Search

Cellulose composite nanopaper is extensively employed in flexible energy storage systems owing to their light weight, good flexibility and high specific surface area. Nevertheless, achieving flexible and ultrathin nanopaper supercapacitors with excellent electrochemical performance remains a challenge. Herein, surface cationization of bacterial cellulose (BC) nanofibers was conducted using 2,3-epoxypropyltrimethylammonium chloride (EPTMAC). Anion-doped polypyrrole (PPy) was incorporated onto the surface of the cationic bacterial cellulose (BCE) nanofibers by an interfacial electrostatic self-assembly process. The obtained PPy@BCE electrode exhibited excellent electrochemical performance, including an areal capacitance of 3988 mF cm -2 at 1.0 mA cm -2 and a capacitance retention of 97 % after 10,000 cycles. A laminated paper-forming strategy was adopted to design and fabricate all-in-one integrated flexible supercapacitors (IFSCs) using PPy@BCE nanopaper as electrodes and BC nanopaper as a separator. The IFSCs showed superior areal capacitance (3669 mF cm -2 at 1 mA cm -2 ), high energy density (193.7 μWh cm -2 at a power density of 827.3 μW cm -2 ), and outstanding mechanical flexibility (with no significant capacitance attenuation after repeatedly bending for 1000 times). The present strategy paves a way for the large-scale production of paper-based energy storage devices., Competing Interests: Declaration of competing interest There is no conflict of interest for this manuscript., (Copyright © 2023. Published by Elsevier B.V.)

Bacterial cellulose (BC)/polypyrrole (PPy) nanofibrous composites have been extensively studied in supercapacitors owing to their large specific surface area and excellent tensile strength. However, the inferior cycling stability due to structural pulverization of PPy impedes their potential applications. Herein, nanofibrous composite membranes of MXene, PPy and oxidized BC (TOBC) were prepared for flexible supercapacitor electrodes. The C6 primary hydroxyl groups of BC nanofibers were oxidized into aldehyde or carboxyl groups. Due to the enhanced interaction of TOBC with PPy and MXene, the TOBC nanofibers were horizontally wrapped on the MXene nanosheets and PPy was homogeneously deposited on the TOBC nanofibers. The flexible solid-state supercapacitors fabricated with the MXene@TOBC@PPy (TMP) electrodes achieved an areal specific capacitance of 928.9 mF cm−2 at 0.7 mA cm−2 and a capacitance retention of 85.5% after 5000 cycles. Therefore, the TMP electrodes could be a promising electrode material for flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy)/cellulose nanofiber (CNF) composites have been widely used in flexible energy storage devices because of their lightweight, inherent mechanical flexibility and large specific surface area. However, it is still a challenge to obtain PPy/CNF composite electrodes with high cycling stability. Herein, an electrostatic self-assembly strategy was adopted to deposit anion-doped PPy onto cationic poly(methacryloxyethyltrimethyl ammonium chloride)-grafted bacterial cellulose (BCD) nanofibers. The optimized PPy@BCD electrode demonstrated a high areal capacitance of 6208 mF cm−2 at a current density of 0.5 mA cm−2 and superior cycling stability (a capacitance retention of 100 % after 10,000 charge-discharge cycles at 10 mA cm−2). A quasi-solid-state anti-freezing flexible supercapacitor (AF-FSC) was designed by employing polyacrylamide organohydrogel electrolyte, yielding an areal capacitance of 2930.6 mF cm−2 at 1 mA cm−2 and a capacitance retention of 92.2 % after 1000 cycles at −20 °C. The present AF-FSC is expected to serve as a power source in real-life low-temperature applications. [ABSTRACT FROM AUTHOR]

Flexible strain sensors based on conductive organohydrogels have aroused wide range of interests owing to their potential utilization in human health and motion detecting. However, the mechanical performance and sensitivity of the organohydrogel sensors need to be further optimized. Herein, we have designed a dual-network organohydrogel utilizing poly(vinyl alcohol) (PVA) as raw materials, bacterial cellulose (BC) nanofibers as reinforcements, tannic acid (TA) as crosslinkers and multiwall carbon nanotubes (CNTs) as conducting fillers. The constructed C-PVA/BC/CNT organohydrogel shows good mechanical properties and high sensitivity. The resistance of the C-PVA/BC/CNT organohydrogel can be remarkably changed during deformation, demonstrating superior synchronicity between mechanical stimulus and electric signals, and thus can be used as piezoresistive strain sensors. In addition, the C-PVA/BC/CNT organohydrogel also exhibits favorable durability under different strains, and excellent cycling stability during loading/unloading processes. This C-PVA/BC/CNT organohydrogel can be used to monitor human motion and physiological activities, and has great potential applications in wearable electronic devices. [Display omitted] • A dual-network C-PVA/BC/CNT organohydrogel was designed. • The C-PVA/BC/CNT organohydrogel exhibited good mechanical properties and high conductivity. • The C-PVA/BC/CNT oganohydrogel demonstrated high sensitivity and desirable durability (up to 10,000 cycles) as flexible strain sensors. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy)/bacterial cellulose (BC) composite membranes are a promising kind of lightweight and flexible electrodes for supercapacitors. Herein, we explored a facile and efficient electrostatic self-assembly approach to uniformly depositing anion-doped PPy onto positively charged SnCl 2 -modifed BC (SBC). The obtained PPy@SBC electrode exhibited a high areal capacitance of 5718 mF cm−2 at a current density of 0.5 mA cm−2, a desirable capacitance retention of 83.1% at 5.0 mA cm−2 and excellent cycling stability (a capacitance retention of 86.8% after 10,000 cycles at 10 mA cm−2). A symmetric flexible supercapacitor was further assembled with the PPy@SBC electrodes, which delivered outstanding mechanical flexibility with negligible capacitance decay under different bent states. This study shows impressive potential in fabricating high-performance electrodes for flexible supercapacitors. [Display omitted] [ABSTRACT FROM AUTHOR]