Nanocomposite Solid Polymer Electrolytes Research Articles

Studies of the Properties of New Electrospun Based on PVA-PEG Polymer Systems Electrolytes for Energy Storage Devices

Solid polymer electrolytes (SPEs) have been considerably investigated due to various electrochemical device applications. Most of the SPEs comprise polymer as a host material to provide strength and good mechanical stability and salt that transfers charge carriers to cause conductivity. Nanocomposite solid polymer electrolyte membranes based on poly(vinyl alcohol) (PVA)-poly(ethylene glycol) (PEG) blend complexed with LiClO4 and nanofillers Al2O3 at different weight percent ratios have been obtained by using electrospinning method. The conductivity and structural properties of the different systems have been characterized by using various experimental approaches such as X-ray diffraction (XRD) and Fourier transform infrared FTIR spectroscopy. The ionic conductivity of the systems has been measured by using an LCR meter in a temperature ranging from 298 to 353 K. Maximum ionic conductivity of 1.58 × 10-4 S cm-1 at room temperature has been observed for the system of PVA-PEG-LiClO4-Al2O3 (50-25-15-10) with 15 wt% weight percent of LiClO4 salt in PVA-PEG blend matrix. The ac conductivity report indicates that the ionic conductivity of the PVA-PEG-LiClO4-Al2O3 complex is influenced by the concentration of LiClO4. The effect of temperature on the ionic conductivity of polymer electrolyte complexes has been estimated by changing the temperature ranging from 298 to 353 K. However, the conductivity of the nanofiber polymer electrolyte systems increases with the rise of temperature, and the maximum conductivity of 1.58 × 10-2 S cm-1 has been recorded at 353 K. The temperature-dependent conductivity follows the Arrhenius behavior.

Improving electrolyte performance: Nanocomposite solid polymer electrolyte films with cobalt oxide nanoparticles

AbstractThe present work gives an insight into the structural, thermal, and electrical analysis of novel nanocomposite solid polymer electrolyte films prepared using the solution casting technique by incorporating cobalt oxide nanoparticles into methyl cellulose‐magnesium acetate polymer electrolyte matrix. The impact of ceramic oxide on the complexation of the salt with the polymer chain is evident from FTIR analysis. The crystallinity of the electrolyte systems decreases upon the incorporation of nanofiller into the matrix. Electrochemical Impedance Analysis of the samples shows enhancement in the conductivity of the electrolytes. Nanocomposite electrolyte systems with 2 wt% (5.93 × 10−4 S/cm) and 3 wt% (5.77 × 10−4 S/cm) of cobalt oxide exhibit maximum room temperature ionic conductivity compared to other electrolyte systems. DSC thermogram reveals the creation of free volume in the matrix with the incorporation of the filler. A primary battery is fabricated using the nanocomposite electrolyte system with 3 wt% of the nanofiller, and its open circuit potential and discharge characteristics have been analyzed.Highlights Novel nanocomposite SPEs with cobalt oxide were prepared via solution casting. FTIR and XRD studies revealed modification in the microstructure. Cobalt oxide incorporation enhanced ionic conductivity of SPE. A primary battery fabricated using the highest conducting SPE.

Nanocomposite Solid Polymer Electrolytes with Polymer Blend (PVDF‐HFP/Pluronic) as Matrix and GO as Nanofiller: Preparation, Structural Characterization, and Lithium‐Ion Conductivity Analysis

AbstractNanocomposite solid polymer electrolytes (NSPEs) with PVDF‐HFP/Pluronic as blend polymer matrix, graphene oxide (GO) as nanofiller, and LiClO4 are reported. FTIR spectroscopy reveals the crystal phase transformation of PVDF‐HFP from nonpolar α phase to electroactive γ phase upon salt addition that suggests the ion‐dipole interaction between the salt and the matrix. Further, Pluronic not only hinders the PVDF crystallization that increases the amorphous character of the matrix but also interacts with the salt and hence assists in salt dissociation in the blend matrix. The dc conductivity of PVDF‐HFP/Pluronic/LiClO4 blend SPE improves with increasing the Pluronic content reaching 0.73 × 10−6 Scm−1 at room temperature with 60 wt.% Pluronic. The dispersion of GO in the same blend SPE leads to a significant jump in room temperature ion conductivity (≈1.2 × 10−6 Scm−1) with 0.4% GO. Temperature‐dependent ion conductivity of the NSPEs reveals an Arrhenius type thermally activated process. The dc polarization data indicates that the conductivity is predominantly due to ions. Impedance plots exhibit a distorted semicircle at higher frequency and a tilted spike at lower frequency. The spike is an indication of ion diffusion and electrode polarization effect. Further, GO also has enhanced the mechanical properties of the fabricated NSPEs.

Structural and Spectroscopic Investigation on Plasticized PEO/PMMA Blended Nanocomposite Solid Polymer Electrolytes

Structural and Spectroscopic Investigation on Plasticized PEO/PMMA Blended Nanocomposite Solid Polymer Electrolytes

Novel nanoarchitecture of 3D ion transfer channel containing nanocomposite solid polymer electrolyte membrane based on holey graphene oxide and chitosan biopolymer

In the arena of three-dimensional (3D) nanoarchitecture, holey graphene oxide (HGO)—a class of two-dimensional (2D) graphene oxide porous nanosheet, has emerged as a promising choice of additive material to design advanced 3D nanocomposite for energy and environmental applications. With a facile and cost-effective solution-casting technique, we fabricated here a flexible, wearable, free-standing, and super-thin (∼0.08 mm) solid polymer electrolyte membrane (SPEM) consisting of 2D-HGO, lithium bis(trifluromethanesulfonyl)imide (LiTFSI) salt, polyvinylpyrrolidone (PVP) polymer binder, and chitosan (CH) biopolymer. SPEM exhibited impressive ionic conductivity of 2.76 × 10-3 S⋅cm−1 at room temperature (RT = 23 °C) which is comparable to liquid electrolytes. Robust mechanical property (5.87 MPa) and easy lithium-ion diffusion capability of SPEM were identified by the ultra-low activation energy (Ea) of 0.089 eV, which is one of the best values among the reported solid polymer electrolytes. Good lithium-ion transference number (tLi+= 0.76) and wide electrochemical stability window (ESW = 4.4) indicated single ion conduction and stable battery operation voltage capability of SPEM. Moreover, fast ion transfer mechanism of SPEM was proposed according to the comprehensive characterizations; mostly relating to uniform and strong interconnecting novel 3D ion transferring routes. Temperature and frequency responsive charge carrier mobility trend were also investigated with an in-depth dielectric study. Promising RT galvanostatic Li plating-stripping performance was observed at 5 mA⋅cm−2 with a hybrid symmetric cell. Using Li metal as anode, SPEM, and LiCoO2 as cathode in the full cell, a good RT specific discharge capacity of 142.8 mA⋅h⋅g−1 was achieved at 0.1 C rate.

Graphene Oxide-Grafted Hybrid Diblock Copolymer Brush (GO-graft-PEG6k-block-P(MA-POSS)) as Nanofillers for Enhanced Lithium Ion Conductivity of PEO-Based Nanocomposite Solid Polymer Electrolytes.

Nanocomposite solid polymer electrolytes (NSPEs) with PEO as the matrix and (i) GO or (ii) GO-graft-PEG6k or (iii) GO-graft-PEG6k-block-P(MA-POSS) as nanofillers have been fabricated to elucidate the impact of the filler morphology on the lithium ion conductivity. GO-graft-PEG6k was obtained by grafting PEG6k onto GO via esterification. GO-graft-PEG6k-block-P(MA-POSS) was prepared via surface-initiated atom transfer radical polymerization. Fourier-transform infrared spectroscopy revealed enhanced salt dissociation and complexation between the filler and PEO host that could be attributed to Lewis acid-base interactions. Electrochemical impedance spectroscopy revealed the improved ion conductivity of the fabricated NSPEs as compared with the pristine PEO-LiClO4. As an example, at 50 °C, the ion conductivity increased to 4.01 × 10-5 and 6.31 × 10-5 S cm-1 with 0.3% GO and 0.3% GO-graft-PEG6k, respectively, from 2.36 × 10-5 S cm-1 of PEO-LiClO4, suggesting that the filler with brush-like architecture (GO-graft-PEG6k) is more efficient in enhancing the ion conductivity. Further increase in filler content resulted in lowering of the ion conductivity that could be ascribed to aggregation of the filler. The most dramatic impact on conductivity was observed with the incorporation of brush-like GO-graft-PEG6k-block-P(MA-POSS) as a nanofiller (3.0 × 10-4 S cm-1 at 50 °C with 1.0 wt % filler content). The increase in ion conductivity in the current systems, as opposed to the conventional view, could not be correlated with the content of the amorphous phase of the matrix. The conduction mechanism is still unclear; nevertheless, it could be assumed that in addition to the ion conduction through the PEO matrix, the filler forms additional low-energy ion conducting channels at its interface with the matrix. The pendent POSS nanocages of GO-graft-PEG6k-block-P(MAPOSS) might probably increase the free volume at the interface with the matrix that is associated with higher chain and ion mobility, thus further enhancing the ion conductivity as compared with GO and GO-graft-PEG6k. The faster ion dynamics in 1.0 wt % GO-graft-PEG6k-block-P(MAPOSS) NSPEs has also been verified by the dielectric relaxation studies. Thus, integration of both the PEG and POSS nanocages into GO-grafted brush-like architecture offers a new tool for tuning the lithium ion conductivity for potential Li ion battery applications.

Towards advanced lithium metal solid-state batteries: Durable and safe multilayer pouch cell enabled by a nanocomposite solid electrolyte

Lithium metal solid-state batteries (SSBs) are expected to outperform the current lithium-ion battery technology, limited by the performance, energy density, and safety issues. One of the most promising classes of solid electrolytes for SSBs are polymer-inorganic composites. However, incompatibility between inorganic and polymer phases may affect the solid electrolyte properties and, therefore, the SSB performance. Therefore, in this study, novel nanocomposite solid polymer electrolytes (nCSPE), containing inert alumina nanoparticles with specially customized interface, are successfully synthesized. Thermal, mechanical, electrical and electrochemical properties of the prepared nCSPEs are evaluated to select the most promising solid electrolyte formulation for its further scale-up. Afterwards, multilayer solid state pouch-type cells with a nominal capacity of ca. 0.5 Ah are successfully prepared, using the developed nCSPE, current-collector-free thin Li metal anode, and double-sided composite LiFePO4 cathode. “Li/nCSPE/LiFePO4” prototype pouch cells are cycled at 60 °C, exhibiting long cycle life with more than 2000 cycles with a high coulombic efficiency, and enhanced safety in the fully charged state. This research could contribute to promising advances on the development of new generation of high performant and safe Li metal SSBs.

TiO2 Added PMMA : PVDF-HFP : NaClO4 Nanocomposite Solid Polymer Electrolyte and Its Application in Dye Sensitized Solar Cell

TiO2 Added PMMA : PVDF-HFP : NaClO4 Nanocomposite Solid Polymer Electrolyte and Its Application in Dye Sensitized Solar Cell

Substantial Proton Ion Conduction in Methylcellulose/Pectin/Ammonium Chloride Based Solid Nanocomposite Polymer Electrolytes: Effect of ZnO Nanofiller

In this research, nanocomposite solid polymer electrolytes (NCSPEs) comprising methylcellulose/pectin (MC/PC) blend as host polymer, ammonium chloride (NH4Cl) as an ion source, and zinc oxide nanoparticles (ZnO NPs) as nanofillers were synthesized via a solution cast methodology. Techniques such as Fourier transform infrared (FTIR), electrical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) were employed to characterize the electrolyte. FTIR confirmed that the polymers, NH4Cl salt, and ZnO nanofiller interact with one another appreciably. EIS demonstrated the feasibility of achieving a conductivity of 3.13 × 10−4 Scm−1 for the optimum electrolyte at room temperature. Using the dielectric formalism technique, the dielectric properties, energy modulus, and relaxation time of NH4Cl in MC/PC/NH4Cl and MC/PC/NH4Cl/ZnO systems were determined. The contribution of chain dynamics and ion mobility was acknowledged by the presence of a peak in the imaginary portion of the modulus study. The LSV measurement yielded 4.55 V for the comparatively highest conductivity NCSPE.

Nanoarchitecture of Novel 3D Ion Transferring Channel Containing Composite Solid Polymer Electrolyte Membrane Based on Holey Graphene Oxide and Chitosan Biopolymer

In three-dimensional (3D) nanoarchitecture arena, two-dimensional (2D) nanostructured graphene oxide (GO) and its derivatives have been emerged as a promising choice of advanced additive materials due to their outstanding properties: high specific surface area (2630 m2g-1), flexibility, light weight, diverse functionality, super mechanical and thermal stability. Particularly, holey graphene oxide (HGO)—single atom thick unique 2D porous nanosheet is obtained from exfoliation of functional GO—a class of graphene sheet with abundant nanopore in their plane; can potentially be used for designing, fabricating and evaluating advanced 3D nanocomposite materials for the development of demandable renewable energy technologies including next generation of solid-state Li+ and Na+ rechargeable batteries. Having been the most significant, momentous, and effectual commercial energy storage devices over the past decade, however, lithium-ion batteries (LIBs) have some key limitations: flammability, poor thermal, and mechanical stability. To overcome these existing limitations, incorporation of ceramic or polymer-based solid-state electrolytes into the LIBs are being explosively focused by the energy storage research community because of their full solid-state condition and tunable molecular level engineering scope.In this research work, a novel 3D nanocomposite solid polymer electrolyte membrane (SPEM) has been successfully developed based on 2D-HGO and chitosan (CH) biopolymer—naturally occurring only alkaline polysaccharide obtained from industrial shrimp shells, super cheap, nanostructured, non-toxic, completely biodegradable, also abundant in nature. In addition, a facial and cost-effective solution-casting technique has been utilized to fabricate SPEM and applied as a solid-state polymer electrolyte for next generation of flexible and wearable rechargeable LIB technology. To investigate the structural, morphological, thermal, mechanical, and electrochemical performance of as prepared SPEM, so far, a comprehensive characterization has been done with the help of SEM, TEM, XRD, TGA, DSC, FTIR, Raman, elemental analysis, tensile strength test, and electrochemical impedance spectroscopy techniques. The SEM analysis of as-prepared flexible, wearable, free-standing, and super thin (~0.08 mm) SPEM depicts the coherently aligned 2D-HGO nanosheets formed a uniform and strong interconnecting 3D ion transfer channels with the host CH biopolymer. Moreover, 1wt% HGO, almost evenly distributed nanofiller SiO2 particles along with polyvinylpyrrolidone (PVP) polymer binder played an important role to generate better mechanical and electrochemical properties in SPEM. Thus, SPEM exhibited impressive ionic conductivity (6.44 x 10-3 Scm-1 at 23.1 oC and 1.02×10-2 Scm-1 at 70oC), a high level of tensile strength (5.87 MPa) as well as 672% and 93.7% increase of tensile strength than that of without HGO additive and GO based nanocomposite membranes respectively. In fact, very low activation energy (Ea = 0.08 eV) value shows the approval of easy lithium-ion diffusion capability in the SPEM system. In addition, fast ion transfer mechanism in SPEM has been investigated with an in-depth dielectric study that tells us the mainly hopping mechanism is dominating in the novel 3D architecture of SPEM. Besides, the obtained impressive electrochemical and mechanical properties of as-prepared SPEM could assist to understand the further fundamental aspects and impacts of SPEM in the application of LIB technology.

Electrical Conductivity Properties of Solid Polymer Electrolytes PEO-PVP-NaIO4 Filled with TiO2 Nanoparticles

Frequency-dependent conductivity and conduction relaxation in nanocomposite solid polymer electrolyte films consisting of poly(ethylene oxide) and polyvinyl pyrrolidone blend as host matrix, NaIO4 as ions dopant, and titanium dioxide (TiO2) nanoparticles of average size 10 nm, were studied. The films were characterized using measurements of complex electrical impedance spectra in the frequency range from 1 Hz to 1 MHz, at room temperature. The concentration of the salt NaIO4 was 10 wt%, the TiO2 percentage varied from 1 wt% to 5 wt%. The frequency spectra of both alternating-current (AC) conductivity and electric modulus were analyzed in order to elucidate the effect of TiO2 nanoparticles on the electrical transport properties of the examined electrolyte thin films with a thickness of 150 μm.

Ternary metal oxide filled PEO-based polymer electrolyte for solid-state lithium metal battery: The role of filler particle size

Composite polymer electrolytes with fillers exhibit appealing properties, such as high ionic conductivity, good flexibility, and low cost. However, poor compatibility and electrochemical instability, especially at high current rates, are the disadvantages of these electrolytes. In this study, we report the influence of particle size of Li2O. SiO2. TiO2. P2O5 (LSTP) on polyethylene oxide (PEO)-matrix towards the fabrication of Li-metal batteries with a LiFePO4 cathode. Compared to micron-sized particles, the high surface area of the nanoparticles in the polymer matrix is beneficial for improved electrochemical stability at 0.1 mA cm−2. Furthermore, the nanosized particulates facilitate faster ionic conductivity (1.09 × 10−3 S cm−1 at 80 °C) and excellent stability at higher voltage >4.5 V. Our results clearly indicate the role of filler morphology in enhancing the ionic conductivity and stability. Finally, the full cell made of metallic Li anode and LiFePO4 cathode displays a capacity of 110 mAh g−1 (after 100 cycles under 1C at 60 °C) with a reasonable cycle life using such a nanocomposite solid polymer electrolyte.

Ion Conductivity of Nanocomposite Solid Polymer Electrolyte PEO-PVP-NaIO4 with Added TiO2 Nanoparticles

We studied the effect of titanium dioxide (TiO2)nanoparticles (NPs)on ion conductivity of Na+ ion-conducting nanocomposite solid polymer electrolyte (NCSPE) composed of polymers poly(ethylene oxide) (PEO) and polyvinyl pyrrolidone (PVP), sodium metaperiodate (NaIO4)at concentration 10 wt%, and with added TiO2NPs of average size ∼ 10 nm at concentration from 1 wt% to 5 wt%. The electrical response of thin films (150μm) of PEO/PVP/NaIO4/TiO2 was characterized by employing the complex electrical impedance spectroscopy. The changes in ion-conducting properties of the examined NCSPEs induced from the included TiO2 NPs, were explained.

Impedance spectroscopy and electrochemical cell studies of Mg+2 ion conducting with dispersed ZrO2 nano filler in PVDF-HFP based nano composite solid polymer electrolytes

Nano composite polymer electrolytes with different concentrations of ZrO2 nanofillers added in PVDF-HFP:Mg(ClO4)2are prepared using classical solution casting technique.The incorporation of ZrO2 nanofillers into the PVDF-HFP: Mg(ClO4)2improved conductivity by making more ions available for conduction. Electrochemical Impedance Spectroscopy was used to investigate the electrical conductivity, ohmic resistance(RΩ), polarisation resistance(Rp), and Warburg impedance W to understand ion transportation behaviour. And the composition-dependent ionic conductivity was determined and the optimum found σion=6.62×10-2SCm-1 at the PSZr12. The nanocomposite polymer electrolyte is used to prepare an electro chemical cell, and its open circuit voltage is found to be1.8 V and its short circuit current is 180 mA.

Structure and Dynamics in Self-Healing Polymer Electrolytes Based on PVDF-HFP for Battery Applications

Lithium dendrite formation is a key limitation in rechargeable Li metal batteries. Here we report on a novel polymer electrolyte with self-healing capabilities, consisting of PVdF-HFP membranes imbibed with an ionic liquid electrolyte EMIM-TFSI + LiTFSI and mechanically reinforced by alumina nanowires. Similar membranes were reported to have self-healing capability via resistance to dendrite formation at the electrode-electrolyte interface.1 We have investigated the structure and dynamics in these membranes by nuclear magnetic resonance (NMR). Double resonance and 2D NMR methods show that the EMIM cation interacts with CF3 group present in HFP, forming an ion-dipole association which may be related to the desired self-healing properties. Moreover, addition of alumina nanowires has been reported2 to increase the ionic conductivity in the membrane in addition to imparting mechanical strength. We have used pulsed field gradient (PFG) NMR to investigate how alumina nanowire doping into the PVDF-HFP-IL matrix improves the Li+ diffusivity. Additional characterizations such as electron dispersion X-ray (EDX) spectroscopy to study nanowire distribution in the polymer and ionic conductivity measurements, will also be discussed. Keywords: Ionic Liquids, Self-healing, Dendrite formation, PVDF-HFP membranes, NMR spectroscopy, EDX References Chen, T. et al. Ionic liquid-immobilized polymer gel electrolyte with self-healing capability, high ionic conductivity and heat resistance for dendrite-free lithium metal batteries. Nano Energy 54, 17–25 (2018).Kwon, S. J. et al. Influence of Al2O3 Nanowires on Ion Transport in Nanocomposite Solid Polymer Electrolytes. Macromolecules 51, 10194–10201 (2018).

Effect of ZnO Nanoparticle Content on the Structural and Ionic Transport Parameters of Polyvinyl Alcohol Based Proton-Conducting Polymer Electrolyte Membranes.

Proton conducting nanocomposite solid polymer electrolytes (NSPEs) based on polyvinyl alcohol/ammonium nitrate (PVA/NH4NO3) and different contents of zinc oxide nanoparticles (ZnO-NPs) have been prepared using the casting solution method. The XRD analysis revealed that the sample with 2 wt.% ZnO-NPs has a high amorphous content. The ionic conductivity analysis for the prepared membranes has been carried out over a wide range of frequencies at varying temperatures. Impedance analysis shows that sample with 2 wt.% ZnO-NPs has a smaller bulk resistance compared to that of undoped polymer electrolyte. A small amount of ZnO-NPs was found to enhance the proton-conduction significantly; the highest obtainable room-temperature ionic conductivity was 4.71 × 10−4 S/cm. The effect of ZnO-NP content on the transport parameters of the prepared proton-conducting NSPEs was investigated using the Rice–Roth model; the results reveal that the increase in ionic conductivity is due to an increment in the number of proton ions and their mobility.

Nanocomposite polymer electrolytes comprising starch-lithium acetate and titania for all-solid-state supercapacitor

A nanocomposite solid polymer electrolyte (SPE) system has been prepared for application in a supercapacitor. Corn starch is used to host the ionic conduction with lithium acetate (LiOAc) salt as an ion provider. Different concentrations of nanosized titanium dioxide (TiO2) filler have been added to analyse the influence of nanofiller addition on the conductivity and other properties of the electrolytes. Structural characterisation and complex formation have been examined by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, respectively. It is shown that the room temperature conductivity changes with the change in TiO2 concentration. Adding 4 wt.% TiO2 to the starch-LiOAc complex leads to an optimum conductivity of (8.37 ± 1.04) × 10−4 S cm−1. The variation in conductivity is accompanied by the change in surface morphology as observed from field emission scanning electron microscopy (FESEM) analysis. Linear sweep voltammetry (LSV) indicates that the electrochemical potential stability window of the electrolyte with 4 wt.% TiO2 lies in the range between − 2.0 and + 1.9 V. A supercapacitor has been assembled using the electrolyte, and its performance has been characterised using impedance technique and cyclic voltammetry.

Free-standing, high Li-ion conducting hybrid PAN/PVdF/LiClO4/Li0.5La0.5TiO3 nanocomposite solid polymer electrolytes for all-solid-state batteries

The free-standing PAN/PVdF/LiClO4/Li0.5La0.5TiO3 nanocomposite solid polymer electrolytes have been prepared by solution casting technique. The thermal stability of composite solid polymer electrolytes is evaluated by TG/DSC analysis, which reveals that the filler incorporated composite samples exhibit high thermal stability up to 500 °C. The XRD analysis demonstrated that the Li0.5La0.5TiO3 nanoparticles significantly reduced the crystallinity of the hybrid PAN/PVdF/LiClO4 polymer films. The FTIR spectra of PAN/PVdF/LiClO4/Li0.5La0.5TiO3 composites show the vibrational band of –CN stretching, CF2 asymmetric stretching, and Ti-O-La stretching which confirmed the complexation between polymer host matrices and Li0.5La0.5TiO3 nanoparticles. The 10 wt% Li0.5La0.5TiO3 nanoparticles embedded PAN/PVdF/LiClO4 solid polymer electrolyte possessed an excellent ionic conductivity of 1.43 × 10−3 S cm−1 at room temperature, which is far better than the filler-free samples (~ 10−5 S cm−1). The incorporation of Li0.5La0.5TiO3 nanoparticles into the PAN/PVdF/LiClO4 polymer electrolyte improves the concentration of free mobile lithium ions and develops Li-ion conduction channels within the crystalline framework. The PAN/PVdF/LiClO4/Li0.5La0.5TiO3 (10 wt%) composite electrolyte exhibited high thermal stability, good discharge capacities of 122, 105, 94, and 80 mAh g−1 at 0.1, 0.5, 1, and 2C rates, and good cycling stability.

Nanocomposite solid polymer electrolytes based on semi-interpenetrating hybrid polymer networks for high performance lithium metal batteries

This research reports the synthesis of nanocomposite solid polymer electrolytes (ncSPEs) for solid state lithium metal batteries. These materials are composed of a controlled hybrid organic-inorganic network of glycidyl POSS® and Jeffamine® ED2003, in which linear high molecular weight poly (ethylene oxide) (PEO) chains are entangled to improve both mechanical and electrochemical properties of the ncSPE. Synthesis and preparation of self-standing membranes are achieved with a facile one-pot catalyst-free method with considerably reduced amount of organic solvent, which is a plus toward a future scale-up. We found that the component ratio plays a crucial role in ncSPEs’ performance as a simple variation (i.e. cross-linking degree) is sufficient to completely change the electrochemical behavior of the solid state cell. For instance, increasing POSS® amount guarantees better resistance to lithium dendrites penetration, better electro-oxidation stability, and significantly extends cycle life in Li/ncSPE/LiFePO4 solid state cells. Furthermore, besides improving cell performance at higher C-rate of Li/LiFePO4 cells, this PEO-based ncSPE gives better response than reference PEO-LiTFSI electrolyte in high voltage Li/LiNi0.6Mn0.2Co0.2O2 cells with up to 10 cycles at 60 °C with discharge capacity retention above 80%. Despite the poor performance, to the best of our knowledge, this electrolyte is one of the few examples of PEO-based solid polymer electrolytes being capable of cycling with high voltage cathodes.

Dielectric polarization and relaxation processes of the lithium-ion conducting PEO/PVDF blend matrix-based electrolytes: effect of TiO2 nanofiller

The effect of TiO2 nanofiller concentration on the dielectric polarization and relaxation processes of (75PEO/25PVDF)/25 wt% LiClO4–x wt% TiO2 (x = 0, 2, 5, 10, 15, and 20) compositions based nanocomposite solid polymer electrolyte (NSPE) films has been investigated by employing the dielectric relaxation spectroscopy. The SEM micrographs demonstrate that the dispersion of TiO2 nanoparticles enormously alters the spherulitic morphology with the development of some cracks, pores, and wrinkles of these solution-cast prepared NSPE films. The X-ray diffraction study confirms that the heterostructures of these NSPE materials are semicrystalline and their degree of crystallinity increases irregularly with the increase of TiO2 concentration, however the crystallinity of host polymer blend matrix of these electrolytes decreases. The complex dielectric permittivity spectra of these NSPE materials in the frequency range from 20 Hz to 1 MHz at 27 °C reveal that there is a dominant contribution of electrode polarization and interfacial polarization at lower frequencies, whereas the high frequency permittivity values attribute to dipolar and ionic polarizations. Four types of relaxation processes have been probed by the ‘master curve representation’ of the dielectric and electrical spectra of these solid ion–dipole complexes. It is observed that the addition of TiO2 nanoparticles up to 10 wt% in these electrolytes influences the dielectric properties anomalously, but a huge decrease in the dielectric polarization and increase in the relaxation times are noted resulting in a significant decrease in the ionic conductivity of the film at 20 wt% TiO2 concentration. The dependence of dc ionic conductivity of these lithium-ion conducting NSPE materials on the chain segmental relaxation time and also the degree of crystallinity has been explored. The results of these NSPE materials have also been compared with the TiO2 nanoparticles loaded different polymer matrices and salts based electrolytes and discussed appropriately. These lithium-ion based electrolyte films are accredited for the solid-state ion-conducting energy storing devices from their electrochemical parameters characterized by LSV, CV, and CA techniques.