Solid Biopolymer Electrolytes Research Articles

Structural investigation of solid biopolymer electrolytes: 2-hydroxyethyl cellulose doped ammonium formate as a promising proton conductor

Fabrication of solid biopolymer electrolytes (SBEs) was mainly to cater the drawbacks of lithium-ion electrolytes in terms of leakage, high cost, and toxic material. In this present work, solid biopolymer electrolytes system comprises of 2-Hydroxyethyl Cellulose (2-HEC) as polymer host, and various weight percentage (wt.%) of Ammonium Formate (AF) as ionic doping salt are produced by using solution casting technique. The relation between structural and ionic conductivity of 2-HEC/AF was analyzed and investigated by using X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Electrical Impedance Spectroscopy (EIS). Through the analysis of XRD, it can be observed that the amorphous region of SBEs increases as the concentration of AF salt increases. The amorphous region of SBEs can be confirmed due to the interaction of salt concentration and polymer. However, in this present work, the broadest peak in XRD of the sample does not necessarily correlate with the highest conductivity among the samples. The interaction between polymer-salt complexes is proved through FTIR spectrum at the range of 700 cm−1 to 1300 cm−1. The highest ionic conductivity of 2-HEC/AF achieved is 2.40 × 10−3 S/cm at room temperature for SBEs containing 40 wt.% of AF. The findings from this study made it clear that the concentration of Ammonium Formate salt affects the increase in ionic conductivity.

Synergistic Blends of Sodium Alginate and Pectin Biopolymer Hosts as Conducting Electrolytes for Electrochemical Applications.

The world needs sustainable energy resources with affordable, economic, and accountable sources. Consequently, energy innovation technologies are evolving toward electrochemical applications like batteries, supercapacitors, etc. The current study involves the solid blend biopolymer electrolyte (SBBE) with different compositions of sodium alginate blended with pectin via the casting technique. The characterization of the sample was tested by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, AC impedance, linear sweep voltammetry (LSV), and cyclic voltammetry (CV) analyses. Evidently, the sample NP4 (NaAlg/pectin = 60:40 wt %) has a higher conductivity of 1.26 × 10-7 and 3.25 × 10-6 S cm-1 at 303 and 353 K, respectively. The performances of the samples were analyzed with variations in temperature, frequency, and time responses to signify the blended nature of the electrolyte. Hence, the studied biopolymers can be constructed for electrochemical device applications.

Crystal structure, Hirshfeld surface analysis and ionic conduction properties of 4-(diphenylamino)benzaldehyde-4-(methyl)thiosemicarbazone additive with D-π-D molecular arrangement system

A new single crystal of 4-(diphenylamino)benzaldehyde-4-(methyl)thiosemicarbazone, featuring a D-π-D molecular template was synthesized and utilized as an additive in solid biopolymer electrolytes mixed with carboxymethyl cellulose (CMC) and propylene carbonate (PC). The additive was structurally characterized using single-crystal X-ray diffraction. This revealed a triclinic crystal structure belonging to the triclinic space group, P1−. The lattice parameters were determined as follows: a = 6.942(6) Å; b = 11.409(11) Å; c = 12.442(10) Å; α= 91.024(16)°; β= 104.264(12)°; γ= 107.496(12)°; V= 906.4(13)Å3 and Z= 2. Notably, the additive exhibited extensive π-electron delocalization, leading to the formation of infinite chains through C-H-π interactions and intermolecular hydrogen bonding, ultimately resulting in an inverse centrosymmetric dimer in the form of the R22(8) motif. Furthermore, a detailed Hirshfeld surface analysis of the additive revealed significant contributions from C···H/ H···C, H···S/S···H and H···N/ N···H interactions with 20.7%, 11.2% and 3.7% of the total Hirshfeld surface analysis, respectively. These interactions indicate the potential of the additive to facilitate efficient electron transfer processes. The conductivity (σ) of the CMC–PC–additive system determined at ambient temperature was 8.00 ×10−9 Scm−1. The dielectric properties showed that the system follows the non-Debye behavior, in which the conductivity is predominantly due to ion conduction via the hopping mechanism.

A response surface methodology approach to crafting superior performance of potassium salt-based solid biopolymer electrolytes

In this study, we developed an eco-friendly solid electrolyte by blending pectin (PT) with methylcellulose (MC) and complexed with potassium carbonate (K2CO3) salt and ethylene carbonate (EC) plasticizer. The goal of the study was to understand the salt-plasticizer interaction and to optimize the electrochemical performance using response surface methodology (RSM) within the central composite design (CCD). RSM approach unveiled that K2CO3 and EC interact significantly, impacting the ionic conductivity and potential window of the solid biopolymer electrolytes (SBEs). After optimization, this work achieved ideal conditions with 35.05 wt% K2CO3 and 16.78 wt% EC, yielding an ionic conductivity of ∼ 1 × 10-3 Scm−1 and a 4.77 V potential window. Structural analysis confirmed coordination among constituents and increased amorphous content. This work, therefore, highlights PT/MC/K2CO3/EC's potential for electrochemical device applications. An electrochemical cell constructed using the optimized sample exhibited the highest specific capacitance of 50.74 Fg–1, as determined by cyclic voltammetry (CV) analysis.

Conductivity and electrochemical behaviour of CoFe2O4 dispersed potato starch-based solid biopolymer electrolyte for energy application

Conductivity and electrochemical behaviour of CoFe2O4 dispersed potato starch-based solid biopolymer electrolyte for energy application

Effect of Lithium Salts on the Properties of Cassava Starch Solid Biopolymer Electrolytes.

This study evaluates the effect of lithium salts on the structural, electrochemical, and thermal properties of cassava starch solid biopolymer electrolytes (SBPEs). Films of SBPEs were synthesized using plasticizing agents and lithium salts (LiCl, Li2SO4, and CF3LiSO3) via thermochemical method. The SBPEs with lithium salts exhibited characteristic FTIR bands starch, with slight variations in the vibration oxygen-related functional groups compared to salt-free biopolymer spectra. The RCOH/COC index (short-range crystallinity) was higher in the films synthesized without lithium salt and the lowest value was established in the films synthesized with Li2SO4. Thermal degradation involved dehydration between 40 to 110 °C and molecular decomposition between 245 to 335 °C. Degradation temperatures were close when synthesized with salts but differed in films without lithium salt. DSC revealed two endothermic processes: one around 65 °C linked to crystalline structure changes and the second at approximately 271 °C associated with glucose ring decomposition. The electrochemical behavior of the SBPEs varied with the salts used, resulting in differences in the potential and current of peaks from the redox processes and its conductivity, presenting the lowest value (8.42 × 10-5 S cm-1) in the SBPE films without salt and highest value (9.54 × 10-3 S cm-1) in the films with Li2SO4. It was concluded that the type of lithium salt used in SBPEs synthesis affected their properties. SBPEs with lithium triflate showed higher molecular ordering, thermal stability, and lower redox potentials in electrochemical processes.

The study of ion transport parameters connected with Na+ ion dynamics in biopolymer electrolytes through electrical equivalent circuits: Dielectric and electrochemical properties

Non-toxic materials including polymers and salts meet global demand for renewable energy and they are crucial to be considered in the energy storage application. In this study, the appropriateness of solid biopolymer electrolytes for energy storage applications is examined, as these materials have the potential to overcome the limitations of conventional liquid electrolytes. The solution casting method to generate membranes of ion-conducting polymer blend-based electrolytes from a methylcellulose-dextran (MC:DEX) blend mixed with sodium acetate (NaCH3COO) to act as an Na+ supply, and glycerol to serve as a plasticizer. The electrochemical impedance measurement is performed to determine several transport parameters, including density number (n), mobility (µ), and diffusion coefficient (D). The highest glycerol content resulted in an ionic conductivity of 8.87×10−5 S cm−1. Furthermore, the electrical properties of the electrolytes are investigated, including dielectric, AC conductivity and electric modulus parameters. The maximum plasticized system was found to have an ion transference number of 0.98, indicating that ions played a critical role in the charge transfer mechanisms. Linear sweep voltammetry analysis demonstrated the stability of the maximum conductive sample up to 2.3 V.

Investigation on electrical and electrochemical behaviour of cellulose acetate: Ammonium iodide: Silica composite biopolymer electrolyte for proton exchange membrane (PEM) fuel cell performance

Cellulose acetate (CA): ammonium iodide (NH4I) solid biopolymer electrolyte and cellulose acetate (CA): ammonium iodide (NH4I): silica (SiO2) particle composite-based biopolymer electrolytes were developed via solution casting route for single proton-exchange membrane fuel cells (PEMFC) applications. X-ray diffraction (XRD) analysis was used to identify the diffraction peaks and their corresponding angles, which led to the confirmation of the aforementioned biopolymer. The admixture of SiO2 into the 50CA:50NH4I improves the amorphous nature than 50CA:50NH4I in the XRD pattern. Using electrochemical impedance spectroscopy (EIS) analysis, the CA:NH4I:SiO2 has found higher ionic conductivity, lower electrical resistance, and a lesser CPE value than the CA and CA:NH4I. The highest-conducting CA:NH4I:SiO2 and CA:NH4I developed were used in the construction of a single PEMFC, where the obtained power density values were 122.4 and 106.4 mWcm−2. The introduction of SiO2 admixtures with CA:NH4I has found relatively higher power density value than CA:NH4I.

Dye-sensitized solar cell employing chitosan-based biopolymer electrolyte

Conductivity and transport properties of a cost-effective and environment friendly chitosan based solid biopolymer electrolytes which form mechanically robust thick film, have been reported here. A maximum ionic conductivity of ∼ 10-4 S/cm has been achieved by optimizing the concentrations of the salt (LiClO4) and the plasticizer (EC) in the biopolymer electrolyte. Ion transport properties of the biopolymer electrolytes are studied from Raman spectroscopy. A dye-sensitized solar cell (DSSC), with a sandwich structure, is fabricated with chemically synthesized ZnO (∼ 60 nm) as the nanoporous semiconductor material coated with Rose Bengal dye as a photosensitizer, the chitosan biopolymer as electrolyte and platinum as counter electrode. Linear Sweep Voltammetry analysis of the DSSCs illustrates the photovoltaic performance of these cells. Without any external addition of redox couple in the biopolymer electrolytic system, a maximum short-circuit current density of JSC = 0.556 mA/cm2 and open-circuit voltage Voc = 0.605 V with power conversion efficiency 0.051 % is achieved by the DSSC.

Development of Na+ ion conducting solid biopolymer electrolytes based on Na-CMC-SPA hydrogel

Solid polymer electrolytes based on biopolymers are green and environment-friendly materials. Here, solid biopolymer electrolyte (SBPE) hydrogel based on carboxymethyl cellulose is introduced for Na+ ion-based energy storage material. The synthesized SBPE material is biodegradable and shows excellent strength with good flexibility and high elasticity. SBPE-2 has compact packing with inner porous morphology which is helpful in ionic conduction inside the matrix. The ionic conductivity of electrolyte material was recorded in the range of 10-5 S/cm at room temperature and 10-4 S/cm at higher temperatures (>40 °C). The ionic transference number is found to be > 96% in 510 sec. LSV measurements confirm that the SBPEs material can be used in device fabrication up to 2.3 V. These properties of electrolytes make them a promising material for application in energy storage devices.

DFT Study on Na-Ion Conducting Solid Biopolymer Electrolyte-Based on Agar-Agar and NaPF6 for Sodium-Ion Batteries

This research article is focused on the structural, electronic, thermal, and vibrational properties of solid biopolymer electrolytes based on Agar-Agar and sodium hexafluorophosphate (NaPF6) salt. Herein, the density functional theory (DFT) technique is used to investigate these properties. The structural analysis provides information about the interactions between Agar-Agar and NaPF6 and hence interaction energy is analysed. Thermodynamic parameters such as Gibbs’ free energy (G), enthalpy (H), entropy (S), and specific heat (Cv) etc. are studied by frequency analysis at normal temperature pressure (NTP) of titled electrolytes. The chemical descriptors of the electrolytes have been studied using the molecular orbital theory (MOT). Molecular electrostatic potential surface (MEPS) demonstrates the three-dimensional molecular charge distribution and illustrates the electron-rich and deficit regions over the whole electrolyte system. Mulliken population analysis (MPA) gives the identification of intramolecular hydrogen bonding. The theoretical infrared (IR) study confirms the formation of the complex system between Agar-Agar and NaPF6 salt. The overall DFT studies of sodium ion-based biopolymer electrolytes have better possibilities for safe sodium-ion batteries.

Conducting behaviour of a novel solid biopolymer electrolyte for electrochemical application

Conducting behaviour of a novel solid biopolymer electrolyte for electrochemical application

Replacing synthetic polymer electrolytes in energy storage with flexible biodegradable alternatives: sustainable green biopolymer blend electrolyte for supercapacitor device

Flexible free-standing blended solid biopolymer electrolytes (BSBEs) were developed using chitosan (CS) and potato starch (PS) as the host biopolymers for the biopolymer matrix. Potassium thiocyanate (KSCN) was used as the cation provider, while non-toxic glycerol (GCL) was employed as a plasticizer to reduce resistance and enhance the amorphousness of the BSBE films. The structural, morphological, and electrical analyses demonstrated encouraging properties for the BSBE films. The addition of GCL resulted in increased dissociation of KSCN. Deconvoluted Fourier transform infrared (FTIR) spectroscopy was utilized as an accurate method for extracting ion transport parameters. The highest ambient temperature conductivity of 1.40×10−3Scm−1 is recorded at 36 wt% of GCL. The best ion conducting film exhibited a wide potential stability of 2.72 V and an ion transference number (tion) close to unity, with a value of 0.978. The fabricated EDLC demonstrated approximately rectangular cyclic voltammetry (CV) performance and fast-rate charge-discharge behavior with a specific capacitance (Cspc) of 42.11Fg−1. The galvanostatic charge-discharge (GCD) test confirmed the capacitive characteristics of the cell, exhibiting good cyclic stability and excellent outcomes in terms of energy (Ed) and power (Pd) densities over numerous cycles.

Oxide-based synaptic transistors gated by solid biopolymer electrolytes

Oxide-based synaptic transistors gated by solid biopolymer electrolytes

Structural and electrical properties of TSP: CH3COONa amorphous Biopolymer electrolytes for electrochemical cell applications

Solid biopolymer electrolytes have gained enormous attention recently due to their potential as non-toxic, biodegradable properties over their synthetic counterpart. Considering their uses in energy applications, the present investigation aims to synthesize and characterize solid biopolymer electrolytes comprising tamarind seed polysaccharide (TSP) as the host polymer and sodium acetate (CH3COONa) salt as the ionic dopant. The solution cast technique was employed to create free-standing tamarind seed polysaccharide (TSP): Sodium acetate (CH3COONa) solid polymer electrolyte films with varying weight percentages. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) studies investigated the structural and chemical correlation between TSP and CH3COONa. AC impedance spectroscopy was used to test the conductivity and dielectric properties of the prepared polymer films. The conductivity rises with increasing temperature. The maximum conductivity was found to be 1.95 × 10−4 S cm−1 for 80:20 (TSP: CH3COONa) wt.% ratio sample at room temperature (303 K), which was three orders of magnitude higher than the pure TSP (10−7 S cm−1). These polymer electrolyte films showed conductivity that altered with temperature, which follows Arrhenius's behaviour. Dielectric studies showed that dielectric constant and dielectric loss were high at low frequencies and decreased at high frequencies. Wagner's polarisation technique confirmed that charge transport in these polymer electrolyte systems was principally ionic, with the highest tion ( ̴ 0.99) and electrons having a negligible contribution. The discharge studies of the cell showed good stability and performance with OCV at 1.68 V and SCC at 0.69 mA.

Sodium Alginate Doped with Magnesium Perchlorate as Solid Biopolymer Electrolytes for Energy Storage Applications

AbstractThis paper deals with development and characterization of the solid biopolymer electrolyte using Sodium alginate as the host biopolymer and magnesium perchlorate used as a doping salt. Membranes are prepared via solution casting technique. Several characterization techniques, such as X‐ray and diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, AC impedance spectroscopy, linear sweep voltammetry, and transference number measurement are performed to characterize the prepared biopolymer membrane. The highest ionic conductivity 2.41 × 10−3 S cm−1 is observed for prepared solid biopolymer electrolyte contains 40:60 m wt% of NaAlg:Mg(ClO4)2. The electrochemical stability of highest ion conducting biopolymer membrane is observed at 3.62 V. A primary magnesium battery is constructed using the highest ionic conducting biopolymer membrane and the open circuit voltage of the fabricated magnesium battery is found to be 2.0 V.

Environmentally friendly plasticized electrolyte based on chitosan (CS): Potato starch (PS) polymers for EDLC application: Steps toward the greener energy storage devices derived from biopolymers

Biopolymer membranes derived from natural resources are environmentally friendly materials and their use for electrochemical energy storage devices has attracted a great deal of attention. Here, chitosan (CS) and potato starch (PS) doped with ammonium thiocyanate (NH4SCN) were used as host electrolyte. Various weight percent of glycerol (Gly) as a non-toxic plasticizer are used to prepare novel plasticized solid biopolymer electrolytes (PSBEs) through solution casting method, which is subsequently used as a mediator in electric double-layer capacitor (EDLC) application. Inclusion of Gly participated significantly in minimizing the crystallinity nature of the membranes as revealed by the X-ray diffraction (XRD) patterns. Fourier transform infrared (FTIR) spectroscopy revealed the complexation among the constituents of the electrolyte. Ion transport parameters determined by FTIR and electrochemical impedance spectroscopy (EIS) techniques have shown comparable results. The optimum composition of PSBE is achieved when 24 wt% of Gly is added (CPNHG3), which has shown the best ion conductivity (1.62×10−3Scm−1) from the EIS study. This film has exhibited also an excellent ion transference number (tion) of (0.989) and a large electrochemical potential stability (2.1 V) measured by transfer number measurement (TNM) and linear sweep voltammetry (LSV) methods. The restriction to ion movement was observed for the samples overloaded with Gly (32 and 40 wt%) due to the blockage effect, which reflected on ion conductivity and transport parameters. The assembled EDLC device provided a specific capacitance (Cspc) of 16.1 F/g at 10 mV/s scan rate with no sign of redox reaction, which was proven by either cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) techniques. Further, the cyclic stability and high performance of the EDLC regarding energy density, power density, and coulombic efficiency were confirmed throughout the 2500 cycles.

Insight into the Effect of Glycerol on Dielectric Relaxation and Transport Properties of Potassium-Ion-Conducting Solid Biopolymer Electrolytes for Application in Solid-State Electrochemical Double-Layer Capacitor.

The increased interest in the transition from liquid to solid polymer electrolytes (SPEs) has driven enormous research in the area polymer electrolyte technology. Solid biopolymer electrolytes (SBEs) are a special class of SPEs that are obtained from natural polymers. Recently, SBEs have been generating much attention because they are simple, inexpensive, and environmentally friendly. In this work, SBEs based on glycerol-plasticized methylcellulose/pectin/potassium phosphate (MC/PC/K3PO4) are investigated for their potential application in an electrochemical double-layer capacitor (EDLC). The structural, electrical, thermal, dielectric, and energy moduli of the SBEs were analyzed via X-ray diffractometry (XRD), Fourier transforms infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS), transference number measurement (TNM), and linear sweep voltammetry (LSV). The plasticizing effect of glycerol in the MC/PC/K3PO4/glycerol system was confirmed by the change in the intensity of the samples' FTIR absorption bands. The broadening of the XRD peaks demonstrates that the amorphous component of SBEs increases with increasing glycerol concentration, while EIS plots demonstrate an increase in ionic conductivity with increasing plasticizer content owing to the formation of charge-transfer complexes and the expansion of amorphous domains in polymer electrolytes (PEs). The sample containing 50% glycerol has a maximal ionic conductivity of about 7.5 × 10-4 scm-1, a broad potential window of 3.99 V, and a cation transference number of 0.959 at room temperature. Using the cyclic voltammetry (CV) test, the EDLC constructed from the sample with the highest conductivity revealed a capacitive characteristic. At 5 mVs-1, a leaf-shaped profile with a specific capacitance of 57.14 Fg-1 was measured based on the CV data.

Investigations on anomalous behavior of ionic conductivity in NaPF6 salt loaded hydroxyethyl cellulose biodegradable polymer electrolyte for energy storage applications

AbstractThis article investigates the influence of NaPF6 salt content (0–30 wt.% in a varying interval of 5 wt.%) on the structural, electrical, and biodegradable properties of HEC/NaPF6 solid biopolymer electrolyte (SBE) films. The interaction of salt with the HEC polymer matrix is confirmed by FTIR and SEM studies. The elemental composition and mapping confirm the appearance of NaPF6 moieties in the HEC polymer matrix. XRD deconvolution reveals that HEC samples with 20 wt.% (H4) and 10 wt.% of salt (H2) have a significantly lower crystallinity index than pure HEC polymer. The H2 and H4 samples show the highest room temperature conductivity values (1.62 × 10−5 and 1.13 × 10−5 S cm−1, respectively) among all other prepared samples since carrier concentration influences the ionic conductivity and shares a similar order of conductivity. Thus, the H2 and H4 samples are employed as electrolyte separators in the sodium ion battery, and the results suggest that the H2‐based electrolyte system is more significant. Battery matrices like open circuit voltage (V), current density (μA cm−2), power density (mW kg−1), energy density (Wh kg−1) and discharge capacity (μA h−1) were calculated and found to be 2.48, 5.49, 44.60, 1.69, and 71.05, respectively for H2 electrolyte based cell. Wagner polarization reveals that H2 and H4 constitute the predominant charge carriers (ions) with total ion transference numbers of ⁓0.98 and ⁓0.99, respectively. To evaluate sample degradability, H2 and H4 samples were subjected to 20 and 5‐day biodegradation processes, during which the polymers completely (100%) broke down.

Study on the electrical properties of gum tragacanth - LiClO4 natural polymer electrolyte

Solid biopolymer electrolytes in the form of gum tragacanth and lithium perchlorate doped with different weight ratios of propylene carbonate (10, 20, 30, and 40 wt%) were fabricated by solution casting method. The prepared electrolytes were studied for their electrical properties using Electrochemical Impedance Spectroscopy. An ionic conductivity value of 1.06 × 10−3 Scm−1 was attained at 303 K. The temperature dependence of the electrolytes showed Arrhenius behaviour and the activation energy was calculated to be low for the maximum conducting electrolyte. Wagner's dc polarisation method's estimation of the ionic transference number shows that Li+ ions are the predominant conducting species.