LiCl Concentration Research Articles

Development of Gelatin Methacryloyl/Sodium Alginate Interpenetrating Polymer Network Hydrogels for Bone Regeneration by Activating the Wnt/β-Catenin Signaling Pathway via Lithium Release.

Hydrogels have gained significant attention as biomaterials due to their remarkable properties resembling those of the extracellular matrix (ECM). In the present investigation, we successfully synthesized interpenetrating polymer network (IPN) hydrogels using gelatin methacryloyl (GelMA) and sodium alginate (SA), incorporating various concentrations of lithium chloride (LiCl; 0, 5, and 10 mM), aiming to develop a hydrogel scaffold for bone regeneration. Notably, the compressive modulus of the IPN hydrogels remained largely unaffected upon the inclusion of LiCl. However, the hydrogel with the high concentration of LiCl exhibited reduced fragmentation after compression testing. Intriguingly, we observed a significant improvement in cellular biocompatibility, primarily attributed to activation of the Wnt/β-catenin signaling pathway induced by LiCl. Subsequently, we evaluated the efficacy of the newly developed IPN-Li hydrogels in a rat cranial defect model and found that they substantially enhanced bone regeneration. Nevertheless, it is important to note that the introduction of high concentrations of LiCl did not significantly promote osteogenesis. This outcome can be attributed to the excessive release of Li+ ions into the extracellular matrix, hindering the desired effect. Overall, the IPN-Li hydrogel developed in this study holds great promise as a biodegradable material for bone regeneration applications.

Effect of LiCl Electrolyte Concentration on Energy Storage of Supercapacitor with Multilayered Ti3C2Tx MXene Electrodes Synthesized by Hydrothermal Etching

The development of new electrode materials for electrochemical systems for various purposes is a significant and in-demand task of scientific research. Layered transition metal carbides and nitrides, known as MXenes, show great potential for use as electrodes in electrochemical energy storage devices operating in aqueous electrolytes. In this work, a multilayer Ti3C2Tx MXene was obtained from a Ti3AlC2 precursor and studied as the electrode material of a symmetrical supercapacitor with an aqueous LiCl electrolyte. The formation of the MXene structure was confirmed by the data from X-ray phase analysis and scanning electron microscopy. The X-ray diffraction pattern showed the disappearance of the main reflections related to the Ti3AlC2 phase and the shift of the reflection peak (002) from 9.4° to 6.7°, which indicated successful etching of the Al layers from the Ti3AlC2 precursor. At electrolyte concentrations of 1, 5, 10, and 20 M, the supercapacitors demonstrated high specific capacitances of 105, 120, 126, and 151 F·g−1 at a scan rate of 5 mV·s−1. In addition, an increase in the LiCl concentration contributed to the expansion of the potential window from 0.7 to 1 V. It was shown that the contribution of the surface capacitance to the total capacitance of the electrode is about 40% and depends little on the scan rate. In addition, the symmetrical supercapacitor with 5 M electrolyte showed good cyclic stability with capacitance retention of 88% over 10,000 cycles. The parameters of the main components of the physical processes of supercapacitors based on Ti3C2Tx were determined by the method of impedance spectroscopy.

Performance evaluation of PVA/PEO/LiCl composite as coated heat exchangers desiccants

Composite desiccants have led to a growing interest because of their eco-friendliness, sustainability, and excellent dehumidification properties. In this paper, we present a method for constructing a dehumidification composite of PVA/PEO/LiCl that is eco-friendly and recyclable. The results show that PVA/PEO/LiCl has better dehumidification performance than SG, SG/LiCl, PVA/PEO, and PVA/PEO/CaCl2 as coated heat exchangers desiccants. The addition of LiCl caused the internal hydrophilic polymeric hygroscopic carriers to work in concert with the membrane porosity. This resulted in a considerable increase in the membrane's hygroscopic rate and capacity, as well as improved mechanical qualities. As the concentration of LiCl was increased, the surface sealing of the PVA/PEO polymer improved dramatically, and the shape of the polymer-formed film changed from loose to firmly packed. The structural shift toward densification boosted the strength of the co-blended dehumidified films. With a PVA/PEO/LiCl ratio of 1:1:2.5 and the coating thickness of 10–15 µm, the greatest dehumidification effectiveness is achieved. During five subsequent sorption and desorption procedures, the sorption of PVA/PEO/LiCl remained between 70 and 75%, demonstrating its outstanding reusability and cycling stability.

Enroute to sub-300 °C operating Sn–Zn||Pb–Bi liquid metal battery by compositional engineering

Liquid metal battery (LMB) is considered a potential contender for grid-scale energy storage systems. However, high operating temperatures (>400 °C) leading to higher operational costs limit its commercial application. Therefore, the current work focuses on reducing the melting temperature of electrodes and electrolytes below 300 °C by compositional engineering. Moreover, this study utilizes earth-abundant elements like Zn (with less reliance on Li), in Zn–Sn||Bi–Pb LMB system. The composition of LiCl in the electrolyte is varied to optimize the battery performance, especially the energy efficiency and overpotential while maintaining an operating temperature of <275 °C. It is found that as the LiCl content in the electrolyte salt increases (5–30 Mol%), the overpotential of the battery decreases (0.9–0.3 V), and the energy efficiency of the charge-discharge process improves (14.5%–80.9%) owing to the better ionic conductivity of LiCl. For the optimized LiCl concentration of 30 Mol% LiCl in the electrolyte, the fabricated LMB exhibit good cyclability (no degradation till 100 cycles), a high discharging voltage plateau of 0.92 V, 24.6 mAh charge storage capacity, and a low operating temperature of 275 °C, which is the lowest operating temperature reported so far in a Zn-based LMB system.

Experimental study on the open adsorption performance of CAU-10-H and its composite adsorbent

On the basis of the method used by Reinsch and Solovyeva, the aluminum based MOF material CAU-10-H (CAU stand for Christian-Albrechts-University) was synthesized by multiplying the amount of aluminum sulfate octahydrate and isophthalic acid by 10 times. CAU-10-H (b) is obtained after washing. In order to improve the water vapor adsorption performance of pure CAU-10-H (b), lithium chloride (LiCl) solution was compounded with CAU-10-H (b) by impregnation method to obtain a composite adsorbent CAU-10-H (L) and its adsorption characteristics were studied. The results showed that the composite adsorbent showed good adsorption and desorption performance under test conditions. Among them, the equilibrium adsorption capacity of the composite adsorbent with 33.1% LiCl content is 0.5007 g/g after 30 cycles, which is about 1.675 times of the adsorption capacity of pure CAU-10-H (b) under the same conditions. This shows the potential of the composite adsorbent to be used in the air-water extraction system.

Effect of Low Concentrations of Lithium Chloride Additive on Cellulose-Rich Ultrafiltration Membrane Performance

Various water treatment processes make extensive use of porous polymeric membranes. A key objective in membrane fabrication is to improve membrane selectivity without sacrificing other properties such as permeability. Herein, LiCl (0-2 wt.%) was utilised as a preforming agent in fabricating biomass-derived cellulosic membranes. The fabricated membranes were characterised by dope solution viscosity, surface and cross-sectional morphology, pure water flux, relative molecular mass cut-off (MWCO, 35 kDa), membrane chemistry, and hydrophilicity. The results demonstrated that at the optimum LiCl concentration (0.4 wt.%), there is an interplay of thermodynamic instability and kinetic effects during membrane formation, wherein the membrane morphology and hydrophilicity can be preferably altered and thus lead to the formation of the membrane with better rejection at no detriment to its permeability.

Sustainable Synthesis of Iron-Zinc Nanocomposites by Azadirachta indica Leaves Extract for RSM-Optimized Sono-Adsorptive Removal of Crystal Violet Dye.

Environmental pollution has exacerbated the availability of clean water to mankind. In this study, Azadirachta indica leaf extract was used for sustainable synthesis of Fe-Zn nanocomposites (IZNC). The instrumental techniques of Fourier transformed infrared (FTIR) spectroscopy, energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to determine the structural and chemical composition. The overall surface was mildly acidic in nature, as the pHPZC was observed to be 6.00. The ultrasonicated adsorption experiments were designed by central composite design (CCD). The best responses, which proposed a contaminants removal of 80.39%, were assessed using the response surface methodology (RSM). By repeating experimental runs at the expected optimum operating parameters (OOP), the method was experimentally affirmed with the %mean error and %RSD9 being 2.695% and 1.648%, respectively. The interaction of CV dye and the nanocomposite showed tremendous adsorption efficiency towards crystal violet (CV) dye, as revealed by isotherm studies. Fitting kinetics and isotherm models were affirmed by root mean square error (RMSE), χ2, and a Pearson regression coefficient. Thermodynamic studies proved spontaneity of the CV dye adsorption over the nanocomposites. The values for ΔGo, ΔHo, and ΔSo were observed to be -1.089 kJ/mol, 28.59 kJ/mol, and -3.546 kJ/mol, respectively. Recovery of CV dye was carried out in a variety of media, including NaOH, NaCl, and CH3COOH. The maximum CV recovery was achieved in an acidic media. The robustness of adsorption was affirmed by the interference of various matrix ions, including KCl, LiCl, NaCl, and MgCl2, which did not significantly affect the adsorption process. The maximum adsorption capacity was obtained at a low concentration of LiCl. The results show that a green synthesis approach for nanocomposite synthesis might be an effective and economical way to remove organic contaminants from wastewater. Moreover, it is also effective for effluent treatment plants (ETP) for waste management purposes, in which it may be coupled with chlorine as a disinfectant to purify water that can be used for domestic and irrigation purposes.

Direct electrochemical extraction of metallic Li from a molecular liquid–Based electrolyte under ambient conditions

The high chemical activity of metallic Li hinders its efficient electrochemical extraction at low temperatures, necessitating the use of energy- and cost-intensive methods such as vacuum thermal reduction or electrodeposition from ionic-liquid and molten-salt electrolytes. Herein, we report the direct room-temperature electrowinning of metallic Li from a simple low-cost electrolyte, namely a solution of LiCl in dimethylacetamide (DMAc), determine the optimal concentration of LiCl, and examine the redox processes in the optimized system. Potentiostatic deposition on high-purity Al is shown to induce solid-state cathode alloying and thus produce a uniform, flat, and dense coating of a LiAl master alloy comprising spherical clusters formed by LiAl alloy nanosheets. Finally, the direct smelting of electrodeposited films is proposed as a method of rapidly realizing the “thin film” to “bulk” transformation of electrodeposited materials to stabilize metallic Li and form bulk Li-based alloys. Thus, this study provides a basis for the continuous, low-cost, sustainable, and fast electrochemical production of bulk active metals or their alloys.

Correlation of solute diffusion with dynamic viscosity in lithium salt-added (choline chloride + glycerol) deep eutectic solvents.

Due to their favorable physicochemical properties, deep eutectic solvents (DESs) are finding increased use in chemistry. Metal salt-added DESs are currently being investigated for their potential applications in electrochemistry as a replacement for organic electrolytes. Insights into solute diffusion in salt-added DESs, in this context, are of the utmost importance. Solute diffusion in a LiCl-added DES composed of the H-bond acceptor choline chloride and the H-bond donor glycerol in a 1 : 2 mole ratio, named glyceline, is assessed as a function of temperature and LiCl concentration. For relative translational diffusion, the fluorophore-quencher pair of pyrene-nitromethane is used, whereas for rotational diffusion a fluorescent anisotropic rotor, perylene, is selected. The fluorescence quenching of pyrene by nitromethane was found to be purely dynamic in nature. The estimated bimolecular quenching rate constant (kq) exhibits excellent adherence to the Stokes-Einstein relation, suggesting relative translational diffusion of the solute to be controlled by the dynamic viscosity of the LiCl-added glyceline solution. The rotational reorientation time (θ) of the rotor perylene is also found to scale with dynamic viscosity and obey the Stokes-Einstein relation satisfactorily. Linear correlation between θ and dynamic viscosity (η) improves for glyceline solutions with fixed LiCl concentrations hinting at the possible change in the hydrodynamic volume with LiCl concentration within the DES. Control of rotational diffusion of the solute by the dynamic viscosity is established nonetheless. The effect of earlier reported micro- and/or nano-heterogeneities within salt-added DES systems on solute diffusion dynamics is found to be minimal. The work highlights DESs in offering a solubilizing medium for solutes where the diffusion dynamics are simply controlled by the dynamic viscosity.

High Electrical Conductivity and Low Temperature Resistant Double Network Hydrogel Ionic Conductor as a Flexible Sensor and Quasi‐Solid Electrolyte

AbstractThe existence of large amounts of water in hydrogel electrolytes makes them inevitably freeze at low temperatures, which causes them to lose properties such as flexibility or electrical conductivity. It limits the application of hydrogel electrolytes at low temperatures. Here, we designed hydrogels with interpenetrating double network structure based on polyacrylamide and agar. By doping a high concentration of LiCl as the conducting material, a continuous ion‐conducting path was formed. The conductivity reached 2.18 S/m at 25 °C and 1.58 S/m at −30 °C. The prepared hydrogel electrolytes exhibit good mechanical and electrochemical properties to meet the needs of different application situations. A wearable sensor with hydrogel electrolytes was demonstrated. The wearable sensor can be attached to a part of the human body and can successfully detect various human movements. The wearable sensors can be used as temperature sensors in addition to detecting motion, which shows an encouraging and powerful utility in wearable electronic devices.

Construction of the lithium binding peptide displayed recombinant Escherichia coli for the specific lithium removal from various metal polluted wastewater

Considering the immense increase of lithium battery use, the development of efficient and environmentally friendly lithium recovering process is required. Here, we demonstrate a novel strategy for lithium extraction from battery-polluted water using a biosorbent consisting of whole cells displaying a lithium-binding peptide (LBP). For this goal, the surface of Escherichia coli was engineered to display the lithium binding peptide GPGAP (LBP) by using OmpC as an anchoring motif. Further, the lithium binding capacity of the peptide LBP was increased by construct dimers, trimers, and tetramers of LBP. The trimeric construct of LBP exhibited the highest level of lithium adsorption (3240.187 µmol g DCW−1) at 20 mM of LiCl concentration. The trimeric construct of LBP displayed E. coli showed high lithium selectivity over cobalt, chromium, and copper respectively present in artificially wastewater. When the purified lithium battery polluted wastewater through the recombinant strain was used for the growth of plants, normal growth of plant was observed while significant growth inhibition was observed in wastewater watered plant. The method developed in this study opens up a new path for the bioremediation of wastewater based on the design of synthetic peptides and their expression on microbial surfaces.

CrosslinkedPMIAultrafiltration membrane with enhanced permeability via incorporatingTMCmonomer

AbstractA trade‐off behavior is noteworthy between protein rejection and pure water flux (PWF) for ultrafiltration membranes; it is recommendable to increase flux without reducing selectivity. The poly (meta‐phenylene isophthalamide) (PMIA) ultrafiltration membrane was modified via incorporating 1,3,5‐benzene tricarboxylic chloride (TMC) to optimize the performance for the first time. Molecular dynamics (MD) simulation was applied to probe the mechanism of the effects of the concentrations of cosolvent LiCl and addition TMC on the dissolving process. It was turned out that a suitable concentration of TMC in the dope solution markedly enhanced the PWF (from 276.22 to 566.20 m−2 h−1 bar−1) with an increasing bovine serum albumin rejection (from 92.05% to 94.64%). Besides, the optimized membrane also possesses excellent anti‐fouling and mechanical performance. These improvements can be due to the crosslinking between PMIA and TMC and enlarged average pore diameter. This work broadens the application of PMIA and TMC in ultrafiltration and provides a novel methodology for PMIA modification.

Separation of essential oil from fresh leaves of Phellodendron amurense rupr. By solvent-free microwave-assisted distillation with the addition of lithium salts

The essential oil was separated from the fresh leaves of Phellodendron amurense Rupr. by solvent-free microwave-assisted distillation in a rotating state with n-hexane extraction and LiCl addition, which ingeniously designed lithium salt addition, rotation unit, and n-hexane extraction effectively improved the yield and separation rate of essential oils. The factors that may affect essential oils yield were screened and optimized by single factor optimization, response surface methodology, and kinetic model to obtain the optimal conditions for the separation of essential oils by this method, which were LiCl content of 8%FW, microwave irradiation power 600 W and microwave irradiation time 40 min. And the yield of essential oils is 2.39 ± 0.12 mg/g in the optimum conditions by this method, which is highly consistent with the predictions from the response surface method (2.39 mg/g) and the first-order kinetic model (2.42 ± 0.04 mg/g). This method effectively ensures the uniform heating of the plant material and the rapid overflow of the essential oil by employing the rotating unit and the addition of LiCl, which effectively avoids the loss of the heat-sensitive components in the essential oil. Moreover, the solvent-free distillation of this method highly improves the heating rate, and the added LiCl can also be effectively recovered and reused, which effectively reduces the economic cost, and environmental stress and will result in a cleaner product. And an accurate quantitative analysis method of essential oils was established by n-hexane extraction-ultraviolet spectroscopy, which not only effectively avoided the loss of water-soluble components but also provided a new strategy for quantitative analysis of essential oils. In addition, the results of the kinetic model indicated that the separation rate constant of essential oils in this method was 1.34 times that of microwave-assisted hydrodistillation and 5.05 times that of conventional hydrodistillation. Therefore, this method is an efficient, green, and clean essential oil preparation method, which is very promising to replace existing methods in the future.

Techno-Economic Analysis of Atmospheric Water Generation by Hybrid Nanofluids to Mitigate Global Water Scarcity

Globally, multiple efforts are being made to develop active atmospheric water generation (AWG) or atmospheric water extraction (AWE) systems, particularly using direct air-cooling technology to produce water from ambient air. However, this legacy technique is highly energy-intensive; it can only be operated when the local dew point is above the freezing point of water, and does not scale to create enough water to offer solutions for most industries, services, or agriculture. Liquid-desiccant-based AWG methods show promising performance advantages, and offer a versatile approach to help address the thermodynamics, health risks, and geographic constraints currently encountered by conventional active AWG systems. In this study, we performed a techno-economic analysis of a liquid-desiccant-based AWG system with a continuous operating style. An energy balance was performed on a single design point of the AWG system configuration while using a LiCl liquid desiccant loaded with multiwalled carbon nanotubes (MWCNTs). We showed that the MWCNTs can be doped in LiCl for effective heat transfer during water desorption, resulting in lowering of the sensible heat load by ≈49% on the AWG system. We demonstrated that the specific energy consumption (SEC) can currently be obtained as low as 0.67 kWh per US gallon, while changing the inlet desiccant stream concentration of MWCNT-doped LiCl under the given conditions. While the production cost of water (COW) showed a significant regional dependency, economic analysis revealed that water can be produced at a minimum selling price of USD 0.085 per US gallon, based on the 2021 annual average wholesale electricity cost of USD 0.125 per kWh in the U.S.A., thereby providing a strong foundation for future research to meet desirable and competitive water costs by 2026, but before 2031.

Assessment of dehumidification performance of non-corrosive desiccant in hybrid liquid desiccant-vapour compression system

ABSTRACT Air-conditioning (AC) systems, which operate on traditional vapor compression refrigeration (VCR) systems, consume a substantial proportion of the world’s electricity consumed by the building industry. In the scope of decreasing greenhouse gas emissions, energy consumption, heating, ventilation, and air conditioning industries have focused on finding alternatives to electrically operated VCR systems. A combination of a liquid desiccant dehumidification system (LDDS) with a VCR system has been recommended as a superior substitute in warm and moist climates. The focus of this research article is to design and fabricate a small-scale 5 kW hybrid LDDS system by integrating the distinct technologies mentioned above. Additionally, data collected on the vapor pressure of potassium formate (KCOOH) at various solution concentrations and temperatures is being collected to assist in encouraging research and determine the optimal concentration range. In this study, experimental analysis and comparison of dehumidification performance was conducted between two desiccants by analyzing the effects of input variables ( m a , T d , and ω s ) on the output response ( Δ ω , Q d e h , and C O P h ). The results showed that the solution with a 69.92% KCOOH concentration had nearly the same vapor pressure as a solution with a 35% LiCl concentration. Moreover, it was revealed that the lowest values of m a and T d and the highest value of ω s yield maximum values of the output responses. At the same combination of input variables, the KCOOH desiccant has a much higher hybrid system coefficient of performance than the LiCl desiccant.

Lithium chloride leads to concentration dependent brood damages in honey bee hives (Apis mellifera) during control of the mite Varroa destructor

Lithium chloride (LiCl) has a high efficacy against Varroa destructor and a good tolerability for adult bees but the effect of LiCl on the honey bee brood has not been taken into consideration yet. We quantified the mortality of larvae fed with different concentrations of LiCl. For artificially reared larvae already, a concentration of 1 mM had significant toxic effects while under colony conditions, 10 mM was well tolerated. However, a chronic application of the effective concentration of 25 mM elicited brood mortalities between 60 and 90%. Shorter feeding periods of 2 or 4 days reduced the brood damages significantly. Measurements of the lithium concentrations in larvae and pupae during a chronic exposure with 10, 17.5 and 25 mM LiCl revealed respective lithium levels in 5th instar larvae of 7, 13 and 15 mg/kg. No lithium was detectable in 2-day old larvae indicating that pure worker jelly from the hypopharyngeal gland is not contaminated with LiCl. Based on these results, applications of LiCl in colonies with brood should be avoided.

CHITIN HYDROGEL PREPARED AT VARIOUS TEMPERATURE OF WATER VAPOR–INDUCED PHASE INVERSION

"Chitin solutions were obtained by dissolving chitin extracted from crab shell waste in N,N-dimethylacetamide (DMAc) solvent, in the presence of 5, 7 and 10% lithium chloride (LiCl). Then, the concentrated chitin solution was subjected to water vapor-induced phase inversion to prepare the chitin hydrogel. The properties of the resultant chitin hydrogel having various LiCl concentrations were determined after coagulating at different temperatures of the water vapor, namely, 5, 20 and 60 °C. The viscosity of the chitin solutions decreased when the temperature increased, suggesting the formation of the hydrogel could be accelerated by applying heat. After the chitin solution was coagulated, the resultant hydrogels prepared at higher temperature of water vapor provided better properties than those of the others. When the concentration of LiCl in the hydrogel was 7%, the water content values decreased from 407 to 359%, and the tensile strength increased from 447 to 737 kPa as the temperature was adjusted from 5 to 60 °C, respectively. As for viscoelasticity, the storage modulus of the chitin hydrogels indicated that the increment in the LiCl concentration to 7% and the water-vapor temperature of 60 °C could form a tighter structure of the hydrogels. Considering the green preparation route of the chitin hydrogels and their obtained characteristics, they can be considered as promising materials for applications where such properties required, such as in the biomedical and agricultural sectors."

Evaluation of performance properties of poly(styrene‐co‐butadiene) rubber reinforced with N,N‐Dimethylacetamide/lithium chloride treated precipitated silica

AbstractPrecipitated silica, treated with N,N‐Dimethylacetamide (DMAc)/Lithium Chloride (LiCl) at different LiCl concentrations, is used as reinforcing filler for poly(styrene‐co‐butadiene) rubber (SBR). DMAc/LiCl treatment of silica reduces hydrogen bonding within silica particles and improve its dispersion in rubber. Fourier transform‐infrared spectroscopy (FTIR) and X‐ray diffraction (XRD) data of treated DMAc/LiCl silica have indicated increased free hydroxyl groups as LiCl concentration in DMAc increases. Scanning electron microscopy (SEM) and Atomic force microscopy (AFM) investigations revealed smaller silica agglomerates, reduced scan height distribution and surface roughness. Better dispersion and reduced storage hardening of DMAc/LiCl treated silica‐filled SBR masterbatches, in the presence of bis‐(triethoxy silylpropyl)‐tetrasulphide (TESPT), are indications of easier processing of these compounds as observed from Mooney viscosity data. Mooney scorch time values at 125°C for compounds containing treated silica have indicated increased cure rates. Moving die rheometer data at 150°C have shown that combination of TESPT and DMAc/LiCl enhanced the processing safety of SBR compounds. Optimum concentration of LiCl combined with TESPT has resulted in enhanced crosslink density, physical properties, reduced swelling and heat build‐up in SBR vulcanizates.

Optimization of LiCl concentration on polyaniline composites for symmetric and asymmetric supercapacitor devices

Polyaniline doped lithium chloride (PANI-LC (1–7)) composites are synthesized via the in-situ chemical oxidative method by varying the Lithium Chloride (LC) concentrations from 0.0625 to 3 M for symmetric and asymmetric supercapacitor applications. The resultant composites are characterized through Thermogravimetric analysis and X-ray photoelectron spectroscopy. In addition they were subjected to electrochemical measurements such as cyclic voltammetry, galvanostatic charge-discharge, and impedance spectroscopy measurements. Because of its high specific capacitance and excellent capacitance retention, PANI-LC 6 composite is used to fabricate symmetric and asymmetric supercapacitors. The highest specific capacitance of 388 Fg−1 at a scan rate of 1 mV s−1 and 375 Fg−1 at a current density of 1 Ag−1 in 1 M H2SO4 is obtained for PANI-LC 6 composite. Maximum specific capacitance of 89 Fg–1 (symmetric device) and 60 Fg–1 (asymmetric device) is achieved at a current density of 2 Ag–1. Symmetric and asymmetric devices deliver the maximum energy density of 12.3 Whkg−1 and 16.4 Whkg−1 at a power density of 289 W kg−1 and 71.8 W kg−1, respectively.

One-pot synthesis of anti-freezing carrageenan/polyacrylamide double-network hydrogel electrolyte for low-temperature flexible supercapacitors

Stretchable carrageenan (CG) based double-network (DN) hydrogel has great potential in flexible energy storage devices. To achieve high conductivity at sub-zero temperatures, one-pot synthesis method is adopted for the fabrication of CG/polyacrylamide DN hydrogel with high LiCl concentration (termed CG/PAAm-xLi). In this method, a high temperature above 90 °C is required to fully melt CG network in the presence of high-concentration LiCl and to add the monomers of the second polymer network. Furthermore, by incorporation of small amounts of KCl, the obtained CG/PAAm-7Li/K DN hydrogel shows strong tensile properties with tensile elongation of 567.7%, and fracture energy of 967.3 kJ/m2. In addition, the conductivity of the CG/PAAm-7Li/K DN hydrogel achieves 1.9 S/m at − 40 °C. The flexible supercapacitor prepared by using CG/PAAm-7Li/K hydrogel electrolyte exhibits excellent low-temperature electrochemical properties (specific capacitance of 73.4 F/g, and capacitance retention of 95.6% after 20,000 cycles at − 40 °C). This high-temperature strategy may be extended to construct other ionic polysaccharide-based hydrogel electrolytes with high mechanical property and excellent low-temperature electrochemical performance, showing a broad prospect in the field of flexible electronics.