Biopolymer-chitosan based supramolecular hydrogels as solid state electrolytes for electrochemical energy storage

Flexible and wearable electronic systems based on 2D hydrogel composites

Flexible electronics is a rapidly developing field of study, which integrates many other fields, including materials science, biology, chemistry, physics, and electrical engineering. Despite their vast potential, the widespread utilization of flexible electronics is hindered by several constraints, including elevated Young's modulus, inadequate biocompatibility, and diminished responsiveness. Therefore, it is necessary to develop innovative materials aimed at overcoming these hurdles and catalysing their practical implementation. In these materials, hydrogels are particularly promising owing to their three-dimensional crosslinked hydrated polymer networks and exceptional properties, positioning them as leading candidates for the development of future flexible electronics.

Polysaccharide-based nanoassemblies: From synthesis methodologies and industrial applications to future prospects

Polysaccharides, due to their remarkable features, have gained significant prominence in the sustainable production of nanoparticles (NPs). High market demand and minimal production cost, compared to the chemically synthesised NPs, demonstrate a drive towards polysaccharide-based nanoparticles (PSNPs) benign to environment. Various approaches are used for the synthesis of PSNPs including cross-linking, polyelectrolyte complexation, and self-assembly. PSNPs have the potential to replace a wide diversity of chemical-based agents within the food, health, medical and pharmacy sectors. Nevertheless, the considerable challenges associated with optimising the characteristics of PSNPs to meet specific targeting applications are of utmost importance. This review provides a detailed compilation of recent accomplishments in the synthesis of PSNPs, the fundamental principles and critical factors that govern their rational fabrication, as well as various characterisation techniques. Noteworthy, the multiple use of PSNPs in different disciplines such as biomedical, cosmetics agrochemicals, energy storage, water detoxification, and food-related realms, is accounted in detail. Insights into the toxicological impacts of the PSNPs and their possible risks to human health are addressed, and efforts made in terms of PSNPs development and optimising strategies that allow for enhanced delivery are highlighted. Finally, limitations, potential drawbacks, market diffusion, economic viability and future possibilities for PSNPs to achieve widespread commercial use are also discussed.

State-of-the-art advances in nanocomposite and bio-nanocomposite polymeric materials: A comprehensive review

The modern eco-friendly materials used in research and innovation today consist of nanocomposites and bio-nanocomposite polymers. Their unique composite properties make them suitable for various industrial, medicinal, and energy applications. Bio-nanocomposite polymers are made of biopolymer matrices that have nanofillers dispersed throughout them. There are several types of fillers that can be added to polymers to enhance their quality, such as cellulose-based fillers, clay nanomaterials, carbon black, talc, carbon quantum dots, and many others. Biopolymer-based nanocomposites are considered a superior alternative to traditional materials as they reduce reliance on fossil fuels and promote the use of renewable resources. This review covers the current state-of-the-art in nanocomposite and bio-nanocomposite materials, focusing on ways to improve their features and the various applications they can be used for. The review article also investigates the utilization of diverse nanocomposites as a viable approach for developing bio-nanocomposites. It delves into the underlying principles that govern the synthesis of these materials and explores their prospective applications in the biomedical field, food packaging, sensing (Immunosensors), and energy storage devices. Lastly, the review discusses the future outlook and current challenges of these materials, with a focus on sustainability.

Living electronics: A catalogue of engineered living electronic components

Biology leverages a range of electrical phenomena to extract and store energy, control molecular reactions and enable multicellular communication. Microbes, in particular, have evolved genetically encoded machinery enabling them to utilize the abundant redox-active molecules and minerals available on Earth, which in turn drive global-scale biogeochemical cycles. Recently, the microbial machinery enabling these redox reactions have been leveraged for interfacing cells and biomolecules with electrical circuits for biotechnological applications. Synthetic biology is allowing for the use of these machinery as components of engineered living materials with tuneable electrical properties. Herein, we review the state of such living electronic components including wires, capacitors, transistors, diodes, optoelectronic components, spin filters, sensors, logic processors, bioactuators, information storage media and methods for assembling these components into living electronic circuits.

Porosity Tunable Poly(Lactic Acid)-Based Composite Gel Polymer Electrolyte with High Electrolyte Uptake for Quasi-Solid-State Supercapacitors

The growing popularity of quasi-solid-state supercapacitors inevitably leads to the unrestricted consumption of commonly used petroleum-derived polymer electrolytes, causing excessive carbon emissions and resulting in global warming. Also, the porosity and liquid electrolyte uptake of existing polymer membranes are insufficient for well-performed supercapacitors under high current and long cycles. To address these issues, poly(lactic acid) (PLA), a widely applied polymers in biodegradable plastics is employed to fabricate a renewable biocomposite membrane with tunable pores with the help of non-solvent phase inversion method, and a small amount of poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) is introduced as a modifier to interconnect with PLA skeleton for stabilizing the porous structure and optimizing the aperture of the membrane. Owing to easy film-forming and tunable non-solvent ratio, the porous membrane possesses high porosity (ca. 71%), liquid electrolyte uptake (366%), and preferable flexibility endowing the GPE with satisfactory electrochemical stability in coin and flexible supercapacitors after long cycles. This work effectively relieves the environmental stress resulted from undegradable polymers and reveals the promising potential and prospects of the environmentally friendly membrane in the application of wearable devices.

Sustainable Natural Bio-Origin Materials for Future Flexible Devices

Flexible devices serve as important intelligent interfaces in various applications involving health monitoring, biomedical therapies, and human-machine interfacing. To address the concern of electronic waste caused by the increasing usage of electronic devices based on synthetic polymers, bio-origin materials that possess environmental benignity as well as sustainability offer new opportunities for constructing flexible electronic devices with higher safety and environmental adaptivity. Herein, the bio-source and unique molecular structures of various types of natural bio-origin materials are briefly introduced. Their properties and processing technologies are systematically summarized. Then, the recent progress of these materials for constructing emerging intelligent flexible electronic devices including energy harvesters, energy storage devices, and sensors are introduced. Furthermore, the applications of these flexible electronic devices including biomedical implants, artificial e-skin, and environmental monitoring are summarized. Finally, future challenges and prospects for developing high-performance bio-origin material-based flexible devices are discussed. This review aims to provide a comprehensive and systematic summary of the latest advances in the natural bio-origin material-based flexible devices, which is expected to offer inspirations for exploitation of green flexible electronics, bridging the gap in future human-machine-environment interactions.

Food seasoning-derived gel polymer electrolyte and pulse-plasma exfoliated graphene nanosheet electrodes for symmetrical solid-state supercapacitors

Kitchen sea salt or table salt is used every day by cooks as a food seasoning. Here, it is introduced into a gel polymer (poly(vinyl) alcohol (PVA)-table salt) for use as an electrolyte, and an electrode was constructed from graphene nanosheets for use as symmetrical solid-state supercapacitors. The graphene sheets are prepared by a pulse control plasma method and used as an electrode material, and were studied by X-ray diffraction (XRD), Raman spectroscopy, as well as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). A specific capacitance of 117.6 F g-1 at 5 mV s-1 was obtained in a three electrode system with table sea salt as an aqueous electrolyte. For a symmetrical solid-state supercapacitor: graphene/PVA-table sea salt/graphene gave a good specific capacitance of 31.67 F g-1 at 0.25 A g-1 with an energy density of 6.33 W h kg-1 at a power density of 600 W kg-1, with good charge-discharge stability, which was 87% after 8000 cycles. Thus, the development of table sea salt as an environmentally friendly electrolyte has a good potential for use in energy storage applications.

A leather-based electrolyte for all-in-one configured flexible supercapacitors

Leather based gel electrolytes were prepared from the top down method, and integrated flexible supercapacitors were developed by this method.

Recent advances in conductive polymer hydrogel composites and nanocomposites for flexible electrochemical supercapacitors

Flexible electrochemical supercapacitors have shown great potential in the next-generation wearable and implantable energy-storage devices. Conductive polymer hydrogels usually possess unique porosity, high conductivity, and broadly tunable properties through molecular designs and structural regulations, thus holding tremendous promise as high-performance electrodes and electrolytes for flexible electrochemical supercapacitors. Numerous chemical and structural designs have provided unlimited opportunities to tune the properties of conductive polymer hydrogels to match the various practical demands. Various electrically and ionically conductive hydrogels have been developed to fabricate novel electrodes and electrolytes with satisfactory mechanical and electrochemical performance. This feature article focuses on the fabrication and applications of conductive polymer hydrogel composites and nanocomposites as respective electrodes and electrolytes for flexible electrochemical supercapacitors. First, we introduce the representative strategies to prepare electrically and ionically conductive polymer hydrogels. Second, conductive polymer hydrogel composites and nanocomposites as supercapacitor electrodes and electrolytes are presented and discussed. Finally, challenges and perspectives on conductive polymer hydrogel composites and nanocomposites for future flexible electrochemical supercapacitors are presented.

Nanotechnological approaches as a promising way for heavy metal mitigation in an aqueous system

The ever-rising environmental problems because of heavy metals emerging from anthropogenic activities pose an impending threat to all biota globally. Considering their persistence and possibility in biomagnification, they are prominent among pollutants. There has been an apparent shift of research interest in advancing cost-effective and competent technologies to mitigate environmental contaminants, specifically heavy metals. In the recent two decades, tailored nanomaterials (NMs), nanoparticles, and NM-based adsorbents have been emerging for removing heavy metal pollution on a sustainable scale, especially the green synthesis of these nanoproducts effective and nonhazardous means. Hence, this review explores the various avenues in nanotechnology, an attempt to gauge nanotechnological approaches to mitigate heavy metals in the aqueous system, especially emphasizing the recent trends and advancements. Inputs on remediating heavy metal in sustainable and environmentally benign aspects recommended future directions to compensate for the voids in this domain have been addressed.

Raw cellulose/polyvinyl alcohol blending separators prepared by phase inversion for high-performance supercapacitors

The development of a biodegradable cellulose-based separator with excellent performance has been of great research significance and application potential for the green development of supercapacitors. Herein, the regenerated porous cellulose/Polyvinyl alcohol films (CP-10, CP-15, CP-20, CP-25) with different mass ratio were successfully fabricated by a simple blending and phase inversion process. Their electrochemical properties as separators in assembled supercapacitor were evaluated. Fourier transform infrared spectroscopy and x-ray diffraction analysis indicate that intermolecular and intramolecular hydrogen bonding existed between cellulose and polyvinyl alcohol of the CP films. Compared with other CP films, the CP-20 film shows higher mechanical strength (28.02 MPa), better wettability (79.06°), higher porosity (59.69%) and electrolyte uptake (281.26 wt%). These properties of CP-20 are expected to show better electrochemical performance as separator. Indeed, the electrochemical tests, including electrochemical impedance spectroscopy, cyclic voltammetry, galvanostatic charge discharge, demonstrate that the SC-20 capacitor (with CP-20 as separator) shows the lowest equivalent series resistance of 0.57 Ω, the highest areal capacitance of 1.98 F cm^-2 at 10 mV s^-1, specific capacitance of 134.41 F g^-1 and charge-discharge efficiency of 98.62% at 1 A g^-1 among the four capacitors with CP films as separators. Comparing the assembled SC-40 and SC-30 with two commercial separators (TF4040 and MPF30AC) and SC-PVA with Polyvinyl alcohol (PVA) separator, the CV and GCD curves of SC-20 maintain the quasi rectangular and symmetrical triangular profiles respectively at different scan rates in potential window of 0-1 V. SC-20 exhibits the highest value of 28.24 Wh kg^-1 at 0.5 A g^-1 with a power density of 0.26 kW kg^-1, and 13.41 Wh kg^-1 at 10 A g^-1 with a power density of 6.04 kW kg^-1. SC-20 also shows the lowest voltage drop and the highest areal and specific capacitance. Moreover, SC-20 maintains the highest value of 86.81% after 4000 cycles compared to 21.18% of SC-40, 75.07% of SC-30, and 6.66% of SC-PVA, showing a superior rate capability of a supercapacitor. These results indicate that CP films can be served as promising separators for supercapacitors.

Ionotropic Gelation of Chitosan Flat Structures and Potential Applications

The capability of some polymers, such as chitosan, to form low cost gels under mild conditions is of great application interest. Ionotropic gelation of chitosan has been used predominantly for the preparation of gel beads for biomedical application. Only in the last few years has the use of this method been extended to the fabrication of chitosan-based flat structures. Herein, after an initial analysis of the major applications of chitosan flat membranes and films and their usual methods of synthesis, the process of ionotropic gelation of chitosan and some recently proposed novel procedures for the synthesis of flat structures are presented.

In Situ Formation of "Dimethyl Sulfoxide/Water-in-Salt"-Based Chitosan Hydrogel Electrolyte for Advanced All-Solid-State Supercapacitors

Biodegradable hydrogel electrolytes are particularly attractive in the fabrication of all-solid-state supercapacitors due to environmental benignity and avoiding of leakage. The introduction of "water-in-salt" (WIS) electrolytes into hydrogels will further broaden the electrochemical stability window of aqueous supercapacitors significantly. Meanwhile, the addition of an organic co-solvent can effectively overcome the inevitable salt precipitation and extend the temperature adaptability. Herein, an in situ cross-linking approach was demonstrated without any extra binder to obtain a "dimethyl sulfoxide/water-in-salt"-based (DWIS) chitosan hydrogel electrolyte. Interestingly, the addition of 4-7 mol L^-1 of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salts not only conforms to the criterion of WIS, but also promoted the successful gelation through the supramolecular complexation between Li⁺ -solvated complexes and chitosan chains. A hydrogel-based all-solid-state supercapacitor was fabricated using the DWIS chitosan hydrogel as the electrolyte and separator while nitrogen-doped graphene hydrogel (NG) was used as the electrode. The optimized supercapacitor with a wide operating voltage of 2.1 V showed a high specific capacitance of 107.6 F g^-1 at 1 A g^-1 , remarkable capacitance retention of 80.1 % after 5000 cycles, a superior energy density of 62.9 Wh kg^-1 at a power density of 1025.5 W kg^-1 , and excellent temperature stability in the range of -20 to 70 °C. These findings suggest that the as-prepared hydrogel electrolyte holds great potential in the practical application of high-performance solid-state energy storage devices.

An all-lignin-based flexible supercapacitor based on a nitrogen-doped carbon dot functionalized graphene hydrogel

In this manuscript, the synthesis of a nitrogen-doped carbon dot functionalized graphene hydrogel and its application as a supercapacitor electrode have been reported.

Doped photo-crosslinked polyesteramide hydrogels as solid electrolytes for supercapacitors

High-performance hydrogels play a crucial role as solid electrolytes for flexible electrochemical supercapacitors (ESCs). More specifically, all solid-state ESCs based on renewable, biodegradable and/or biocompatible hydrogels doped with inorganic salts as electrolytes are attractive not only because of their contribution to reducing resource consumption and/or the generation of electronic garbage, but also due to their potential applicability in the biomedical field. Here, computer simulations have been combined with experimental measurements to probe the outstanding capability as solid electrolytes of photo-crosslinked unsaturated polyesteramide hydrogels containing phenylalanine, butenediol and fumarate, and doped with NaCl (UPEA-Phe/NaCl). Atomistic molecular dynamics simulations have shown the influence of the hydrogel pore structure in the migration of Na⁺ and Cl^- ions, suggesting that UPEA-Phe/NaCl hydrogels prepared without completing the photo-crosslinking reaction will exhibit better behavior as solid electrolytes. Theoretical predictions have been confirmed by potentiodynamic and galvanostatic studies on ESCs fabricated using poly(3,4-ethylenedioxythiophene) electrodes and UPEA-Phe/NaCl hydrogels, which were obtained using different times of exposure to UV radiation (i.e. 4 and 8 h for incomplete and complete photo-crosslinking reaction). Moreover, the behavior as a solid electrolyte of the UPEA-Phe/NaCl hydrogel prepared using a photo-polymerization time of 4 h has been found to be significantly superior to those exhibited by different polypeptide and polysaccharide hydrogels, which were analyzed using ESCs with identical electrodes and experimental conditions.

Electrochemical double-layer supercapacitor using poly(methyl methacrylate) solid polymer electrolyte

The prime objective of the present article is to develop an efficient supercapacitor based on polymer electrolyte doped with salt. Solution cast technique was adopted to develop a solid polymer electrolyte of polymer poly(methyl methacrylate) (PMMA) as host polymer and salt potassium hydroxide (KOH) as a dopant. Incorporation of salt increases the amorphicity and assisted in conductivity enhancement. Moreover, doping of salt increases the overall conductivity of polymer electrolyte film. Electrochemical impedance spectroscopy reveals the enhancement in conductivity (four orders of magnitude) by salt doping. Fourier transform infrared shows the complexation and composite nature of films. Polarized optical microscopy shows the reduction in crystallinity, which is further confirmed by Differential scanning calorimetry. Fabricated electrochemical double-layer supercapacitor using maximum conducting polymer—salt electrolyte and symmetric carbon nanotubes electrodes shows specific capacitance of 21.86 F g−1.

Effect of Al2O3 on structural and dielectric properties of PVP-CH3COONa based solid polymer electrolyte films for energy storage devices

Nanocomposite polymer (NCP) films were prepared by doping sodium acetate (CH3COONa) in polymer of polyvinyl pyrrolidone (PVP) by complete dispersion of aluminum oxide (Al2O3) with different wt% proportions using solution cast method. The acquired NCP films were systematically characterized. The crystalline structure of the prepared NCP films was confirmed by XRD. The little agglomeration and grain sizes involved in the films were analyzed by SEM. The chemical bond formation and interchange reaction between the host, dopant salt and the nanofiller were confirmed by FTIR and Raman. The lowest energy bandgap values were observed to be 3.0 eV for the synthesized film with wt% ratio of PVP + CH3COONa:Al2O3 (80:20:1%). The highest ionic conductivity was found to be 1.05 × 10-3 S/cm for the prepared film with wt% ratio of PVP + CH3COONa:Al2O3 (80:20:1%). From the charge discharge characteristics it was concluded that the film with wt% ratio of PVP + CH3COONa:Al2O3 (80:20:1%) possesses long durability when compared to the other prepared films.

Dissolution-Crystallization Transition within a Polymer Hydrogel for a Processable Ultratough Electrolyte

Although nonliquid electrolytes have been developed rapidly under the condition of safe demand of energy storage devices, the inherent weaknesses in ionic conductivity, mechanical properties, or interfacial compatibility severely hinder their application under a harsh environment. Inspired by the hybridized characteristics of composite materials and the potential advantages of hydrated crystals, a processable crystal-type gel electrolyte with good comprehensive performance via the dissolution-crystallization transition of NaAc within hydrogel is creatively prepared. The use of NaAc crystal within a hydrogel leads to nearly 26 000 times greater modulus (474.24 MPa) and higher operating voltage (2.0 V) than the hydrogel without the crystal. The reliable supercapacitor using this electrolyte can work in extreme environment (-40 to 80 °C, even in the fire or in liquid nitrogen within a short time) benefiting from its phase-transition capacity. This investigation offers a facile and versatile way to construct an ideal gel electrolyte for next-generation energy storage devices.

Lamellarly Stacking Porous N, P Co-Doped Mo2 C/C Nanosheets as High Performance Anode for Lithium-Ion Batteries

Layered stacking and highly porous N, P co-doped Mo₂ C/C nanosheets are prepared from a stable Mo-enhanced hydrogel. The hydrogel is formed through the ultrafast cross-linking of phosphomolybdic acid and chitosan. During the reduction of the composite hydrogel framework under inert gas protection, highly porous N and P co-doped carbon nanosheets are produced with the in situ formation of ultrafine Mo₂ C nanoparticles highly distributed throughout the nanosheets which are entangled via a hierarchical lamellar infrastructure. This unique architecture of the N, P co-doped Mo₂ C/C nanosheets tremendously promote the electrochemical activity and operate stability with high specific capacity and extremely stable cycling. In particular, this versatile synthetic strategy can also be extended to other polyoxometalate (such as phosphotungstic acid) to provide greater opportunities for the controlled fabrication of novel hierarchical nanostructures for next-generation high performance energy storage applications.

Dielectric and transport properties of cationic polyelectrolyte membrane P(NVP-co-DMDAAC)/PVA for solid-state supercapacitors

A cationic polyelectrolyte with good ionic conductivity and dielectric properties was prepared; the membrane thickness is a key parameter.

A novel Mn/Co dual nanoparticle decorated hierarchical carbon structure derived from a biopolymer hydrogel as a highly efficient electro-catalyst for the oxygen reduction reaction

A Mn/Co dual nanoparticle-decorated hierarchical carbon structure was derived from a Zn/Mn/Co/chitosan composite hydrogel as a highly efficient electro-catalyst for the oxygen reduction reaction.

Impedance Spectroscopy as a Novel Approach to Probe the Phase Transition and Microstructures Existing in CS:PEO Based Blend Electrolytes

In this work the role of phase transition of PEO from crystalline to amorphous phases on DC conductivity enhancement in chitosan-based polymer electrolyte was discussed. Silver ion-conducting polymer electrolytes based on chitosan (CS) incorporated with silver nitrate (AgNt) is prepared via solution cast technique. Various amounts of polyethylene oxide (PEO) are added to the CS:AgNt system to prepare blend polymer electrolytes. Ultraviolet-visible (UV-vis) spectrophotometry is used to confirm that the blended samples containing AgNt salt exhibit a broad absorption peak. From optical micrograph images it is apparent that small white specs appear on the surface of the samples. The SEM results clearly show the aggregated silver nanoparticles. The enlargement of the crystalline area was observed from the morphological emergence and impedance plots. The phase separation in SEM images was observed at high PEO concentration. The XRD consequences support the morphological manifestation. In this study a new approach is offered to explore the microstructures existing in the blend electrolytes. The width of the semicircle linked to crystalline phase in impedance spectra was found to be increased with the increase of PEO concentration. A slow increase of DC conductivity was observed at low temperatures while above 333 K an immediate change in DC conductivity was obtained. The rapid rise of DC conductivity at high temperatures is correlated with the DSC results and impedance studies at high temperatures.

Nanocellulose-Mediated Electroconductive Self-Healing Hydrogels with High Strength, Plasticity, Viscoelasticity, Stretchability, and Biocompatibility toward Multifunctional Applications

Conducting polymer hydrogels (CPHs) have emerged as a fascinating class of smart soft matters important for various advanced applications. However, achieving the synergistic characteristics of conductivity, self-healing ability, biocompatibility, viscoelasticity, and high mechanical performance still remains a critical challenge. Here, we develop for the first time a type of multifunctional hybrid CPHs based on a viscoelastic polyvinyl alcohol (PVA)-borax (PB) gel matrix and nanostructured CNFs-PPy (cellulose nanofibers-polypyrrole) complexes that synergizes the biotemplate role of CNFs and the conductive nature of PPy. The CNF-PPy complexes are synthesized through in situ oxidative polymerization of pyrrole on the surface of CNF templates, which are further well-dispersed into the PB matrix to synthesize homogeneous CNF-PPy/PB hybrid hydrogels. The CNF-PPy complexes not only tangle with PVA chains though hydrogen bonds, but also form reversibly cross-linked complexes with borate ions. The multi-complexation between each component leads to the formation of a hierarchical three-dimensional network. The CNF-PPy/PB-3 hydrogel prepared by 2.0 wt % of PVA, 0.4 wt % of borax, and CNF-PPy complexes with a mass ratio of 3.75/1 exhibits the highest viscoelasticity and mechanical strength. Because of a combined reinforcing and conductive network inside the hydrogel, its maximum storage modulus (∼0.1 MPa) and nominal compression stress (∼22 MPa) are 60 and 2240 times higher than those of pure CNF/PB hydrogel, respectively. The CNF-PPy/PB-3 electrode with a conductivity of 3.65 ± 0.08 S m^-1 has a maximum specific capacitance of 236.9 F g^-1, and its specific capacitance degradation is less than 14% after 1500 cycles. The CNF-PPy/PB hybrid hydrogels also demonstrate attractive characteristics, including high water content (∼94%), low density (∼1.2 g cm^-3), excellent biocompatibility, plasticity, pH sensitivity, and rapid self-healing ability without additional external stimuli. Taken together, the combination of such unique properties endows the newly developed CPHs with potential applications in flexible bioelectronics and provides a practical platform to design multifunctional smart soft materials.

Pastes and hydrogels from carboxymethyl cellulose sodium salt as supporting electrolyte of solid electrochemical supercapacitors

Different carboxymethyl cellulose sodium salt (NaCMC)-based pastes and hydrogels, both containing a salt as supporting electrolyte, have been prepared and characterized as potential solid state electrolyte (SSE) for solid electrochemical supercapacitors (ESCs).The characteristics of the NaCMC-based SSEs have been optimized by examining the influence of five different factors in the capacitive response of poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes: i) the chemical nature of the salt used as supporting electrolyte; ii) the concentration of such salt; iii) the concentration of cellulose used to prepare the paste; iv) the concentration of citric acid employed during NaCMC cross-linking; and v) the treatment applied to recover the supporting electrolyte after washing the hydrogel. The specific capacitance of the device prepared using the optimized hydrogel as SSE is 81.5 and 76.8 F/g by means of cyclic voltammetry and galvanostatic charge/discharge, respectively, these values decreasing to 60.7 and 75.5 F/g when the SSE is the paste.

Fabrication of multi-stimuli responsive supramolecular hydrogels based on host–guest inclusion complexation of a tadpole-shaped cyclodextrin derivative with the azobenzene dimer

Multi-responsive supramolecular hydrogels, based on host–guest complexation of tadpole-shaped cyclodextrin with the azobenzene dimer, possess reversible sol–gel transition behaviors and better biocompatibility.