Characteristics of PVdF‐HFP/TiO2 Composite Electrolytes Prepared by a Phase Inversion Technique Using Dimethyl Acetamide Solvent and Water Non‐Solvent

Summary: Highly porous poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (PVdF‐HFP)/TiO₂ membranes were prepared by a phase inversion technique, using dimethyl acetamide (DMAc) as a solvent and water as a non‐solvent. Their physical and electrochemical properties were then characterized in terms of thermal and crystalline behavior, as well as ionic conductivity after absorbing an electrolyte solution of 1 M LiPF₆ dissolved in an equal weight mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC). For comparison, cast films and their electrolytes were also made by a conventional casting method without using the water non‐solvent. In contrast to the case of using N‐methyl‐2‐pyrrolidone (NMP) as a solvent, the PVdF‐HFP/TiO₂ composite electrolytes, obtained using DMAc, exhibited superior properties of electrochemical stability and interfacial resistance with a lithium electrode but had lower ionic conductivities. It was also demonstrated that the phase inversion membrane was more effective than the cast film as the polymer electrolyte of a lithium rechargeable battery. As a result, a phase inversion membrane with 50 wt.‐% TiO₂ was demonstrated to be the optimal choice for application in a lithium rechargeable battery.

Time evolutions of interfacial resistance between polymer electrolyte and lithium electrodes.     

High performance electrospun PVdF‐HFP/SiO2 nanocomposite membrane electrolyte for Li‐ion capacitors

Electrospun poly[(vinylidene fluoride)‐co ‐hexafluoropropylene]/silica (PVdF‐HFP/SiO₂) nanocomposite polymer membranes (esCPMs) were prepared by incorporating different weight percentages of SiO₂ nanoparticles onto electrospun PVdF‐HFP by electrospinning technique. The surface morphology of electrospun PVdF‐HFP nanocomposite membranes was characterized by scanning electron microscopy. The effect of SiO₂ nanoparticles incorporation onto electrospun PVdF‐HFP polymer membranes (esPMs) has been studied by XRD, DSC, TGA, and tensile analysis. The electrospun PVdF‐HFP/SiO₂ based nanocomposite membrane electrolytes (esCPMEs) were prepared by soaking the corresponding esCPMs into 1 M LiPF₆ in EC:DMC (1:1 vol/vol %). The ionic conductivity of the esCPMEs was studied by AC‐impedance studies and it was found that the incorporation of SiO₂ nanoparticles into PVdF‐HFP membrane has improved the ionic conductivity from 1.320 × 10^?3 S cm^?1 to 2.259 × 10^?3 S cm^?1. The electrochemical stability of the esCPME was studied by linear sweep voltammetry studies and it was found to be 2.87 V. Finally, a prototype LiCo_0.2Mn_1.8O₄//C Li‐ion capacitor (LIC) cell was fabricated with esCPME, which delivered a discharge capacitance of 128 F g^?1 at the current density of 1 A g^?1 and retained 86% of its discharge capacitance even after 10,000 cycles. These results demonstrated that the esCPMEs could be used as promising polymer membrane electrolyte for LICs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45177.     

Characteristics of PVdF-HFP/TiO2 composite membrane electrolytes prepared by phase inversion and conventional casting methods

Porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)-based polymer membranes filled with various contents of titania (TiO₂) nanocrystalline particles are prepared by phase inversion technique and, along with conventional casting method for comparison. N-methyl-2-pyrrolidone (NMP) as a solvent is used to dissolve the polymer and to make the slurry with TiO₂. Cast film is obtained by spreading the slurry and evaporating NMP in a dry oven, while phase inversion membrane by promptly immersing the spread slurry into flowing water as a non-solvent. Physical and electrochemical characterizations, such as morphology, thermal and crystalline behavior, and other transport properties of lithium ionic species, are carried out for the polymer films/membranes and the polymer electrolytes with absorbing an electrolyte solution. Phase inversion polymer electrolytes are proved to show superior behaviors in electrochemical properties, such as ionic conductivity, electrochemical and interfacial stability, than cast film electrolytes. This is greatly owed to highly porous structure of phase inversion membranes. Even including the feature of interfacial resistance with lithium electrode, phase inversion polymer electrolytes of PVdF-HFP/(5-20 wt.% TiO₂) can be optimized as the adequate ones in applying to the electrolyte medium of lithium rechargeable batteries.     

Development of a conjugated polyaniline incorporated electrospun poly(vinylidene fluoride‐co‐hexafluoropropylene) composite membrane electrolyte for high performance dye‐sensitized solar cells

Different weight percentage (2, 3, 4, and 5 wt %) of polyaniline (PANI) were incorporated into electrospun poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) composite membranes (esCPMs). The regular morphology, molecular structure, crystallinity, porosity, electrolyte uptake, and leakage of the composite membranes were examined. The esCPMs were activated in liquid electrolyte containing 0.5 M LiI, 0.05 M I₂, and 0.5 M 4‐tert‐butylpyridine and 0.5 M 1‐butyl‐3‐methylimidazoliun iodide in acetonitrile to afford electrospun PVdF‐HFP/PANI composite membrane electrolytes (esCPMEs). The influence of different wt % of PANI on the esCPMEs was studied by electrochemical impedance measurements and Tafel polarization studies. The photovoltaic performance of a dye‐sensitized solar cell assembled using 3 wt % PANI incorporated esCPME exhibits a higher power conversion efficiency of 7.20% than that assembled using esPME (η = 6.42%). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42777.     

Lewis acid–base property of P(VDF‐co‐HFP) measured by inverse gas chromatography

Poly (vinylidene fluoride‐co‐hexafluoropropylene) P(VDF‐co‐HFP) is an excellent material for polymer electrolytes of lithium ion battery. To enhance the lithium ion transference number, some metal oxides were often embedded into P(VDF‐co‐HFP). The promising mechanism for the increase in lithium ionic conductivity was Lewis acid‐base theory. In this experiment, the Lewis acid–base properties of P(VDF‐co‐HFP) were measured by inverse gas chromatography (IGC). The Lewis acid constant K_a of P(VDF‐co‐HFP) is 0.254, and the base constant K_b is 1.199. Compared with other polymers characterized by IGC, P(VDF‐co‐HFP) is the strongest Lewis basic polymers. Except aluminum ion, lithium ion is the strongest Lewis acidic ion according to their η value of Lewis acids. Therefore, a strong Lewis acid–base interaction will exist between lithium ion and P(VDF‐co‐HFP). This will restrict the transference of lithium ion in P(VDF‐co‐HFP). To enhance the lithium ion transference by blending other metal ions into P(VDF‐co‐HFP), it is suggested that the preferential ions should be Al³⁺, Mg²⁺, Na⁺, and Ca²⁺ because these metal ions have relative large η values. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of various electrophoretically deposited nano‐silica contents on the properties of poly(vinylidene fluoride‐co‐hexafluoropropylene)‐based electrospun polymer electrolytes

Poly(vinylidene fluoride‐co‐hexafluoropropylene) (P(VDF‐HFP)) based composite polymer electrolyte (CPE) membranes were successfully prepared by electrospinning followed by electrophoretic deposition processes, and desirable polymer electrolytes were obtained after being activated in liquid electrolytes. The physicochemical properties of the CPEs with different electrophoretically deposited nano‐SiO₂ contents were investigated by SEM, XRD, TGA, linear sweep voltammetry and electrochemical impedance spectroscopy measurements. When the ratio of electrophoretically deposited nano‐SiO₂ to P(VDF‐HFP) is up to 4 wt%, the results show that the CPE membrane presents a very uniform surface with abundant interconnected micropores and possesses excellent mechanical tensile strength with high thermal and electrochemical stability; the ionic conductivity at room temperature can reach 3.361 mS cm^?1 and the reciprocal temperature dependence of the ionic conductivity follows a Vogel ? Tamman ? Fulcher relationship. The interfacial resistance of the assembled Li/CPE/Li simulated cell can rapidly increase to a steady value of about 950 Ω from the initial value of about 700 Ω at 30 °C during 15 days' storage. The battery performance test suggests that the CPE also shows excellent compatible properties with commercial LiCoO₂ and graphite materials. © 2015 Society of Chemical Industry     

Preparation and performance study on P(St‐MMA)‐SiO2 doped P(VDF‐HFP) based composite polymer electrolyte

The organic–inorganic hybrid material poly(styrene‐methyl methacrylate)‐silica (P(St‐MMA )‐SiO₂) was successfully prepared by in situ polymerization confirmed by Fourier transform infrared spectroscopy and was employed to fabricate poly(vinylidene fluoride‐hexafluoropropylene) (P(VDF‐HFP )) based composite polymer electrolyte (CPE ) membrane. Desirable CPEs can be obtained by immersing the CPE membranes into 1.0 mol L^?1 LiPF₆‐EC /DMC /EMC (LiPF₆ ethylene carbonate + dimethyl carbonate + ethylmethyl carbonate) liquid electrolyte for about 0.5 h for activation. The corresponding physicochemical properties were characterized by SEM , XRD , electrochemical impedance spectroscopy and charge–discharge cycle testing measurements. The results indicate that the as‐prepared CPEs have excellent properties when the mass ratio of the hybrid P(St‐MMA )‐SiO ₂ particles to polymer matrix P(VDF‐HFP ) reaches 1:10, at which point the SEM analyses show that the as‐prepared P(St‐MMA )‐SiO ₂ particles are uniformly dispersed in the membrane and the CPE membrane presents a homogeneous surface with abundant interconnected micropores. The XRD results show that there may exist interaction forces between the P(St‐MMA )‐SiO ₂ particles and the polymer matrix, which can obviously decrease the crystallinity of the composite membrane. Moreover, the ionic conductivity at room temperature and the electrochemical working window of the CPE membrane can reach 3.146 mS cm^?1 and 4.7 V, respectively. The assembled LiCoO₂/CPE /Li coin cell with the CPE presents excellent charge–discharge and C ‐rate performance, which indicates that P(St‐MMA )‐SiO ₂ hybrid material is a promising additive for the P(VDF‐HFP ) based CPE of the lithium ion battery. © 2016 Society of Chemical Industry     

Properties on novel PVDF‐HFP‐based composite polymer electrolyte with vinyltrimethoxylsilane‐modified ZSM‐5

A kind of novel poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP)‐based composite polymer electrolyte doped with vinyltrimethoxylsilane (DB171 silane)‐modified ZSM‐5 is prepared by phase inversion method (denoted as M‐ZSM‐5 membrane). Physical and chemical properties of M‐ZSM‐5 membrane are studied by SEM, FTIR, TG‐DSC, EIS, and LSV. The results show that thermal and electrochemical stability can reach 400°C and 5 V, respectively; temperature dependence of ionic conductivity follows Vogel–Tamman–Fulcher relation and ionic conductivity at room temperature is up to 4.2 mS/cm; the interfacial resistance reaches a stable value about 325 Ω after 5 days storage at room temperature, which suggests that it can be potentially suitable as electrolyte in polymer lithium ion battery. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers     

Synthesis and characterization of LiBOB‐based PVdF/PVC‐TiO2 composite polymer electrolytes

Synthesis and characterization of composite polymer electrolytes based on lithium bis(oxalato)borate (LiBOB) and a host matrix of nanoparticulate anatase dispersed in phase‐separated poly(vinylidenefluoride) (PVdF)‐poly(vinylchloride) (PVC) are described. Ethylene carbonate (EC) and diethyl carbonate (DEC) were used as plasticizers in the membranes, and nanoparticulate TiO₂ (anatase) was used as the filler. The membranes were characterized by SEM, XRD, and a.c. impedance measurements. A membrane with 2.5 wt% filler exhibited a conductivity of 5.43 × 10^?4 S.cm^?1 at ambient temperature. Filler levels above 2.5 wt% increased the crystallinity of the membranes, rendering them less conducting. Activation energy and coherent length of the composite polymer electrolytes have also been calculated. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers.     

Preparation and properties of cross‐linked poly(ethylene glycol)/poly[(vinylidene fluoride)‐co‐hexafluoropropylene] interpenetrating network‐type electrolytes for secondary lithium batteries

Cross‐linked poly(ethylene glycol)/poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (XPEG/PVDF–HFP) gel‐type polymer electrolyte interpenetrating polymer networks (IPNs) were prepared by cross‐linking the PEG molecules in the presence of PVDF–HFP molecules. Thermal, mechanical, swelling and electrochemical properties, as well as microstructures of the prepared polymer electrolytes, were investigated for various polymer compositions. The mechanical strength increased, but the swelling ratio in electrolyte solution decreased with increasing PVDF–HFP content. The ion conductivity was highly affected by the type of electrolyte salt, and increased with increasing XPEG concentration. The Arrhenius‐type relationship was observed in the temperature dependence of ion conductivity. The polymer electrolyte systems prepared in this study were electrochemically stable up to about 5 V. Copyright © 2005 Society of Chemical Industry     

Preparation of monodispersed ZrO2 nanoparticles and their applications in poly[(vinylidene fluoride)‐co‐hexafluoropropylene]‐based composite polymer electrolytes

To improve the electrochemical performance of pure poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (P(VDF‐HFP))‐based gel polymer electrolytes, different amounts of monodispersed ZrO₂ nanoparticles were introduced to fabricate P(VDF‐HFP)/ZrO₂ composite polymer electrolytes (CPEs) using the phase inversion method and activated processes, in which the monodispersed ZrO₂ nanoparticles were synthesized by an easy route without any chelating agents or surfactants, and confirmed using scanning electron microscopy, particle size distribution measurement and X‐ray diffraction. The characterization results show that the as‐fabricated CPE membranes present not only an abundant porous structure, but also an improved mechanical strength. In particular, sample CPE‐5 presents the best properties when the doped content of the monodispersed ZrO₂ nanoparticles reaches 5 wt% in the polymer matrix, in which the liquid uptake and ionic conductivity at room temperature are about 192.4% and 3.926 mS cm^?1, and the electrochemical working window and thermal decomposition temperature can increase to 5.1 V and 420 °C, respectively. Moreover, an assembled LiCoO₂/CPE‐5/Li coin cell can deliver excellent rate and cycling performance, in which the discharge specific capacity of the cell can show about 83.95% capacity retention at 2.0 C after 85 cycles. © 2018 Society of Chemical Industry     

Effect of 1‐butyl‐3‐methylimidazolium iodide containing electrospun poly(vinylidene fluoride‐co‐hexafluoropropylene) membrane electrolyte on the photovoltaic performance of dye‐sensitized solar cells

Electrospun poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP) membrane was prepared from a solution of 16 wt % of PVdF‐HFP containing acetone/N,N‐dimethyl acetamide (7:3 wt %). The prepared electrospun PVdF‐HFP membrane (esPM) was then soaked in ionic liquid electrolyte containing 0.5M LiI, 0.05M I₂ , and 0.5M 4‐tert butylpyridine, 0.5M 1‐butyl‐3‐methylimidazolium iodide (BMImI) in acetonitrile to get electrospun PVdF‐HFP membrane electrolyte (esPME). The effect of various concentrations of BMImI containing esPME on ionic conductivity was studied by AC‐impedance measurements and the diffusion co‐efficients was determined by linear sweep voltammetry. The photovoltaic performance of a DSSC fabricated using 0.5M BMImI containing electrospun PVdF‐HFP membrane electrolyte (0.5M BMImI‐esPME) has power conversion efficiency (PCE) of 6.42%. But the stability of the DSSC fabricated using 0.5M BMImI‐esPME was considerably superior to that fabricated using 0.5M BMImI containing liquid electrolyte (0.5M BMImI‐LE). © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42032.     

Symmetric electric double-layer capacitor containing imidazolium ionic liquid-based solid polymer electrolyte: Effect of TiO2 and ZnO nanoparticles on electrochemical behavior

Poly(vinylidene fluoride-co-hexafluoropropene) (PVDF–HFP)-based polymer electrolytes embedded with 1-ethyl-3-methylimidazolium tetrafluoroborate ioniliquid have been synthesized to improve the ionic conductivity. Electric double-layer capacitors (EDLC) have been prepared using the synthesized polymer electrolytes. Inorganic oxide fillers (5 wt %) such as titanium dioxide (TiO₂) and zinc oxide (ZnO) nanoparticles have been added to polymer electrolytes to compare the electrochemical behavior of the fabricated EDLC. The intrinsic dielectric constant of nanoparticles contributes in ionic dissociation which enhances ionic conductivity of electrolytes and also controls the specific capacitance of the EDLC fabricated with these electrolytes. Physicochemical properties of polymer nanocomposites have been investigated using X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared analysis, which confirms decrease of crystalline phase in host polymer PVDF–HFP. The maximum voltage stability is obtained for TiO₂-based polymer electrolyte. The high specific capacitance as well as high energy density is obtained for the EDLC cell with TiO₂-based polymer electrolyte compared to EDLC with ZnO nanoparticles-based electrolyte. EDLC cells show specific capacitance of 76.4 and 44.51% of initial specific capacitance value at 2000th cycle for ZnO and TiO₂-based polymer electrolytes, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48757.     

Novel amphiphilic polymer gel electrolytes based on (PEG‐b‐GMA)‐co‐MMA

Amphiphilic conetwork–structured copolymers containing different lengths of ethylene oxide (EO) chains as ionophilic units and methyl methacrylate (MMA) chains as ionophobic units were prepared by free radical copolymerization and characterized by FTIR and thermal analysis. Polymer gel electrolytes based on the copolymers complexed with liquid lithium electrolytes (dimethyl carbonate (DMC) : diethyl carbonate (DEC) : ethylene carbonate (EC) = 1 : 1 : 1 (W/W/W), LiPF₆ 1.0M) were characterized by differential scanning calorimetry and impedance spectroscopy. A maximum ion conductivity of 4.27 × 10^?4 S/cm at 25^oC was found for the polymer electrolyte based on (PEG2000‐b‐GMA)‐co‐MMA with long EO groups. Moreover, the effect of temperature on conductivity of the amphiphilic polymer electrolytes obeys the Arrhenius equation. The good room temperature conductivity of the polymer electrolytes is proposed to relate to the enhancement in the amorphous domain of the copolymers due to their amphiphilic conetwork structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Composite polymer electrolytes based on electrospun thermoplastic polyurethane membrane and polyethylene oxide for all‐solid‐state lithium batteries

To improve the electrochemical properties and enhance the mechanical strength of solid polymer electrolytes, series of composite polymer electrolytes (CPEs) were fabricated with hybrids of thermoplastic polyurethane (TPU) electrospun membrane, polyethylene oxide (PEO), SiO₂ nanoparticles and lithium bis(trifluoromethane)sulfonamide (LiTFSI). The structure and properties of the CPEs were confirmed by SEM, XRD, DSC, TGA, electrochemical impedance spectroscopy and linear sweep voltammetry. The TPU electrospun membrane as the skeleton can improve the mechanical properties of the CPEs. In addition, SiO₂ particles can suppress the crystallization of PEO. The results show that the TPU‐electrospun‐membrane‐supported PEO electrolyte with 5 wt% SiO₂ and 20 wt% LiTFSI (TPU/PEO‐5%SiO₂‐20%Li) presents an ionic conductivity of 6.1 × 10^?4 S cm^?1 at 60 °C with a high tensile strength of 25.6 MPa. The battery using TPU/PEO‐5%SiO₂‐20%Li as solid electrolyte and LiFePO₄ as cathode shows an attractive discharge capacity of 152, 150, 121, 75, 55 and 26 mA h g^?1 at C‐rates of 0.2C, 0.5C, 1C, 2C, 3C and 5C, respectively. The discharge capacity of the cell remains 110 mA h g^?1 after 100 cycles at 1C at 60 °C (with a capacity retention of 91%). All the results indicate that this CPE can be applied to all‐solid‐state rechargeable lithium batteries. © 2018 Society of Chemical Industry     

Performances of poly(vinylidene fluoride‐co‐hexafluoropropylene) ultrafiltration membranes modified with poly(vinyl pyrrolidone)

The structure and performance of modified poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐co‐HFP) ultra‐filtration membranes prepared from casting solutions with different concentrations of poly(vinyl pyrrolidone) (PVP) were investigated in this study. Membrane properties were studied in terms of membrane compaction, pure water flux (PWF), water content (WC), membrane hydraulic resistance ( R _m), protein rejection, molecular weight cut‐off (MWCO), average pore size, and porosity. PWF, WC, and thermal stability of the blend membranes increased whereas the crystalline nature and mechanical strength of the blend membranes decreased when PVP additive concentration was increased. The contact angle (CA) decreased as the PVP concentration increased in the casting solution, which indicates that the hydro‐philicity of the surface increased upon addition of PVP. The average pore size and porosity of the PVdF‐co‐HFP membrane increased to 42.82 Å and 25.12%, respectively, when 7.5 wt% PVP was blended in the casting solution. The MWCO increased from 20 to 45 kDa with an increase in PVP concentration from 0 to 7.5 wt%. The protein separation study revealed that the rejection increased as the protein molecular weight increased. The PVdF‐co‐HFP/PVP blended membrane prepared from a 7.5 wt% PVP solution had a maximum flux recovery ratio of 74.3%, which explains its better antifouling properties as compared to the neat PVdF‐co‐HFP membrane. POLYM. ENG. SCI., 55:2482–2492, 2015. © 2015 Society of Plastics Engineers     

Preparation and performance analysis of barium titanate incorporated in corn starch‐based polymer electrolytes for electric double layer capacitor application

Polymer electrolyte membranes composing of corn starch as host polymer, lithium perchlorate (LiClO₄) as salt, and barium titanate (BaTiO₃) as composite filler are prepared using solution casting technique. Ionic conductivity is enhanced on addition of BaTiO₃ by reducing the crystallinity and increasing the amorphous phase content of the polymer electrolyte. The highest ionic conductivity of 1.28 × 10^?2 S cm^?1 is obtained for 10 wt % BaTiO₃ filler in corn starch‐LiClO₄ polymer electrolytes at 75°C. Glass transition temperature (T_g) of polymer electrolytes decreases as the amount of BaTiO₃ filler is increased, as observed in differential scanning calorimetry analysis. Scanning electron microscopy and thermogravimetric analysis are employed to characterize surface morphological and thermal properties of BaTiO₃‐based composite polymer electrolytes. The electrochemical properties of the electric double‐layer capacitor fabricating using the highest ionic conductivity polymer electrolytes is investigated using cyclic voltammetry and charge‐discharge analysis. The discharge capacitance obtained is 16.22 F g^?1. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43275.     

Lithium difluoro(oxalate)borate‐based novel nanocomposite polymer electrolytes for lithium ion batteries

BACKROUND: HF formation and poor thermal stability found in commercial lithium ion batteries comprising LiPF₆ (and other salts) have hampered the replacement of LiPF₆. Therefore, a new kind of electrolyte salt is necessary to replace the one commercially available. RESULTS: A novel lithium difluoro(oxalate)borate (LiDFOB)‐based nanocomposite polymer electrolyte has been prepared in a matrix of poly[(vinylidene fluoride)‐co‐(hexafluoropropylene)] (PVdF‐HFP). The electrolyte contains ethylene carbonate and diethyl carbonate as plasticizers and nanoparticulate Sb₂O₃ as a filler. Membranes obtained by a solution casting technique were characterized by AC impedance, thermogravimetry and tensile strength measurements and morphological studies. Membranes with 5 wt% Sb₂O₃ exhibit a room‐temperature conductivity of 0.298 mS cm^?1, and are thermally stable up to ca 130 °C. Furthermore, the nanocomposite membranes show a 125% increase in mechanical stability as compared to filler‐free membranes. The structural change from α to β phases was confirmed by Raman studies. CONCLUSION: One of the important advantages of using LiDFOB lies in its bulkier DFOB anion, which also acts as solid plasticizer, thus improving the basic requirements of the electrolyte, such as mechanical and thermal stabilities, as well ionic conductivity and with a lower filler content. The overcharge tolerance of LiDFOB salt at higher temperature is also to be noted, because of the oxalate moieties. Preliminary investigations confirmed the possibility of using Sb₂O₃ nanoparticle‐filled membranes in industry in the near future. Copyright © 2008 Society of Chemical Industry     

Isothermal phase diagrams and phase‐inversion behavior of poly(vinylidene fluoride)/solvents/additives/water systems

Isothermal ternary phase diagrams of poly(vinylidene fluoride) (PVDF)/solvents/nonsolvent systems were produced using four different solvents, N,N‐dimethylacetamide (DMAc), 1‐methyl‐2‐pyrrolidinone (NMP), N,N‐dimethylformamide (DMF), and triethyl phosphate (TEP), and using water as a nonsolvent. The effects of the additives polyvinylpyrrolidone (PVP, M_w = 10,000), ethanol, and lithium perchlorate (LiClO₄) on the phase‐inversion behavior of PVDF/DMAc/water ternary system were investigated, with additive concentrations of 2 and 6 wt %, at temperatures of 25 and 70°C, respectively. Ethanol, glycerol, and water were used to study the cloud points of 10, 15, and 20 wt % PVDF/DMAc concentrations, at solution temperatures ranging from 30 to 70°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2150–2155, 2003     

Bifunctional poly(ethylene glycol) based crosslinked network polymers as electrolytes for all‐solid‐state lithium ion batteries

Polymer electrolyte based lithium ion batteries represent a revolution in the battery community due to their intrinsic enhanced safety, and as a result polymer electrolytes have been proposed as a replacement for conventional liquid electrolytes. Herein, the preparation of a family of crosslinked network polymers as electrolytes via the ‘click‐chemistry’ technique involving thiol‐ene or thiol‐epoxy is reported. These network polymer electrolytes comprise bifunctional poly(ethylene glycol) as the lithium ion solvating polymer, pentaerythritol tetrakis (3‐mercaptopropionate) as the crosslinker and lithium bis(trifluoromethane)sulfonimide as the lithium salt. The crosslinked network polymer electrolytes obtained show low T_g, high ionic conductivity and a good lithium ion transference number (ca 0.56). In addition, the membrane demonstrated sterling mechanical robustness and high thermal stability. The advantages of the network polymer electrolytes in this study are their harmonious characteristics as solid electrolytes and the potential adaptability to improve performance by combining with inorganic fillers, ionic liquids or other materials. In addition, the simple formation of the network structures without high temperatures or light irradiation has enabled the practical large‐area fabrication and in situ fabrication on cathode electrodes. As a preliminary study, the prepared crosslinked network polymer materials were used as solid electrolytes in the elaboration of all‐solid‐state lithium metal battery prototypes with moderate charge–discharge profiles at different current densities leaving a good platform for further improvement. © 2018 Society of Chemical Industry