Properties Of Solid Polymer Electrolytes Research Articles

A novel approach to enhance the ionic conductivity of silver nanoparticles incorporated PVA:NaBr polymer electrolyte films via fast neutron irradiation

This study investigates the unprecedented impact of fast neutron irradiation on the structural, electrical, and morphological properties of solid polymer electrolytes (SPEs). The SPE, a poly (vinylalcohol) (PVA)-sodium bromide (NaBr) based matrix with the incorporation of silver nanoparticles (AgNPs), was prepared via a solution casting method and subjected to various time intervals of fast neutron irradiation. X-ray diffraction (XRD) analysis revealed a distinct trend in the polymer electrolyte sample's amorphous phase, with decreased levels at lower neutron fluence and augmented levels at higher fluences. Fourier transform infrared (FTIR) spectroscopy highlighted plausible interactions leading to chain scission and cross-linking. Optical investgations below 300 nm exhibited increased absorbance and a shifted position of the surface plasmon resonance peak correlated with AgNPs. Validation of structural changes in the Ag-incorporated PVA-NaBr system was supported by reduced bandgap and elevation in Urbach energy, corroborating FTIR findings. Enhanced thermal stability was confirmed using thermogravimetric (TGA) analysis. Morphological modification upon irradiation were evident via Field emission scanning electron microscope (FESEM). Transport properties evaluated by Nyquist plot fitting showcased escalating room temperature conductivity with neutron fluence, and the highest conductivity obtained was 4.38 × 10−3 S/cm, an order higher than the pristine sample. Transference number measurements (TNM) indicated that the primary charge carriers are ions rather than electrons. This novel approach confirms that neutron irradiation can be used as a potential way to obtain highly conductive polymer electrolyte films.

Anion-Immobilized Gel Polymer Electrolyte with a High Ion Transference Number for High-Performance Lithium/Sodium Metal Batteries.

Due to their high energy density, lithium/sodium metal batteries (LMBs/SMBs) are expected to be the next generation of energy storage systems. However, the further application of alkali metal batteries based on liquid electrolytes is limited due to increasing safety concerns. Gel polymer electrolytes (GPEs), which combine the advantages of the high ionic conductivity of liquid electrolytes and excellent mechanical properties of solid polymer electrolytes, are considered to play an irreplaceable role in the realization of high-performance alkali metal batteries. In this work, a flexible boron-containing GPE (B-GPE) with a cross-linked polymer network structure is prepared by a UV-induced process. The as-prepared B-GPE exhibits good ionic conductivity and has an extremely high ion transference number due to the electron-withdrawing effect of the boron moiety and the facile electrolyte uptake ability of the ethylene oxide chain. Furthermore, a "gentle" electrode/electrolyte contact is designed by a one-step in situ polymerization method, which can enhance ion transport within the electrode and at the electrode/electrolyte interface due to the presence of a continuous polymer phase for ion conduction. Therefore, LMBs and SMBs containing B-GPE are able to effectively inhibit the growth of dendrites while exhibiting excellent cycling stability. These comprehensive results indicate that this novel B-GPE possesses potential applications for high-performance alkali metal 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.

Largely Promoted Mechano‐Electrochemical Coupling Properties of Solid Polymer Electrolytes by Introducing Hydrogen Bonds‐Rich Network

AbstractSolid polymer electrolytes (SPEs) and their composites are the most promising spices to access the commercial application in all‐solid‐state lithium batteries, where definite requirements for SPEs should be satisfied including moderate mechanical strength, high Li‐ion conductivity, and stable electrode/electrolyte interface. Herein, polyurethane‐based polymer (PNPU) is designed to further construct the hybrid solid polymer electrolyte (named as PNPU‐PVDF‐HFP) with poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) for high energy density solid‐state lithium metal batteries. The theoretical calculation and characterization demonstrate that PNPU‐PVDF‐HFP SPEs still maintain the multiple hydrogen bonding modes of PNPU, which contributes a significantly improved mechanical properties of the polymer membrane with compact structure. Moreover, it is corroborated that PNPU is involved to form the double Li+ transport paths in the hybrid electrolyte, accelerating the migration of lithium ions. Therefore, PNPU‐PVDF‐HFP SPEs are achieved with suitable tensile strength of 5.16 MPa and high elongation of 140.8%, high ambient ionic conductivity of 4.13 × 10−4 S cm−1, excellent ductile, and stability on the interface of lithium metal anode. The Li/ LiFePO4 and Li/Li[Ni0.8Co0.1Mn0.1]O2 solid‐state batteries using PNPU‐PVDF‐HFP SPEs present a stable cycling performance at 30 °C. This study provides a feasible strategy to achieve mechano‐electrochemical coupling stable SPEs for solid‐state batteries.

Enhanced properties of solid polymer electrolytes by a bilayer nonwoven PET/nanofiber PVDF substrate for use in all-solid-state lithium metal batteries

Enhanced properties of solid polymer electrolytes by a bilayer nonwoven PET/nanofiber PVDF substrate for use in all-solid-state lithium metal batteries

Enhanced safety of polymer solid electrolytes by using black phosphorene as a flame-retardant

Solid polymer electrolytes attract much attention due to their good flexibility and good interfacial contact property. However, the inherent thermal instability of polymers inhibits the practical application of solid polymer electrolytes. In this work, the black phosphorene nanosheet, a fire-retardant additive, was introduced and incorporated into poly (ethylene oxide) (PEO)-based solid polymer electrolyte to improve the thermal property. The BP/PEO based solid polymer electrolyte membrane is thermally stable, nonflammable, and mechanically strong, more than 400 h of cycling with low polarization based on a Li-Li symmetric cell was achieved. LiFePO4//Li solid state battery with the BP/PEO based solid polymer electrolyte shows a high-capacity performance (153 mAh g−1 at 0.1 C) as well as cycling performance (100 cycles at 0.2 C rate) at 60 °C. The flammability tests indicated that a small amount of black phosphorene can make the electrolyte display good non-flammability. In the micro-scale combustion calorimetry test, the peak heat release rate of BP/PEO based solid polymer electrolyte reduced by 62.5% and flame ignition time is slower compared with the PEO based solid polymer electrolyte without incorporating black phosphorene. The present work demonstrated that the black phosphorene nanosheets do not weaken the electrochemical properties of solid polymer electrolytes, but also enhance their thermal properties.

Decoupling Ion Transport and Matrix Dynamics to Make High Performance Solid Polymer Electrolytes.

Transport of ions through solid polymeric electrolytes (SPEs) involves a complicated interplay of ion solvation, ion-ion interactions, ion-polymer interactions, and free volume. Nonetheless, prevailing viewpoints on the subject promote a significantly simplified picture, likening ion transport in a polymer to that in an unstructured fluid at low solute concentrations. Although this idealized liquid transport model has been successful in guiding the design of homogeneous electrolytes, structured electrolytes provide a promising alternate route to achieve high ionic conductivity and selectivity. In this perspective, we begin by describing the physical origins of the idealized liquid transport mechanism and then proceed to examine known cases of decoupling between the matrix dynamics and ionic transport in SPEs. Specifically we discuss conditions for "decoupled" mobility that include a highly polar electrolyte environment, a percolated path of free volume elements (either through structured or unstructured channels), high ion concentrations, and labile ion-electrolyte interactions. Finally, we proceed to reflect on the potential of these mechanisms to promote multivalent ion conductivity and the need for research into the interfacial properties of solid polymer electrolytes as well as their performance at elevated potentials.

Solid polymer electrolytes with hydrates for structural supercapacitors

Structural supercapacitors that simultaneously carry mechanical loads and store electrical energy show great promise to increase the functionality and efficiency of countless mobile systems. Current iterations of all structural supercapacitors use bi-continuous electrolytes with two phases that provide mechanical and electrochemical functions separately. Here we demonstrate a single-phase hydrate-based solid polymer electrolyte with improved multifunctionality. The new structural electrolyte composed of polyethylene terephthalate (PET) and lithium perchlorate trihydrate (LiClO4·3H2O) is created through mix-melting of PET and LiClO4 followed by controlled hydration of the salt. The bound water molecules in the hydrates significantly improve the ionic conductivity while retaining the high mechanical stiffness of the electrolyte, which reduces the trade-off between the two functions as in previous reports. The electrolyte with the optimal composition achieves a flexural modulus of 2.1 GPa with an ionic conductivity of 1.05 μS/cm. Moreover, the single-phase electrolyte exhibits a much better electrochemical interface with electrodes compared to other structural electrolytes. The interfacial capacitance measured with our electrolyte is the same order of magnitude as that tested with a liquid electrolyte. The creation of this electrolyte allows for the development of more efficient structural supercapacitors. The strategy of introducing bound solvent molecules to improve the ionic conductivity without sacrificing the mechanical properties of solid polymer electrolytes can also be used to develop better electrolytes for all-solid-state batteries.

Study on ionic conductivity, dielectric and electrochemical properties of solid polymer electrolyte for battery applications

Study on ionic conductivity, dielectric and electrochemical properties of solid polymer electrolyte for battery applications

Enhanced Properties of Solid Polymer Electrolytes by a Bilayer Nonwoven Pet/Nanofiber Pvdf Substrate for Use in All-Solid-State Lithium Metal Batteries

Enhanced Properties of Solid Polymer Electrolytes by a Bilayer Nonwoven Pet/Nanofiber Pvdf Substrate for Use in All-Solid-State Lithium Metal Batteries

Generating Innovative Solid Polymer Electrolyte Based on Melanin and Without Binder for High Energy Li Batteries

The goal of this investigation is connected with wishes to use the melanin for formulating the solid polymer electrolyte without the binder for Li batteries. Nature and properties of solid polymer electrolyte of the Li batteries is an important factor for ensuring the properties of Li batteries. For successful optimization the properties of Li batteries the following list includes the important requirements for the polymer electrolyte: high conductivity in wide operating temperature, chemical stability and no ignition at under high temperature - even more than 1000C, low impedance of interface between electrode and solid polymer electrolyte, special design of system - the solid polymer electrolyte in porous structure of electrode. For developing the solid polymer electrolyte without the binder we fulfill this goal includes the melanin in the solid polymer electrolyte.

Salt Concentration Effect on Electrical and Dielectric Properties of Solid Polymer Electrolytes based Carboxymethyl Cellulose for Lithium-ion Batteries

Solid polymer electrolytes (SPEs) based carboxymethyl cellulose (CMC) with lithium perchlorate (LiClO4) were prepared via solution drop-cast technique. The CMC host is complexed by different concentrations of LiClO4 salt. SPEs were characterized by Electrochemical Impedance Spectroscopy (EIS) and Linear Sweep Voltammetry (LSV) in coin cells with lithium metal electrodes. EIS performed unique results based on various ionic conductivity values and dielectric properties. The higher ionic conductivity (1.32 × 10-5 S/cm) was obtained by SPEs 2 following by short-range ionic transport results based on dielectric properties depending on frequency. SPEs with LiClO4 addition are electrochemically stable over 2 V in lithium battery coin cells from LSV results.

The Effects of Monosaccharides on the Physico-Electrochemical Properties of Chitosan Based Solid Polymer Electrolytes (SPES)

Monosaccharides have shown their potential as plasticizers in solid polymer electrolytes (SPEs) due to the presence of numerous hydroxyl (OH) functioning groups. Glucose and fructose were used in this study. The effect of monosaccharides on physico-electrochemical properties of solid polymer electrolytes based on chitosan have been studied. Chitosan-based polymer electrolytes have been successfully plasticized using a solution-casting technique at six different weight percentages (0-30 wt.%). The result shows that 15 wt.% was the highest ionic conductivity achieved by both chitosan-glucose (CG) and chitosan-fructose (CF) systems. Lithium transference number (TLi+) analysis showed that CF had a high number of lithium ions compared to the CG system, with values of 0.26 and 0.14, respectively. In addition, Linear Sweep Voltammetry (LSV) analysis shows that the electrochemical stability for the CG system was 2.98 V compared to 3.20 V for the CF system. This discovery demonstrates that monosaccharides have the potential to be used as plasticizers due to the presence of several oxygen atoms in the structure, which act as a coordination site for cation interaction and can also improve the ion mobility and ionic conductivity of chitosan-based solid polymer electrolytes.

Mechanical properties and interfacial compatibility of functionalized carbon nanotubes as fillers for chitosan solid polymer electrolytes

Fillers added to enhance the mechanical properties of solid polymer electrolytes (SPEs) should have excellent mechanical strength and good interfacial compatibility. Carbon nanotubes (CNTs) can meet these requirements because these not only have excellent mechanical strength but can also be functionalized to form chemical bonds with the host matrices. However, the two requirements are contradictory to each other; as the walls of CNTs are replaced with more functional groups to increase the number of chemical bonds, their mechanical strength decreases and vice versa. Thus, to maximize the advantages of CNTs, these should be functionalized at an appropriate level. Nevertheless, most studies have focused only on the functionalization of CNTs, and an increase in their interfacial compatibility. Herein, multi-walled carbon nanotubes (MWNTs) substituted with different concentrations of acid chloride were prepared and used as fillers for chitosan SPEs. Their mechanical properties were investigated to determine the optimum functionalization level of MWNTs, and their ionic conductivities were measured as a function of the glycerol (plasticizer) and lithium salt (dopant) amounts for potential applications in practical SPEs.

Impact of Negative Charge Delocalization on the Properties of Solid Polymer Electrolytes

AbstractThe nature of salt anion is of particular relevance in determining the features of solid polymer electrolytes (SPEs). Here, lithium salt containing an extremely delocalized anion (Li[CF3SO(=NSO2CF3)2], LisTFSI) is introduced into SPEs utilizing poly(ethylene oxide) (PEO) as a matrix, aiming to elucidate the role of negative charge delocalization on the properties of SPEs. In comparison with the reference Li[N(SO2CF3)2] (LiTFSI)/PEO electrolyte, LisTFSI/PEO shows higher lithium‐ion transference number and lithium‐ion‐only conductivity (i. e., the ionic conductivity contributed only by the lithium ions), owing to the improved flexibility and super‐delocalized negative charge of the −SO2N(−)−SO(=NSO2CF3)− structure in sTFSI− (vs. TFSI−). Moreover, the interphases of lithium metal electrode|SPE formed in LisTFSI/PEO show superior stability upon storage. These interesting properties of the LisTFSI/PEO system suggest that extending negative charge delocalization in sulfonimide anions is a powerful tool to improve the properties of SPEs.

Enhanced single-ion conduction and free-standing properties of solid polymer electrolyte by incorporating a polyelectrolyte

A free-standing solid polymer electrolyte (SPE) composed of poly(ethylene oxide) (PEO), bis(trifluoromethanesulfonyl)imide (LiTFSI), and poly(lithium 4-styrenesulfonate) (PLSS) was developed in this work. Thermal analysis indicated that the melting points of PEO were depressed with increasing the salt additives, LiTFSI and PLSS. At the composition of [EO]:LiTFSI:[LSS] = 14:1:1, the SPE exhibited a crystallinity of 7.75%, and a crystallite size of 30.62 nm on the (120) crystallographic plane. [EO] and [LSS] represent the structural unit of PEO and PLSS, respectively. This SPE also exhibited an ionic conductivity (σ) of 1.70 × 10−5 S cm−1 at 25 °C and 1.04 × 10−4 S cm−1 at 45 °C. For analyzing the temperature dependence of σ, the Vogel-Tammann-Fulcher equation was employed. Resultantly, a pseudo activation energy (E a = 0.1552 eV), a prefactor (A = 206.0338 S cm−1 K1/2), and an empirical constant (B = 1800.5879 K) were obtained using the optimized [EO]:[Li+] = 7:1 complex. The SPE showed an electrochemical stability window of ∼4.7 ± 0.1 V versus Li/Li+. Through DC polarization and AC impedance, the Li-ion transference number of 0.66 was obtained at 70 °C. Finally, when a Li/SPE/LiFePO4 cell was prepared, the device exhibited a discharge capacity of 121 mAh g−1 at 50 °C with a coulombic efficiency close to 100%.

Thermal and Electrochemical Properties of Solid Polymer Electrolytes Prepared via Lithium Salt-Catalyzed Epoxide Ring Opening Polymerization

Solid polymer electrolytes have been widely proposed for use in all solid-state lithium batteries. Advantages of polymer electrolytes over liquid and ceramic electrolytes include their flexibility, tunability and easy processability. An additional benefit of using some types of polymers for electrolytes is that they can be processed without the use of solvents. An example of polymers that are compatible with solvent-free processing is epoxide-containing precursors that can form films via the lithium salt-catalyzed epoxide ring opening polymerization reaction. Many polymers with epoxide functional groups are liquid under ambient conditions and can be used to directly dissolve lithium salts, allowing the reaction to be performed in a single reaction vessel under mild conditions. The existence of a variety of epoxide-containing polymers opens the possibility for significant customization of the resultant films. This review discusses several varieties of epoxide-based polymer electrolytes (polyethylene, silicone-based, amine and plasticizer-containing) and to compare them based on their thermal and electrochemical properties.

Study of the Electronic Properties of Solid Polymer Electrolytes Based on Blends of CMC, PEO, and Acetic Acid

The effect of blending on the electronic properties of sodium carboxymethyl cellulose (CMC) and polyethylene oxide (PEO) was studied theoretically using density functional theory (DFT). The CMC and PEO structures were first optimized individually, then were optimized at different blending ratios. All calculations were carried out at the B3LYB/3-21g* level of theory. The changes that occurred in the electronic properties of the individual polymers due to blending were presented in terms of total dipole moment (TDM), the electronic bandgap energy (HOMO/LUMO band gap), and molecular electrostatic potential (MESP). The results indicated that the blended structures were suitable for application in electrochemical devices as the TDM increased, HOMO/LUMO bandgap decreased, and electro-negativity increased. Also, it was concluded that the blended structures' electronic properties were also enhanced by the addition of small concentrations of acetic acid.

Electrical Properties Study of Solid Polymer Electrolyte based on PolyCaproLactone/LiCF3SO3 Added Plasticizer

The electrical properties of solid polymer electrolyte based on biodegradable polymer PolyCaproLactone (PCL)/LiCF3SO3 with PC plasticizer addition have been studied. Polymer electrolyte membranes were prepared by solution casting technique by varying propylene carbonate (PC) composition (0-60) % weight. The membranes were characterized by the Electrical Impedance Spectroscopy at room temperature to measure its ionic conductivity and other electrical properties such as dielectric constant and tangent loss. The PCL/LiCF3SO3 system containing 20% weight PC plasticizer exhibits the highest conductivity of 4.92 x 10−4 S/cm at room temperature. The dielectric constant shows decreases with frequency increasing and it depends on dissociation of ions in the polymer electrolyte system. The tangent loss suggests that there are relaxing dipoles in the polymer electrolyte that shift toward higher frequency region. The membrane microstructure also investigated by XRD and the result showed that the PC plasticizer made the PCL/LiCF3SO3 system become more amorphous

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).