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Figure C1 KCNF-TENG builds multi-channel, fast-response self-powered wearable sensing systems for human–computer interaction and control hardware. [Display omitted] • kapok cellulose nanofiber film (KCNF) with superior optical, mechanical and biological properties was prepared. • The KCNF dielectric enhancement formed after mechanical treatment significantly improves the electrical output performance of TENG devices. • Self-powered human–computer interaction systems, e.g., five-finger input, smart medicine, and intelligent games, were established. As wearable devices in the fields of medical health, human–computer interaction, and motion detection continue to diversify in their materials and forms, they show vast application potential. Cellulose materials are emerging as prominent materials for fabricating flexible wearable electronic devices because of their favorable skin compatibility, cost-effectiveness, and abundance. However, there is little research on the use of kapok cellulose in wearable electronics. This study addresses this knowledge gap by exploring the high-yield production and waste recycling potential of kapok cellulose. To overcome the limitations of conventional cellulose films, such as poor flexibility, high haze, and limited light transmittance, a kapok cellulose nanofiber film (KCNF) with a transparency of > 90 % and a tensile strain of > 20 % is prepared. The use of the KCNF as a friction electric material in the triboelectric nanogenerator (TENG) improves its electrical output performance by 228 % and permits its comfortable long-term attachment to the skin for self-powered tactile sensing applications, including game control, text input, and smart medical devices. This study demonstrates that the exploration of KCNF materials expands the options available for developing wearable electronic devices with numerous potential applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multi-layer forming technology can integrate triboelectric material with electrode. • The all CPTENGs can exhibit excellent humidity, acid and alkali resistance. • The CPTENGs can yield a V OC , I SC and power density of 227.1 V, 6.9 μA and 520 mW/m2. • Matching CPTENGs with P-ZISC can obtain a self-charging power system (PSCPS). • The PSCPS can drive some miniaturized electronics for a long time. Triboelectric nanogenerators (TENGs) are regarded as a promising technology to drive the development of flexible/wearable electronics and self-powering sensor. Application of cellulose paper as the triboelectric positive materials makes TENGs more environmentally friendly. However, the limited output performance and stability in harsh environments and oxidation and corrosion of the metal electrodes have limited the practical application of cellulose paper based triboelectric nanogenerators (CPTENGs). Here, we have integrated cellulose paper-based triboelectric material and electrode in one sheet by using multi-layer forming technology in paper industry; the upper triboelectric layer shows excellent triboelectric positive performance, hydrophobicity and acid and alkali resistance, while the bottom electrode exhibits promise conductivity. The all CPTENGs can yield a maximum open-circuit voltage (V OC) of 227.1 V, a short-circuit current (I SC) of 6.9 μA. Furthermore, the V OC values of the all CPTENGs increase from 0.02 V to 225.1 V at the load resistance of 100 Ω∼10 GΩ; and a power density of 520 mW·m−2 is also obtained at a load resistance of 30 MΩ. Moreover, the V OC of CPTENGs not only retains up to 78 % of its initial value at a high relative humidity of 90 %, but also almost maintains unchanged in a wide range of the pH environment (pH = 1∼13). More importantly, the CPTENGs can be readily matched with paper-based zinc supercapacitor (P-ZISC) to act as an all paper based self-charging power system (PSCPS). The PSCPS is capable of driving various miniaturized electronics, such as electronic watch, temperature/humidity indicator, demonstrating its potential application in a sustainable power source for portable and green electronics. [ABSTRACT FROM AUTHOR]

[Display omitted] • GCOS with high DS was firstly synthesized in an acid-free aqueous medium. • The MIC of GCOS against S. aureus and E. coli is only 1/8 of COS. • GCOS-CFs show excellent antibacterial and antiviral activity. • Antibacterial and antiviral activities of GCOS-CFs are stable to water and heat. The worldwide spread of COVID-19 has put a higher requirement for personal medical protective clothing, developing protective clothing with sustained antibacterial and antiviral performance is the priority for safe and sustaining application. For this purpose, we develop a novel cellulose based material with sustained antibacterial and antiviral properties. In the proposed method, the chitosan oligosaccharide (COS) was subjected to a guanylation reaction with dicyandiamide in the presence of Scandium (III) triflate; because of the relatively lower molecular weight and water solubility of the COS, GCOS (guanylated chitosan oligosaccharide) with high substitution degree (DS) could be successfully synthetized without acid application. In this instance, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the GCOS were only 1/8 and 1/4 of that of COS. The introduction of GCOS onto the fiber endowed the fiber with extremely high antibacterial and antiviral performance, showing 100% bacteriostatic rate against Staphylococcus aureus and Escherichia coli and 99.48% virus load reduction of bacteriophage MS2. More importantly, the GCOS modified cellulosic fibers (GCOS-CFs) exhibit excellent sustained antibacterial and antiviral properties; namely, 30 washing cycles had negligible effect on the bacteriostatic rate (100%) and inhibition rate of bacteriophage MS2 (99.0%). Moreover, the paper prepared from the GCOS-CFs still exhibited prominent antibacterial and antiviral activity; inferring that the sheeting forming, press, and drying process have almost no effect on the antibacterial and antiviral performances. The insensitive of antibacterial and antiviral activity to water washing (spunlace) and heat (drying) make the GCOS-CFs a potential material applicable in the spunlaced non-woven fabric production. [ABSTRACT FROM AUTHOR]

[Display omitted] • A cocklebur structured fiber design was developed for polypyrrole modified fibers. • Formation of fibrous polypyrrole on the modified-fiber surface with high yield. • An all-in-one paper supercapacitor was produced with the papermaking technology. • Electrodes and separator were integrated by the inter-layer bonding of paper. In the era of miniaturization, low-cost, high mechanical stability and lightweight are the pre-requisites for the commercialization of smart-wearable supercapacitors (SCs). For this purpose, light-weight, binder-free, sustainable cellulose based thin-films with conductive polymers such as polypyrrole (PPy) have attained considerable attention. However, the delamination of the conductive materials in sandwich-type structures of SCs, particularly during the cyclic bending process at high current densities, is a great challenge for wearable SCs. To circumvent the problem of delamination of conductive materials, multi-layer forming concept that consists of three sequential steps (forming, pressing and drying) in papermaking technology has inspired us to prepare mechanically ultra-stable paper electrodes towards for wearable SCs. For this reason, we firstly adopted the multi-layer concept to design all-in-one paper flexible SCs by integrating PPy-modified cellulose fibers as electrodes, and un-modified cellulose paper as a separator. More importantly, a cocklebur like structure of PPy-modified cellulose fiber has been attained by the virtue of the strong inter-molecular hydrogen bonding between free hydroxyl groups on the surface cellulose fibers and PPy, resulting in increased PPy loading, and thus enhancing the electrochemical properties of the all-in-one paper supercapacitor. Furthermore, these hydroxyl groups facilitate the inter-layer bonding of the paper structure in the subsequent pressing and drying processes, favoring the integration of the electrodes and separator. Benefiting from the multi-layer forming concept and suitable morphology of PPy- modified cellulose, we have prepared an ultra-thin (150 μm) all-in-one paper SC with high areal specific capacitance (up to 562 mF cm−2), high energy density (up to 3.1 mWh cm−3) and high-power density (up to 414.9 mW cm−3). Moreover, the all-in-one paper SC shows excellent flexibility, with negligible specific capacitance loss by bending at 0° to 180° angles after repeating 1000 times. The proposed concept and supercapacitor fabrication process is scalable and can be readily implemented in a modern paper industry. [ABSTRACT FROM AUTHOR]

• Novel SiC/Pyrrolic-N doped carbon material have been synthesized from bamboo. • Inherent SiO 2 moieties in natural bamboo has been used as a sacrificial template. • The synergy of SiC and Pyrrolic-N has been demonstrated for Faradaic redox reactions. • Natural bamboo-based carbon materials deliver capacitance of 369 F g−1 at 0.5 A g−1. • Bamboo-based carbon materials deliver 100% capacitance retention after 5000 cycles. It is still challenging to prepare porous carbon materials following a facile, green and universal sacrificial template method from renewable biomass. For this purpose, bio-renewable bamboo is a natural silicon reservoir containing a significant amount of inherent silica that can act as a natural sacrificial template for the formation of porous carbon materials as well as a dopant. Herein, we firstly report the SiC/N dual doped bio-renewable carbon material via a facile, natural sacrificial template method. In this newly developed method, the inherently available SiO 2 nanoparticles have been utilized as the natural sacrificial template for creating the multi-porous architecture as well as for the generation of structural defects in the form of SiC nano-species. Additionally, the inherent nitrogen functional groups give rise to the formation of only pyrrolic-N species after pyrolysis. Furthermore, dual doping of SiC and pyrrolic-N species stimulate the faradaic redox reaction during the charge/discharge process and further increase the rate capability at higher current density with excellent electrochemical stability. Hence, the synergistic effect of SiC and N-pyrrolic dually doped carbon network gives rise to the formation of promising electrode material towards supercapacitors. Benefiting from the above unique features, the supercapacitor with the SNAC-1 electrode material delivers excellent capacitive behavior (369 F g−1 at 0.5 A g−1) in 1 M H 2 SO 4 electrolyte with 100% capacitance retention after 5000 charge–discharge cycles. More prominently, the all-solid state, symmetric supercapacitors assembled by SNAC-1 show outstanding capacitance of 162 F g−1 at 0.5 A g−1 and reveal high energy density (∼5.41 W h kg−1 at 0.5 kW kg−1 power density) and excellent cyclic stability. This work provides an ideal sustainable solution from bamboo source to prepare porous SiC/N composites for cost-effective supercapacitor's electrode materials. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have been investigated as a promising device to harvest mechanical energy into electricity. At present, paper-based triboelectric nanogenerators (P-TENGs) have been widely researched because paper features with lightweight, low cost, abundance, renewability and biodegradability. In this paper, the operating principles and operation modes of TENGs, the development progress and performance enhancement routes of P-TENGs are comprehensively reviewed. Additionally, the overview, challenges and opportunities of P-TENGs applications are also presented. [ABSTRACT FROM AUTHOR]

• The asymmetric hydrogel is adjusted and assembled by lignin and cellulose derivatives. • The hydrogel exhibits completely asymmetric adhesion, strength, and electriferous. • The hydrogel-based sensor has excellent skin adaptability and application stability. • The hydrogel can be applied to self-adhesive bioelectrodes and self-powered sensors. Mechanical adaptability, great wearability, application stability, and self-powered sensing characteristics are important requirements for hydrogel-based strain sensors. In this study, a novel double-layer hydrogel was fabricated with asymmetrical adhesion, strength, and electriferous properties. Wherein, the lignosulfonate sodium (LS)-borax mediated bottom hydrogel layer exhibits excellent softness (Young's modulus: ~14.2 kPa) and skin-adhesion (Adhesive strength: ~18.7 kPa) while the quaternary hydroxyethyl cellulose (QHEC) mediated top hydrogel layer demonstrates great mechanical strength (Young's modulus: ~101.3 kPa) and non-adhesive (Adhesive strength: ~2.2 kPa) properties. These complementary asymmetrical adhesion and strength properties endow the hydrogel-based sensor with exceptionally stable sensing performance and adaptive wearability; moreover, the lignocellulosic materials utilization plays a significant role in the designability, antibacterial and biodegradable properties. In addition, the synergy of negative LS (-) and positive QHEC (+) particles enables the double-layer hydrogel great self-powered sensing because of the directional movement of free ions initiated by the external mechanical stimulus. This study presents a hierarchical design idea of wearable electronics, which will have potential applications in many fields from wearable bioelectrodes to self-powered sensors. [ABSTRACT FROM AUTHOR]

• MXene can catalyze the ultrafast preparation of hydrogels by redox reaction. • MXene can regulate the internal structure and properties of the hydrogel. • Composite hydrogel has great stretchability (1400%) and recoverability. • Composite hydrogel can be used as a bioelectronic with adjustable adhesion. Re-stacking of 2D Ti 3 C 2 T X (MXene) nanosheets seriously limits their applications and development of effective strategies to overcome this issue remains challenging. Thus, an efficient method was proposed to rapidly fabricate (<20 min) a MXene nanosheets-catalyzed self-assembled, poly-acrylic acid (PAA) hydrogel with excellent conductivity, stretchability (~1400%), and anti-aggregation (>60 d) properties. In the proposed strategy, in-situ growth of TiO 2 nanoparticles (NPs) on MXene surfaces could effectively overcome the nanosheets restacking in solvents. Moreover, the reductive TiO 2 @MXene nanosheets not only catalyze the dissociation of the initiator generating sufficient radicals by redox reaction to initiate the ultrafast polymerization of AA monomers without heating, but also cross-link polymer chains (via chemical bonding) to produce hydrogel in a time scale of minutes instead of hours. Therefore, the MXene-catalyzed ultrafast self-assembly design effectively overcame the problem associated with the re-aggregation of nanosheets in hydrogels. More importantly, the structural, mechanical, swelling, adhesive, and conductive performances of the hydrogel could be adjusted by altering the TiO 2 @MXene contents. This strategy should be extended to almost all types of MXene-radical polymerized hydrogels with tunable structures and performances that have potential applications in the field of wearable bioelectronics. [ABSTRACT FROM AUTHOR]

• The redox SL-Fe3+ chelates can shorten the hydrogel gelation time by 99.67%. • The hydrogel obtained stretchable, conductive, adhesive, and UV-blocking properties. • The green SL-Fe3+ chelates imparts excellent self-healing properties of the hydrogel. • The rapid preparation of soft multifunctional coatings electronics was proposed. Developing an ecological and economical method for fabrication and application of polymer hydrogels is important for the hydrogel/coating electronics. Here, a dynamic oxidation and coordination system composed of sulfonated lignin (SL) and Fe3+ was introduced to assemble multifunctional Fe-SL-g-polyacrylic acid (PAA) hydrogel at 20 ℃ in a time scale of minutes instead of hours. The SL-Fe3+ system can rapidly activate the ammonium persulfate (APS, initiator), and then it instantaneously provides abundant semiquinone and hydroxyl radicals to accelerate the formation of polymer chains. Moreover, the functional SL-Fe3+ chelates can also reversibly crosslink the polymer chains to form multifunctional hydrogels. Surprisingly, the resultant hydrogel obtained charming extension ratio (up to 1680%), conductivity (up to 7.0 × 10-2 S·m−1), and adhesive strength (up to 36.4 kPa). This technology was also applied to rapidly fabricate a transparent (up to 81%, thickness: 2 mm), UV-blocking (up to 99.7%, thickness: 2 mm), adhesive, and conductive hydrogel coating on substrates. Besides, the dynamic coordination inside the hydrogel imparts desirable self-healing capabilities to damaged network, with up to 98.5% recovery in conductivity and 85.7% in extension ratio. In short, this technology based on the sustainable SL-Fe3+ system greatly facilitates the rapid and low-cost preparation of multifunctional hydrogel/coatings, which have promising industrial applications in human–machine electronics. [ABSTRACT FROM AUTHOR]