Biopolymer electrolyte from banana powder-konjac glucomannan for zinc-ion batteries

Herein, the novel eco-friendly biopolymer electrolytes consisting of banana powder and konjac glucomannan host matrix doped with zinc acetate salt were successfully fabricated through simple casting technique. The biopolymer electrolyte exhibited satisfactory thermal stability and mechanical properties; tensile strength (13.82 MPa); elongation at break (60.52 %) and Young's modulus (93.2 MPa). The electrochemical studies were carried out in symmetrical cells Zn/Zn cells. Biopolymer electrolyte showed favorable ionic conductivity of 5.59 × 10-4 S/cm along with stable cycling performance. The potential stability was found to be 2.52 V. The as-prepared biopolymer electrolytes demonstrated the potential as green, simple yet effective biopolymer electrolytes for zinc-ion batteries.

Deciphering the Effect of Microstructural Modification in Sodium Alginate-Based Solid Polymer Electrolyte by Unlike Anions

Microstructure modification in sodium alginate (NaAlg)-based solid polymer electrolytes by the perchlorate (ClO4-) and acetate (CH3COO-) anions of sodium salts has been reported. ClO4- participates in the structure-breaking effect via inter/intramolecular hydrogen bond breaking, while CH3COO- changes the amorphous phase, as evident from X-ray diffraction studies. The larger size and negative charge delocalization of ClO4- have a plasticizing effect, resulting in a lower glass transition temperature (Tg) compared to CH3COO-. Decomposition temperature is strongly dependent on the type of anion. Scanning electron microscopy images showed divergent modifications in the surface morphology in both electrolyte systems, with variations in salt content. The mechanical properties of the NaAlg-NaClO4 electrolyte systems are better than those of the NaAlg-CH3 COONa system, indicating weak interactions in the latter. Although most of the studies focus on the cation influence on conductivity, the interaction of the anion and its size certainly have an influence on the properties of solid polymer electrolytes, which will be of interest in the near future for sodium ion-based electrolytes in energy storage devices.

Bigels constructed from hybrid gelator systems: bulk phase-interface stability and 3D printing

In this study, edible bigels with different ratios of beeswax-based oleogel to gellan gum-based hydrogel were developed and characterized. Gellan gum formed a 3D network in water through hydrogen bonding. Beeswax formed a crystalline network in the oil phase, which prevented the flow of oil and formed an oleogel. The position of the droplets is fixed by the crystallization of glycerol monostearate (GMS) at the interface. Bigels with different oleogel contents presented different types of O/W (oleogel content was less than 62%), semi-bicontinuous (oleogel content was 62-68%), and W/O bigels (oleogel content was more than 70%), respectively. Rheological experiments showed bigels had a shear thinning ability, which was suitable for extrusion 3D printing. Then the applicability of 3D printing was studied and it was found that the self-supporting ability of bigels became stronger with the increase of oleogel content. Functional pigments were incorporated into the bigel inks, making the 3D printing product nutrient-rich and color customizable. These results would favor guiding the preparation of bigels with adjusted physical properties and delicate structures for 3D food printing to satisfy the personal desire of consumers.

Progress and opportunities in Gellan gum-based materials: A review of preparation, characterization and emerging applications

Gellan gum, a microbial exopolysaccharide, is biodegradable and has potential to fill several key roles in many fields from food to pharmacy, biomedicine and tissue engineering. In order to improve the physicochemical and biological properties of gellan gum, some researchers take advantage of numerous hydroxyl groups and the free carboxyl present in each repeating unit. As a result, design and development of gellan-based materials have advanced significantly. The goal of this review is to provide a summary of the most recent, high-quality research trends that have used gellan gum as a polymeric component in the design of numerous cutting-edge materials with applications in various fields.

Impact of charge carrier transport properties on conductivity-temperature dependence of gellan gum-LiCF3SO3 biopolymer electrolyte

Charge carrier density, mobility and diffusivity are three important transport properties in determining the ionic conductivity as well as the performance of solid polymer electrolyte. In this work, biopolymer electrolytes samples were prepared using the solution casting method by complexing gellan gum with different concentrations of lithium trifluoromethanesulfonate (3–15 wt.%). The values of charge carrier concentration, mobility, and diffusivity for electrolyte samples were estimated by fitting the Nyquist plot with an equation developed based on electrical impedance spectroscopy. At room temperature, the optimum electrolyte conductivity is 1.29×10−8 Scm−1 at 6 wt.% salt concentration. This result was supported by the highest percentage of free ions, 31.45%, observed in the FTIR method. As the temperature increases, the ionic conductivity increases to the optimum value before dropping. The highest conductivity of each sample was obtained at different temperatures (80°C–90°C) using the impedance method, whereas the percentage area of free ions was highest at 80°C for all samples with FTIR analysis. Overall, the ionic conductivity of this system has been dominated by the carrier charge density. Results suggest that, under these experimental conditions, electrical impedance spectroscopy is suitable for evaluating the charge transport properties at low temperatures.

Solid Polymer Electrolytes Based on Gellan Gum and Ionic Liquid for Sustainable Electrochromic Devices

Materials sustainability is becoming increasingly relevant in every developed technology and, consequently, environmentally friendly solid polymer electrolytes (SPEs) based on gellan gum and different quantities of ionic liquid (IL) 1-ethyl-3-methyl-imidazolium-thiocyanate [Emim][SCN] have been prepared and applied in electrochromic devices (ECDs). The addition of the IL does not affect the crystalline phase of gellan gum, and the samples show a compact morphology, surface uniformity, no phase separation, and good distribution of the IL within the carrageenan matrix. The developed SPE are thermally stable up to ∼100 °C and show suitable mechanical properties. The most concentrated sample (39 wt % IL content) reaches a maximum ionic conductivity value of 6.0 × 10^-3 S cm^-1 and 1.8 × 10^-2 S cm^-1 at 30 and 90 °C, respectively. The electrochromic device (ECD) was fabricated with poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) as working electrode and the developed SPE was compared with an aqueous 0.1 M KNO₃ solution. The electrochromic performance of the electrolyte was assessed in terms of spectroelectrochemistry, demonstrating a fully flexible ECD operating at voltages below 1.0 V. This novel electrolyte opens the door to the preparation of high performance sustainable ECD.

Development and characterization of eco-friendly biopolymer gellan gum based electrolyte for electrochemical application

Magnesium ion conducting eco-friendly biopolymer electrolyte based on gellan gum has been developed by solution casting technique and characterized by XRD, FTIR, DSC, AC impedance analysis and LSV. Amorphous nature of the polymer electrolyte has been confirmed by XRD analysis. FTIR analysis confirms the complex formation between gellan gum and magnesium nitrate salt. Glass transition temperature of the polymer electrolytes have been found in DSC analysis. Ionic conductivity of polymer electrolyte membrane has been analysized by AC impedance studies, polymer electrolyte 1.0 g gellan gum with 0.7 wt% Mg (NO3)2 has highest ionic conductivity 1.392 × 10−2 S/cm at room temperature. Evan’s polarization method attributes Mg+ cationic transference number as 0.342 for high conducting polymer electrolyte. The high conducting polymer membrane has electrochemical stability 3.58 V. Using this high conducting polymer electrolyte, magnesium ion battery is constructed and the battery performance was studied. The open circuit voltage is found as 1.99 V.

Development on Solid Polymer Electrolytes for Electrochemical Devices

Electrochemical devices, especially energy storage, have been around for many decades. Liquid electrolytes (LEs), which are known for their volatility and flammability, are mostly used in the fabrication of the devices. Dye-sensitized solar cells (DSSCs) and quantum dot sensitized solar cells (QDSSCs) are also using electrochemical reaction to operate. Following the demand for green and safer energy sources to replace fossil energy, this has raised the research interest in solid-state electrochemical devices. Solid polymer electrolytes (SPEs) are among the candidates to replace the LEs. Hence, understanding the mechanism of ions' transport in SPEs is crucial to achieve similar, if not better, performance to that of LEs. In this paper, the development of SPE from basic construction to electrolyte optimization, which includes polymer blending and adding various types of additives, such as plasticizers and fillers, is discussed.

Effect of new crystalline phase on the ionic conduction properties of sodium perchlorate salt doped carboxymethyl cellulose biopolymer electrolyte films

Dopant induced modifications in the microstructure of sodium carboxymethyl cellulose (NaCMC) were characterized by FTIR, XRD, DSC and EIS techniques. FTIR analysis exhibited a considerable microstructural modification in NaCMC upon NaClO4⋅H2O doping invoked through complex formation via Lewis acid-base interaction and hydrogen bond formation between ions and dipoles. This resulted in the modification in the orderliness/disorderliness of polymer chains as observed from XRD deconvolution. At higher salt concentrations, the complexity of the network causes the formation of new amorphous and crystalline phases as reflected in the XRD studies. DSC analysis showed an increase in Tg as the salt concentration increased, indicating a reduction in polymer chains flexibility. The contribution of free ions has masked over the enhancement in amorphous content to conductivity at a lower concentration of salt in the matrix, later on, the formation of a new crystalline phase due to transient crosslinks by Na+…ClO4−…Na+ has affected the ion transport process.