercapacitors.Several construction processes at molecular scale for high-performance cellulose gels are summarized.Meanwhile,this review covers the recent progress of developing the flexible supercapacitors and all-in-one supercapacitors based on cellulose functional gels.We finally discussed the potential challenges and opportunities for cellulose and its derived materials in new-style flexible supercapacitors and other electronic devices.

A Scalable Bacterial Cellulose Ionogel for Multisensory Electronic Skin

Electronic skin(e-skin),a new generation of flexible electronics,has drawn interest in soft robotics,artificial intelligence,and biomedical devices.However,most existing e-skins involve complex preparation procedures and are characterized by singlesensing capability and insufficient scalability.Here,we report on a one-step strategy in which a thermionic source is used for the in situ molecularization of bacterial cellulose polymeric fibers into molecular chains,controllably constructing an ionogel with a scalable mode for e-skin.The synergistic effect of a molecular-scale hydrogen bond interweaving network and a nanoscale fiber skeleton confers a robust tensile strength(up to 7.8 MPa)and high ionic conductivity(up to 62.58 mS/cm)on the as-developed ionogel.Inspired by the tongue to engineer the perceptual patterns in this ionogel,we present a smart e-skin with the perfect combination of excellent ion transport and discriminability,showing six stimulating responses to pressure,touch,temperature,humidity,magnetic force,and even astringency.This study proposes a simple,efficient,controllable,and sustainable approach toward a low-carbon,versatile,and scalable e-skin design and structure-performance development.