Design of non-faradaic EDLC from plasticized MC based polymer electrolyte with an energy density close to lead-acid batteries

Datura metel L. leaf extract mediated sodium alginate polymer membrane for supercapacitor and food packaging applications

Datura metel L. leaf extract mediated sodium alginate polymer membrane was successfully made using the solution casting technique. Electric, electrochemical, physicochemical and antimicrobial analyses of the prepared film were investigated. Functional groups of polysaccharides are identified in FTIR analysis and crystallinity/amorphous of the prepared samples was studied using XRD analysis. The prepared polymer membrane (DmMSA2) exhibits the ionic conductivity of 2.18 × 10^-4 Scm^-1, maximum specific capacitance of 131 F/g at a current density of 0.2 A/g and also exhibits a significant effect of antimicrobial activity against human pathogens. Hence, Datura metel L. leaf extract mediated polymer membranes are promising candidates for solid-electrolyte in supercapacitor devices and antimicrobial agents in food packaging applications.

Facile synthesis of the SnTe/SnSe binary nanocomposite via a hydrothermal route for flexible solid-state supercapacitors

Environmental degradation and energy shortage are the two biggest problems facing the world right now. Because of the limited supply of non-renewable sources, the production of environment-friendly energy and its storage has gained significant importance. Pseudocapacitors have lately caught the interest of energy specialists due to their greater energy/power density and prolonged cycle life. In this work, binding-free SnTe/SnSe (STSS) electrodes deposited onto Ni foam (NF) as the conductive substrate have been developed by a facile hydrothermal route for supercapacitor applications. Several analytical tools were utilized to study the morphological, structural and textural characteristics. The electrochemical results obtained from a three-electrode system suggest that the STSS electrode material exhibits great specific capacitance (C _s) of 1276 F g^-1, specific energy (E _d) of 46.45 W h kg^-1 and specific power (P _d) of 256 W kg^-1 @ 1 A g^-1. The results of C _dl indicate that the STSS (31.28 mF) has a larger C _dl value than those of SnTe (23.22 mF) and SnSe (26.35 mF). The analysis of electrochemical stability indicates that the STSS displays structural stability over 5000 cycles with a maximum capacitance retention of 96%. The Nyquist plot profile displayed a smaller R _ct value for STSS (0.89 Ω) than SnSe (1.13 Ω) and SnTe (1.97 Ω). The symmetric behavior of STSS was determined in 2.0 M potassium hydroxide. The results reveal that this material has a specific capacitance of 537.72 F g^-1 and specific energy of 78.32 W h kg^-1. These findings suggest that the STSS electrode might serve as a potential candidate for supercapacitors and other energy-saving equipment.

Characteristics of Methyl Cellulose Based Solid Polymer Electrolyte Inserted with Potassium Thiocyanate as K+ Cation Provider: Structural and Electrical Studies

The attention to a stable and ionic conductive electrolyte is driven by the limitations of liquid electrolytes, particularly evaporation and leakage, which restrain their widespread use for electrochemical device applications. Solid polymer electrolyte (SPE) is considered to be a potential alternative since it possesses high safety compared to its counterparts. However, it still suffers from low device efficiency due to an incomplete understanding of the mechanism of ion transport parameters. Here, we present a simple in situ solution casting method for the production of polymer-based electrolytes using abundantly available methylcellulose (MC) doped at different weight percentages of potassium thiocyanate (KSCN) salt. Fourier transform infrared (FTIR), and electrochemical impedance spectroscopy (EIS) methods were used to characterize the prepared samples. Based on EIS simulation and FTIR deconvolution associated with the SCN anion peak, various ion transport parameters were determined. The host MC medium and KSCN salt have a strong interaction, which was evident from both peak shifting and intensity alteration of FTIR spectra. From the EIS modeling, desired electric circuits correlated with ion movement and chain polarization were drawn. The highest ionic conductivity of 1.54 × 10^-7 S cm^-1 is determined from the fitted EIS curve for the film doped with 30 wt.% of KSCN salt. From the FTIR deconvoluted peak, free ions, ions in contact with one another, and ion aggregates were separated. The extracted ion transport parameters from the EIS method and FTIR spectra of the SCN anion band confirm that both increased carrier concentration and their mobility were crucial in improving the overall conductivity of the electrolyte. The dielectric investigations were further used to understand the conductivity of the films. High dielectric constants were observed at low frequencies for all MC:KSCN systems. The dispersion with a high dielectric constant in the low-frequency band is ascribed to the dielectric polarization. The wide shift of M″ peak towards the high frequency was evidenced by the MC-based electrolyte impregnated with 30 wt.% of KSCN salt, revealing the improved ionic movement assisted with chain segmental motion. The AC conductivity pattern was influenced by salt concentration.

Study of MC:DN-Based Biopolymer Blend Electrolytes with Inserted Zn-Metal Complex for Energy Storage Devices with Improved Electrochemical Performance

Stable and ionic conducting electrolytes are needed to make supercapacitors more feasible, because liquid electrolytes have leakage problems and easily undergo solvent evaporation. Polymer-based electrolytes meet the criteria, yet they lack good efficiency due to limited segmental motion. Since metal complexes have crosslinking centers that can be coordinated with the polymer segments, they are regarded as an adequate method to improve the performance of the polymer-based electrolytes. To prepare plasticized proton conducting polymer composite (PPC), a simple and successful process was used. Using a solution casting process, methylcellulose and dextran were blended and impregnated with ammonium thiocyanate and zinc metal complex. A range of electrochemical techniques were used to analyze the PPC, including transference number measurement (TNM), linear sweep voltammetry (LSV), cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The ionic conductivity of the prepared system was found to be 3.59 × 10^-3 S/cm using the EIS method. The use of glycerol plasticizer improves the transport characteristics, according to the findings. The carrier species is found to have ionic mobility of 5.77 × 10^-5 cm² V^-1 s^-1 and diffusion coefficient of 1.48 × 10^-6 cm² s^-1 for the carrier density 3.4 × 10²⁰ cm^-3. The TNM revealed that anions and cations were the predominant carriers in electrolyte systems, with an ionic transference value of 0.972. The LSV approach demonstrated that, up to 2.05 V, the film was stable, which is sufficient for energy device applications. The prepared PPC was used to create an electrical double-layer capacitor (EDLC) device. The CV plot exhibited the absence of Faradaic peaks in the CV plot, making it practically have a rectangular form. Using the GCD experiment, the EDLC exhibited low equivalence series resistance of only 65 Ω at the first cycle. The average energy density, power density, and specific capacitance values were determined to be 15 Wh/kg, 350 W/kg, and 128 F/g, respectively.

Fabrication and Model Characterization of the Electrical Conductivity of PVA/PPy/rGO Nanocomposite

Owing to the numerous advantages of graphene-based polymer nanocomposite, this study is focused on the fabrication of the hybrid of polyvinyl alcohol (PVA), polypyrrole (PPy), and reduced graphene-oxide. The study primarily carried out the experimentation and the mathematical analysis of the electrical conductivity of PVA/PPy/rGO nanocomposite. The preparation method involves solvent/drying blending method. Scanning electron microscopy was used to observe the morphology of the nanocomposite. The electrical conductivity of the fabricated PVA/PPy/rGO nanocomposite was investigated by varying the content of PPy/rGO on PVA. From the result obtained, it was observed that at about 0.4 (wt%) of the filler content, the nanocomposite experienced continuous conduction. In addition, Ondracek, Dalmas s-shape, dose–response, and Gaussian fitting models were engaged for the analysis of the electrical transport property of the nanocomposite. The models were validated by comparing their predictions with the experimental measurements. The results obtained showed consistency with the experimental data. Moreover, this study confirmed that the electrical conductivity of polymer-composite largely depends on the weight fraction of fillers. By considering the flexibility, simplicity, and versatility of the studied models, this study suggests their deployment for the optimal characterization/simulation tools for the prediction of the electrical conductivity of polymer-composites.

Ultrastable Conjugated Microporous Polymers Containing Benzobisthiadiazole and Pyrene Building Blocks for Energy Storage Applications

In recent years, conjugated microporous polymers (CMPs) have become important precursors for environmental and energy applications, compared with inorganic electrode materials, due to their ease of preparation, facile charge storage process, π-conjugated structures, relatively high thermal and chemical stability, abundance in nature, and high surface areas. Therefore, in this study, we designed and prepared new benzobisthiadiazole (BBT)-linked CMPs (BBT-CMPs) using a simple Sonogashira couplings reaction by reaction of 4,8-dibromobenzo(1,2-c;4,5-c')bis(1,2,5)thiadiazole (BBT-Br2) with ethynyl derivatives of triphenylamine (TPA-T), pyrene (Py-T), and tetraphenylethene (TPE-T), respectively, to afford TPA-BBT-CMP, Py-BBT-CMP, and TPE-BBT-CMP. The chemical structure and properties of BBT-CMPs such as surface areas, pore size, surface morphologies, and thermal stability using different measurements were discussed in detail. Among the studied BBT-CMPs, we revealed that TPE-BBT-CMP displayed high degradation temperature, up to 340 °C, with high char yield and regular, aggregated sphere based on thermogravimetric analysis (TGA) and scanning electron microscopy (SEM), respectively. Furthermore, the Py-BBT-CMP as organic electrode showed an outstanding specific capacitance of 228 F g-1 and superior capacitance stability of 93.2% (over 2000 cycles). Based on theoretical results, an important role of BBT-CMPs, due to their electronic structure, was revealed to be enhancing the charge storage. Furthermore, all three CMP polymers featured a high conjugation system, leading to improved electron conduction and small bandgaps.