Solid Polymer Electrolyte System Research Articles

Single-Ion Conductor Polymer Electrolytes for All Solid-State Batteries

Poly(ethylene oxide) (PEO) can be considered the most widely studied and applied, all solid-state (solvent free) polymeric lithium ion conductor.1 However, the material suffers from numerous drawbacks: most importantly, PEO shows a considerable tendency towards crystallization.2 Consequently, linear PEO shows a drastic increase in ionic conductivity above its melting temperature, typically ranging between 40 and 60 °C depending on the molecular weight. This temperature-dependence strongly impedes the commercial application of PEO as substitute for the state-of-the-art liquid, flammable carbonate electrolytes of today’s lithium ion batteries. One major benefit of solid (polymer) electrolytes lies in their high mechanical stiffness along with shape-flexibility and elasticity, which could be used to avoid spacer membranes. This could not only increase the specific capacity of the cell by weight reduction and decreased electrode distance but also impede lithium dendrite growth at the electrode interfaces.Many reports find that LiTFSI in combination with PEO delivers among the highest ionic conductivities for solid polymer electrolytes. The combination of the small Li+ cation and the bulky, highly charge-delocalized TFSI- anion leads to a very weakly associated salt structure. The TFSI- anion contributes up to 80 % to the ionic conductivity in typical PEO/LiTFSI mixtures by propagating through the electrolyte.3 However, TFSI- cannot be converted nor intercalated electrochemically at the electrodes in a battery application. During discharge, anions accumulate at the anode in opposite direction to the internal electric field, depolarizing the cell and thereby diminishing its specific capacity and power. Furthermore, the high concentration of anions at either electrode can facilitate the growth of unwanted lithium dendrites at the surface. The concept of a single-ion conducting electrolyte tackles these issues by spatially fixating the anions onto a scaffold, e.g. a polymer backbone. This restricts the anion movement and helps to increase the percentage of current transported only by lithium cations, which is referred to as the lithium transport number tLi+ .A synthetic approach to combine the lithium ion coordinating chemistry of a PEO-based polymer with a sterically frustrated chain architecture can be found in brush-like graft copolymers.4 We recently presented a convenient two-step pathway for the synthesis of clickable PEO-based electrolyte materials.5 In the first step, epoxy- as well as alkyne-functionalized glycidyl propargyl ether (GPE) is directly converted to P(GPE) by monomer-activated, anionic ring-opening polymerization (AROP, fig. a). We showed the consequent functionalization of this versatile polymer backbone in the second step by copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC, Click-chemistry) under very mild conditions and with complete removal of copper catalyst traces. We could tailor the polymer composition by the sequential addition of the corresponding, azide-equipped side-groups; in our case tri(ethylene glycol) azide (EG3-N3) and benzyl azide (Bn-N3) and a specially synthesized, clickable lithium bis(trifluoromethanesulfonyl)imide azide (LiTFSI-N3) which integrates the concept of single-ion conduction (fig. a,b)As an improved version of the previously presented, sequentially clicked graft copolymers, we prepared single-ion conducting P[GPE-(EG3x-ran-LiTFSIy)]100 electrolytes (fig. c) by clicking EG3-N3 as well as LiTFSI-N3 sidegroups onto the P(GPE) backbone with different amounts of lithium salt in the structure.6 We analyzed these materials in terms of composition (NMR, SEC), temperature behavior (TGA, DSC) as well as applicability as lithium ion conducting electrolytes (ionic conductivity, lithium transport number, cyclovoltammetry, battery cycling and extended DRT analysis). Additionally, we synthesized the fully EG3-grafted P(GPE-EG3)100(fig. d) as a matrix polymer and mixed it with LiTFSI to obtain a salt-in-polymer electrolyte as comparison dual-ion system. Both the type of lithium salt as well as the ion-conducting matrix are the same in both electrolytes, but a significantly increased lithium transport number is expected for the single-ion conductor. Herein we present two solid polymer electrolyte systems based on the versatile P(GPE) backbone – one of them single-ion conducting – and compare them in a detailed and fundamental study.References(1) Armand, M. Solid State Ionics 1983, 9-10, 745–754. DOI: 10.1016/0167-2738(83)90083-8.(2) Berthier, C.; Gorecki, W.; Minier, M.; Armand, M. B.; Chabagno, J. M.; Rigaud, P. Solid State Ionics 1983, 11 (1), 91–95. DOI: 10.1016/0167-2738(83)90068-1.(3) Bouchet, R.; Maria, S.; Meziane, R.; Aboulaich, A.; Lienafa, L.; Bonnet, J.-P.; Phan, T. N. T.; Bertin, D.; Gigmes, D.; Devaux, D.; Denoyel, R.; Armand, M. Nature materials 2013, 12 (5), 452–457. DOI: 10.1038/NMAT3602.(4) Nishimoto, A.; Watanabe, M.; Ikeda, Y.; Kohjiya, S. Electrochimica Acta 1998, 43 (10-11), 1177–1184. DOI: 10.1016/S0013-4686(97)10017-2.(5) Krimalowski, A.; Thelakkat, M. Macromolecules 2019, 52 (11), 4042–4051. DOI: 10.1021/acs.macromol.9b00206.(6) Hahn, M.; Rosenbach, D.; Krimalowski, A.; Nazarenus, T.; Moos, R.; Thelakkat, M.; Danzer, M. A. Electrochimica Acta 2020, 136060. DOI: 10.1016/j.electacta.2020.136060. Figure 1

Enhancement of proton conduction in carboxymethyl cellulose-polyvinyl alcohol employing polyethylene glycol as a plasticizer

The present study deals with the enhancement of proton transport and conduction properties of solid polymer electrolyte (SPE)-based carboxymethyl cellulose (CMC) blended with polyvinyl alcohol (PVA) doped with ammonium nitrate (NH4NO3) and plasticized with various compositions of polyethylene glycol (PEG). The SPE system was successfully prepared using an economical method, the solution casting technique, and analysed by Fourier transform infrared spectroscopy and electrical impedance spectroscopy. The infrared spectra show that interaction had occurred at O–H and COO− from CMC when PEG was added which prevailed the enhancement of ion dissociation. Glass transition measurement highlighted that the interaction between CMC–PVA–NH4NO3 and ethylene carbonate at 8 wt% give the most plasticization effect that achieved the lowest Tg. The highest conductivity of the SPE system achieved at ambient temperature was 1.70 × 10−3 S cm−1 for a non-plasticized sample, and further enhanced to 3.00 × 10−3 S cm−1 when 8 wt% PEG was incorporated into the SPE system. The sample with the highest conductivity was found to obey the Arrhenius behaviour with a function of temperature. The ionic conductivity of the SPE system was shown to be primarily influenced by a number of ions (η), ion mobility (μ) and diffusion coefficient (D).

Enhancement of energy storage capacity in lithium polymer batteries incorporated with zirconium oxide nano powders

In this work, three poly-methyl methacrylate (PMMA) hosted solid polymer electrolyte systems were prepared by a solution cast technique. A fixed amount of PMMA and nano Zirconium dioxide (ZrO2) were implemented as ceramic filler and lithium hexafluorophosphate (LiPF6) as dopant salt. The study was carried out using Electrochemical Impedance Spectroscopy (EIS) and Scanning Electron Microscope (SEM). The integrating 20 wt% of Propylene carbonate (PC) into PMMA enhanced the ionic conductivity with another addition of 5 wt% of LiPF6, the ionic conductivity is increased to from 1.94 × 10–11 Scm−1 to 2.97 × 10–09 Scm−1. This has inferred the enhancement of charge carrier density in the polymer electrolyte. A further addition of ceramic fillers with 10 wt% of ZrO2, boosted the ionic conductivity to 9.45 × 10–11 Scm−1 and 4.44 × 10–9 Scm−1, respectively. The SEM images showed the formation of three-dimensional networks with dispersion of ceramic fillers. It can be concluded that appropriate amount of lithium salt (5 wt% of LiPF6) and ceramic filler (10 wt% of ZrO2) enhances the ionic conductivity of the PMMA-based solid polymer electrolyte. The electrical conductivity of PMMA-LiPF6 polymer blend with different concentrations of ZrO2 as a nano filler has been studied. The polymer blend electrolyte was prepared in the form of thin films using solution casting technique. The blend was characterized by Scanning Electron Microscopy (SEM).

Anisotropic ion transport in 2D polymer single crystal-based solid polymer electrolytes

Solid polymer electrolytes (SPEs) are promising for the next-generation all-solid-state lithium metal battery (LMB) applications. The effect of semicrystalline structure on ion transport is two-fold: the crystalline domains provide a tortuous diffusion pathway (structural effect) while the tethered chains can cause sluggish ion diffusion (dynamic effect). These two effects are intertwining in a bulk semicrystalline SPE system. In this work, we fabricate a series of polymer single crystal (PSC)-based SPEs by infiltrating lithium bis(trifluoromethylsulfonyl) imide (LiTFSI) into poly(ethylene oxide) (PEO) PSC films. The obtained SPE films show anisotropic conducting behavior with the in-plane conductivity being one to three orders of magnitudes greater than the through-plane conductivity, which can be attributed to the PSC-guided ion transport. The room temperature in-plane conductivity of the PSC SPE can be comparable to its amorphous counterpart, indicating that the tortuosity effect plays a major role in the reduced ionic conductivity of semicrystalline SPEs. PSC-LiTFSI superstructure is observed in the PSC SPEs due to selective perforation of the crystalline PEO lamellae by LiTFSI salts. This work demonstrates the importance of the crystalline morphology on the ion transport in semicrystalline SPEs.

Study of the conductivity of solid polymeric electrolyte based on PVA/GA blend with addition of acetic acid

This study searches the ion transport behavior and structural investigation of solid polymer electrolytes (SPEs) containing poly(vinyl alcohol) (PVA) and gum arabic (GA) with diverse amount of acetic acid for a possible application in electrochemical devices. The SPE system was prepared by the casting method and studied by electrical impedance spectroscopy (EIS), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The best ionic conductivities of 2.22 × 10−5 and 17.70 × 10−5 S.cm−1 at 25 and 80 °C, respectively, were measured for PVA/GA with 42 wt% of acetic acid. FTIR analysis confirmed PVA, GA, and acetic acid –OH, –C=O, and –COO− characteristic peaks. The ionic conductivity of PVA/GA SPE was affected by its ionic transport properties and amorphousness, which was revealed by deconvolution of XRD diffractograms. Additionally, AFM images proved predominantly homogeneous surface of the samples.

Study on electrochemical properties of CMC-PVA doped NH4Br based solid polymer electrolytes system as application for EDLC

In the present work, solid polymer electrolytes (SPEs) based CMC-PVA blend doped with various contents of NH4Br were successfully prepared via solution-casting technique. The prepared samples were then characterized with respect to its thermal and conduction properties by using differential scanning calorimetry (DSC) and impedance spectroscopy. The highest dc conductivity at room temperature is observed to be 3.21 × 10−4 S cm−1 for a sample that consists of 20 wt.% NH4Br which demonstrated good thermal stability of Tg. The CMC-PVA doped NH4Br recorded an increment on the ionic conductivity with the increase in temperature, and thus obeys the Arrhenius behavior. The potential window for the highest conducting sample was found to be plateaued at 1.55 V. The performance of the EDLC fabricated with highest ionic conducting CMC-PVA doped NH4Br was also examined through cyclic voltammetry (CV) and it was shown that the specific capacitance increased as the scan rate reduced. Based on the charge-discharge profile, it is apparent that the proposed system has excellent cyclic retention as it is able to keep the performance of the EDLC at ~88% even after 1000 cycles.

Electrochemical Impedance study of Proton Conducting Polymer Electrolytes based on PVC Doped with Thiocyanate and Plasticized with Glycerol

Solid polymer electrolyte (SPE) system based on poly (vinyl chloride) PVC doped with ammonium thiocyanate (NH4SCN) salt has been prepared by solution cast techniques using glycerol as a plasticizer and THF tetra-hydro furan as a solvent. To examine the electrical properties of the electrolyte films the electrochemical impedance spectroscopy (EIS) has been used. The effect of glycerol on electrical properties and structure of the plasticized PVC-based polymer electrolyte was examined, and the various weight ratio of glycerol plasticizer (%5, %10, %15, and % 20) of PVCNH4SCN weight is well correlated. Electrolytes are the heart of electrochemical devices and their conductivity investigation is crucial from the viewpoint of electrochemical device application. EIS electrode impedance spectroscopy was used to determine the bulk resistance Rb of the films at room temperature. The increase of the ionic conductivity with an increase in the amount of glycerol was observed through an impedance study, and the maximum ionic conductivity was 1.02512 x 10-6 S cm-1 obtained from (PVC-%20 NH4SCN-%20 glycerol) system. Dielectric relaxation studies of the polymer electrolyte film have been studied. The rise of the dielectric polarization of the films is proved by increases in a dielectric constant and dielectric loss. The peaks appeared in the imaginary part of the electric modulus reveals that ion conduction occurs through the viscoelastic relaxation dynamic. In the AC conductivity pattern plateau region ascribed to DC conductivity is appeared.

A Study on Processing Parameters Affecting Solid Polymer Electrolytes Performances

In the modern world, the rapid advancement of new technologies is accompanied by an increasing energetic demand. Following today`s trend, energy consumption will undoubtedly increase in the following years. Over the last 50 years, lithium-metal batteries have been considered as potential candidates for long-term high-performance electrochemical storage. (1) Although their operation is effective, they still present limitations mainly due to lithium dendrite growth associated with electrodeposited Li+ from the electrolyte on the anode material. This phenomenon causes internal short-circuits resulting in premature battery failure. (2) Various solid-state battery systems are being developed in hope to resolve the said issue. Amongst others, solid polymer electrolytes (SPE) have been investigated since Armand`s work in the 80`. (3) Even though these systems have non-flammable properties and successfully suppress dendrite growth, most SPEs do not reach ionic conductivities values higher than 10-3 S/cm at room temperature and offer lower energy densities and cycle number compared to the standard liquid electrolyte counterpart. (4) As a result of that, an increasing number of published literature shows off new engaging SPE systems. However, oftentimes, the presented performances are hardly reproducible due to the lack of precise and detailed experimental conditions. It is believed that some overlooked factors during processing may affect the aforementioned performances. (5-7) Certain parameters that affect ionic conductivities of SPEs have been investigated by techniques including but not limited to electrochemical impedance spectroscopy (EIS) and solid-state 7Li-NMR. It will be demonstrated that these parameters must be precisely controlled to ensure the reproducibility and the validity of measurements. Finally, it will be shown that this study can be applied to several types of polymers.1: Hall P. J., Bain E. J., Energy Policy, 36, 4352 (2008).2: Lisbona D., Snee T., Process. Saf. Environ., 89, 434 (2011). 3: Armand M. B., Ann. Rev. Mater. Sci. 16, 245 (1986).4: Penghui Y., Haobin Y., Zhiyu D., Yanchen L., Juan L., Marino L., Junwei W., Xingjun L., Front. Chem., 7, 522 (2019).5: Fullerton-Shirey S. K., Maranas J.K, Macromolecules, 42, 2142 (2009).6: Devaux D., Bouchet R., Glé D., Denoyel R., Solid State Ion., 227, 119 (2012).7: Wang X., Zhang L., Li G., Zhang G., Shao Z.G., Yi B., Electrochim. Acta, 158, 253 (2015)

Influence of tetraglyme towards magnesium salt dissociation in solid polymer electrolyte for electric double layer capacitor

Most of commercialized electrical double layer capacitors (EDLCs) with liquid electrolyte are bulky, non-flexible and unsafe which require solid polymer electrolyte (SPE) as the replacement. Herein, SPE containing tetraglyme as the ionic conductivity booster was prepared in which polyvinyl alcohol (PVA), magnesium trifluoromethane sulfonate (Mg (Tf)2) and tetraglyme (TEDGME) have been utilized as the host polymer, salt and additive, respectively. After the addition of TEDGME, the SPE exhibited a significant boost in ionic conductivity from 1.43 × 10−9 to 3.10 × 10−5 S cm−1. This is attributed to the presence of multiple ether oxygen atom functional group from TEDGME that provides more charge carriers. Fourier transform infrared spectroscopy authenticates the formation of complex within the SPE systems which indicates the formation of good interaction between the host polymer and the salts. X-ray diffraction analysis demonstrates the reduction in crystallinity of the SPE after the addition of TEDGME which is beneficial for the ion diffusion. The maximum specific capacitance achieved by the EDLC employing the SPE incorporated with TEDGME is 6.34 F/g at 0.04 A/g, with the rate capability of 74.1%.

Enhancement of Ionic Conductivity and Dielectric Permittivity for PMMA-Based Polymer Electrolyte with BaTiO3NanoFiller

The design of the lithium polymer battery with excellent performance needs proper exploration of the materials. Poly(methyl methacrylate) (PMMA)-hosted solid nanocomposite polymer electrolyte systems are prepared by solvent-casting technique. A fixed amount of propylene carbonate (PC) is used as a plasticizer, barium titanate (BaTiO[Formula: see text] as a nanofiller and lithium hexafluorophosphate (LiPF[Formula: see text] as a dopant salt. The characterization of nanocomposite solid polymer electrolyte (SPE) was carried out using scanning electron microscope (SEM), and the outcome revealed the formation of a three-dimensional network with dispersed nanofillers. The dielectric constants and ionic conductivities for different wt.% of nanofiller with different temperature ranges are measured by impedance analyzer. It is observed that for 15[Formula: see text]wt.% of nanofiller-mixed electrolyte sample, a highest dielectric constant of 5166 and a maximum ionic conductivity of [Formula: see text] S[Formula: see text][Formula: see text][Formula: see text]cm[Formula: see text] are achieved.

A Boron‐Doped Diamond Anode for the Electrochemical Removal of Parabens in Low‐Conductive Solution: From a Conventional Flow Cell to a Solid Polymer Electrolyte System

AbstractSolution conductivity plays a fundamental role for the employment of electrochemical advanced oxidation processes (EAOPs) and in the determination of their energy consumption. In this paper, a conventional flow cell based on a boron‐doped diamond (BDD) anode that requires the addition of supporting electrolyte, is compared with a cell setup based on solid polymer electrolyte (SPE). The new cell configuration avoids the addition of salt to increase solution conductivity. The performances of the two systems are compared for the treatment of different solutions containing methylparaben, ethylparaben and propylparaben. Both systems are able to remove all the three parabens, but the SPE‐system provided a better performance, with a maximum COD removal of 91 % and energy consumption of 16.25 kWh m−3, whereas the conventional system can remove a maximum of 81 % consuming 10.92 kWh m−3. The influences of parameters such as current density, flow conditions and supporting electrolyte concentration were analyzed, and results confirm that the SPE system is a promising system to treat low‐conductive solutions polluted by parabens.

Low-volume Electrolytic Enrichment for Tritium Measurement Using Improved Solid Polymer Electrolyte System at NIFS and Its Application

Low-volume Electrolytic Enrichment for Tritium Measurement Using Improved Solid Polymer Electrolyte System at NIFS and Its Application

Studies on ionics conduction properties of modification CMC-PVA based polymer blend electrolytes via impedance approach

In this study, the modification of cellulose derivative namely carboxymethyl cellulose (CMC) blended with polyvinyl alcohol (PVA) and doped with different content of NH4Br based solid polymer electrolytes (SPEs) prepared via solution casting method is investigated. The FTIR analysis demonstrated the interaction between CMC-PVA and NH4Br via COO−. The optimum ionic conductivity at ambient temperature is found to be 3.21 × 10−4 S/cm for the sample containing 20 wt% NH4Br with the lowest percentage of crystallinity and total weight loss. The conductivity-temperature relationship for the entire SPEs system obeys Arrhenius behaviour. Besides that, based on the Nyquist fitting analysis, it is shown that the ionic conductivity of the SPEs is primarily influenced by the ionic mobility as well as the ions diffusion coefficient. The H+ transference number obtained using non-blocking reversible electrode is 0.31, which further indicates that the conduction species is predominantly due to the cationic conduction.

Sterically-encumbered ionenes as hydroxide ion-conducting polymer membranes

Abstract Hydrogen/oxygen-based electrochemical energy conversion cells that operate under highly alkaline conditions deploy inexpensive electrocatalysts compared to their acidic counterparts. Solid polymer electrolyte (SPE) cells offer a reduced system footprint, and an additional reduction in capital cost. Alkaline membrane, SPE systems are attractive because they offer a synergistic combination of the two cost savings. Durable, hydroxide-conducting SPEs operating in highly caustic media are lacking because organic molecules and polymers, particularly their cationic derivatives, are inherently unstable to caustic conditions. This review focuses on an emerging class of alkaline SPE's, Ionenes: polymers that incorporate cations directly into the polymer backbone. The purpose of this opinion piece is to highlight the fact that fixed cationic charges may be incorporated into the polymeric backbone to provide membranes with high conductivity, mechanical strength, and stability, and to dispel the widely-held view that distancing a cationic group from the polymer backbone is a necessary requirement.

Strong and Flexible Composite Solid Polymer Electrolyte Membranes for Li-Ion Batteries.

A composite solid polymer electrolyte (CSPE) is studied in this work to alleviate the concerns associated with poor mechanical strength of a solid polymer electrolyte (SPE) system composed of poly(ethyleneglycol)diacrylate, an electrolyte lithium bis(trifluoromethane)sulfonamide, and a plasticizer succinonitrile. CSPE is fabricated by incorporating the ingredients of SPE in the macroporous membranes of syndiotactic polystyrene to render flexibility and mechanical robustness with a 6-fold increase in tensile strength over SPE. The data from differential scanning calorimetry and wide-angle X-ray diffraction confirm the amorphous nature of the polymeric domains of SPE that produce high room-temperature ionic conductivity of ∼0.43 mS/cm. The flexible CSPE membranes are used as the electrolyte in Li-ion battery (LIB) half cells in conjunction with lithium iron phosphate as the counter electrode. The use of CSPE helps expand the electrochemical window of the cell to 5 V, indicating strong potential in the fabrication of flexible rechargeable LIBs.

Plasticized solid polymer electrolyte based on natural polymer blend incorporated with lithium perchlorate for electrical double-layer capacitor fabrication

A plasticized solid polymer electrolyte system is prepared using polymer blend of methyl cellulose–potato starch with lithium perchlorate (LiClO4) as dopant salt and glycerol as plasticizer. Transport properties of the electrolytes are investigated using electrical impedance spectroscopy (EIS). By applying a method proposed by Arof et al. which was found to be suitable for both Arrhenius and Vogel–Tammann–Fulcher (VTF) type of electrolytes, the number density (n), diffusion coefficient (D), and mobility (μ) of ions are found to be influenced by the concentration of glycerol. From ion and electron transference number analysis, it is verified that ions are the main charge carriers. Linear sweep voltammetry (LSV) verifies the suitability of the most conductive electrolyte to be employed in the carbon-based symmetric electrical double-layer capacitor (EDLC) fabrication. The EDLC has been tested using the galvanostatic charge–discharge and cyclic voltammetry (CV) techniques. The specific capacitance (Csp) of the electrode using CV at a sweep rate of 2 mV s−1 is found to be 61.58 F g−1. The EDLC has been tested for 1000 charge–discharge cycles with the highest Csp value of 28.04 F g−1.

One-pot synthesis of crosslinked polymer electrolyte beyond 5V oxidation potential for all-solid-state lithium battery

A new crosslinked copolymer electrolyte is prepared with a simply method. The optimal electrolyte presents a maximum conductivity of 1.15 × 10−4 S cm−1 at 60 °C. Especially, this new electrolyte presents an outstanding electrochemical stability not only for a wide electrochemical window (0–5.1 V) but also for a long–term compatibility with the Li metal. Due to electrochemical stability, LiMn0.2Fe0.8PO4 is selected as cathode material cycling between 3 V and 4.25 V. Moreover, a convenient integration method is used in this work to enhance the interfacial contact between cathode and electrolyte. Finally, the all-solid-state battery LiMn0.2Fe0.8PO4/Li shows a maximum capacity of 161.1 mAh g−1 and an excellent capacity retention ratio of 94.5% after 100 cycles. This new crosslinked polymer electrolyte may provide useful insights for introducing high voltage cathode material rather than LiFePO4 only into solid polymer electrolytes system.

Characterization of biodegradable solid polymer electrolyte system based on agar-NH4Br and its comparison with NH4I

Concerning the pollution-free and eco-friendly materials, the prospect of using biopolymer as ion conducting matrix has been investigated in this study. Biopolymer electrolyte based on agar with different concentrations of NH4Br has been prepared by solution casting technique using water as solvent. The prepared electrolytes are characterized by X-ray diffraction analysis, Fourier-transform infrared spectroscopy, AC impedance spectroscopy, and electrochemical stability. X-ray diffraction is done to study the nature (amorphous/crystalline) of the polymer membranes. The complexation of the prepared polymer electrolytes has been studied using Fourier-transform infrared (FTIR) spectroscopy. The maximum ionic conductivity of 1.33 × 10−4 S cm−1 has been obtained for 50 M.wt% NH4Br with agar polymer electrolyte. The temperature dependence of ionic conductivity of the prepared polymer electrolytes obeys Arrhenius law. The ionic transference numbers of mobile ions have been estimated by Wagner’s dc polarization method and the results reveal that the conducting species are predominantly ions. The electrochemical stability is studied by linear sweep voltammetry. A battery has been constructed using the highest conductivity sample and its output voltage is found to be 1.80 V. A proton-exchange membrane fuel cell fabricated with the 50 M.wt% NH4Br-doped agar polymer electrolyte exhibited an output voltage of 500 mV. These results of 50 M.wt% NH4Br-doped agar have been compared with 50 M.wt% agar:50 M.wt% NH4I biopolymer electrolyte.

Investigation on transport and thermal studies of solid polymer electrolyte based on carboxymethyl cellulose doped ammonium thiocyanate for potential application in electrochemical devices

In this work, a free standing and flexible solid polymer electrolyte (SPE) based on non-hazardous and environmental friendly material, carboxymethyl cellulose (CMC) was successfully produced in order to overcome environmental and pollution issues. The effect of doping ammonium thiocyanate (NH4SCN) into SPE based on carboxymethyl cellulose (CMC) on transport, thermal and electrochemical stability window properties have been investigated for potential application in electrochemical devices. CMC-NH4SCN SPE was prepared via solution casting technique. The properties of the prepared CMC-NH4SCN SPE were characterized via Fourier transform infrared spectroscopy (FTIR) deconvolution, transference number measurement (TNM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and linear sweep voltammetry (LSV) techniques. FTIR deconvolution was performed in order to investigate the dissociation of ions and transport properties of CMC-NH4SCN SPE system and it can be correlated with the ionic conductivity of CMC-NH4SCN SPE system. The result of TNM was obtained via a DC polarization method where the ionic transference number for the highest conducting CMC-NH4SCN SPE was found to be 0.93. Thus, it can be suggested that the conducting species for the highest conducting CMC-NH4SCN SPE are mainly due to ions. TGA was performed to investigate the thermal stability of CMC-NH4SCN SPE. The value of glass transition temperature of CMC-NH4SCN SPE was obtained from DSC analysis. Electrochemical stability window of the highest conducting CMC-NH4SCN SPE obtained from LSV technique was up to 1.6 V. As a result, it can be inferred that the highest conducting CMC-NH4SCN SPE had shown a promising performance and has a great potential to be applied in electrochemical devices application such as proton batteries.

Preparation and characterization studies of PMMA–PEO-blend solid polymer electrolytes with SiO2 filler and plasticizer for lithium ion battery

Solid polymer electrolyte systems comprising of polyethylene oxide (PEO) and polymethyl methacrylate (PMMA) as blended polymer host, lithium trifluoromethanesulfonate (LiCF3SO3) as dopant salt, ethylene carbonate (EC) as plasticizer, and silicon dioxide (SiO2) as inorganic filler were prepared by solution casting method. PMMA–PEO–EC–LiCF3SO3–SiO2-blend solid polymer electrolytes were prepared to study the blending effect of PMMA into PEO solid polymer electrolytes. All the resulted solid polymer electrolytes were characterized using electrochemical impedance spectroscopy (EIS), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) methods. In the present study, the XRD, FTIR, SEM, and DSC results show clear evidence of the miscibility of PMMA and PEO. The incorporation of PMMA into the PMMA–PEO-blend solid polymer electrolytes shows significant improvement on ionic conductivity when small amount of PMMA is used. The highest ionic conductivity of 2.6301 × 10−4 S/cm is achieved for 5 wt% PMMA and 95 wt% PEO-blend solid polymer electrolytes at room temperature. The ionic conductivity values are found to be decreased when a higher wt% of PMMA is added. Upon incorporation of 20 wt% of PMMA, the ionic conductivity values are found in range of 10−6 to 10−7 S/cm. This finding is comparable with the reported results for gel-type polymer electrolytes. Hence, the amount of PMMA used in the PMMA–PEO-blend systems is crucial in the preparation of PMMA–PEO-blend solid polymer electrolyte.