Nanofibrous poly(ethylene oxide)‐based structures incorporated with multi‐walled carbon nanotube and graphene oxide as all‐solid‐state electrolytes for lithium ion batteries

Nanofibrous solid polymer electrolytes were prepared using the electrospinning method. These nanofibres were constructed from poly(ethylene oxide), lithium perchlorate and ethylene carbonate, which were incorporated with multi‐walled carbon nanotube (MWCNT) and graphene oxide (GO). The morphological properties of the as‐prepared electrolytes and the interaction between the components of the composites were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. X‐ray spectra and differential scanning calorimetry indicated an increase in amorphous regions of the nanofibrous electrolytes on addition of the fillers. However, the crystalline regions were increased on incorporation of fillers into polymeric film electrolytes. The conductivity values of the nanofibrous electrolytes reached 0.048 and 0.057 mS cm^?1 when 0.35 wt% MWCNT and 0.21 wt % GO were introduced into the nanofibrous structures, respectively. The capacity and cycling stability of the nanofibrous electrolytes were improved by incorporation of MWCNT filler. Furthermore, stress and elongation modulus were improved at low MWCNT and GO filler contents. Results revealed that the nanofibrous structures could be promising candidates as solvent‐free electrolytes applicable in lithium ion batteries. © 2019 Society of Chemical Industry     

Morphology and electrochemical and mechanical properties of polyethylene‐oxide‐based nanofibrous electrolytes applicable in lithium ion batteries

We report the synthesis of all‐solid‐state polymeric electrolytes based on electrospun nanofibers. These nanofibers are composed of polyethylene oxide (PEO) as the matrix, lithium perchlorate (LiClO₄) as the lithium salt and propylene carbonate (PC) as the plasticizer. The effects of the PEO, LiClO₄ and PC ratios on the morphological, mechanical and electrochemical characteristics were investigated using the response surface method (RSM) and analysis of variance test. The prepared nanofibrous electrolytes were characterized using SEM, Fourier transform infrared, XRD and DSC analyses. Conductivity measurements and tensile tests were conducted on the prepared electrolytes. The results show that the average diameter of the nanofibers decreased on reduction of the PEO concentration and addition of PC and LiClO₄. Fourier transport infrared analysis confirmed the complexation between PEO and the additives. The highest conductivity was 0.05 mS cm^?1 at room temperature for the nanofibrous electrolyte with the lowest PEO concentration and the highest ratio of LiClO₄. The optimum nanofibrous electrolyte showed stable cycling over 30 cycles. The conductivity of a polymer film electrolyte was 29 times lower than that of the prepared nanofibrous electrolyte with similar chemical composition. Furthermore, significant fading in mechanical properties was observed on addition of the PC plasticizer. The results obtained imply that further optimization might lead to practical uses of nanofibrous electrolytes in lithium ion batteries. © 2019 Society of Chemical Industry     

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     

New solid polymer electrolytes based on PEO/PAN hybrids

Hybrid polymer dry electrolytes comprised of poly(ethylene oxide) (PEO), polyacrylonitrile (PAN), and LiClO₄ were investigated. The impedance spectroscopy showed that the effect of PAN on the ion conductivity of PEO‐based electrolytes depends on the concentration of lithium salt. When the mole ratio of lithium to oxygen is 0.062 (15%LiClO₄‐PEO), adding PAN will increase the ionic conductivity. Differential scanning calorimetry, NMR, and IR data suggested that the enhanced conductivity was due to both the decreasing of the PEO crystallinity and increasing of the degree of ionization of lithium salt. There was obviously no interaction between PAN and lithium ions, and PAN acts as a reinforcing filler, and hence contributes to the mechanical strength besides reducing the crystallinity of the polymer electrolytes. When the LiClO₄‐PEO‐PAN hybrid polymer electrolyte was heated at 200°C under N₂, PAN crosslinked partially, which further decreased the crystallinity of PEO and increased the ionic conductivity, and at the same time prevented the recrystallization of PEO upon sitting at ambient environment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1530–1540, 2006     

Electrospun poly(lithium 2‐acrylamido‐2‐methylpropanesulfonic acid) fiber‐based polymer electrolytes for lithium‐ion batteries

Novel single‐ion conducting polymer electrolytes based on electrospun poly(lithium 2‐acrylamido‐2‐methylpropanesulfonic acid) (PAMPSLi) membranes were prepared for lithium‐ion batteries. The preparation started with the synthesis of polymeric lithium salt PAMPSLi by free‐radical polymerization of 2‐acrylamido‐2‐methylpropanesulfonic acid, followed by ion‐exchange of H⁺ with Li⁺. Then, the electrospun PAMPSLi membranes were prepared by electrospinning technology, and the resultant PAMPSLi fiber‐based polymer electrolytes were fabricated by immersing the electrospun membranes into a plasticizer composed of ethylene carbonate and dimethyl carbonate. PAMPSLi exhibited high thermal stability and its decomposition did not occur until 304°C. The specific surface area of the electrospun PAMPSLi membranes was raised from 9.9 m²/g to 19.5 m²/g by varying the solvent composition of polymer solutions. The ionic conductivity of the resultant PAMPSLi fiber‐based polymer electrolytes at 20°C increased from 0.815 × 10^?5 S/cm to 2.12 × 10^?5 S/cm with the increase of the specific surface area. The polymer electrolytes exhibited good dimensional stability and electrochemical stability up to 4.4 V vs. Li⁺/Li. These results show that the PAMPSLi fiber‐based polymer electrolytes are promising materials for lithium‐ion batteries. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Poly(ethylene oxide)‐based block copolymer electrolytes for lithium metal batteries

Nanostructured block copolymer electrolytes (BCEs) based on poly(ethylene oxide) (PEO) are considered as promising candidates for solid‐state electrolytes in high energy density lithium metal batteries (LMBs). Because of their self‐assembly properties, they confer on electrolytes both high mechanical strength and sufficient ionic conductivity, which linear PEO cannot provide. Two types of PEO‐based BCEs are commonly known. There are the traditional ones, also called dual‐ion conducting BCEs, which are a mixture of block copolymer chains and lithium salts. In these systems, the cations and anions participate in the conduction, inducing a concentration polarization in the electrolyte, thus leading to poor performances of LMBs. The second family of BCEs are single‐lithium‐ion conducting BCEs (SIC‐BCEs), which consist of anions being covalently grafted to the polymer backbone, therefore involving conduction by lithium ions only. SIC‐BCEs have marked advantages over dual‐ion conducting BCEs due to a high lithium ion transference number, absence of anion concentration gradients as well as low rate of lithium dendrite growth. This review focuses on the recent developments in BCEs for applications in LMBs with particular emphasis on the physicochemical and electrochemical properties of these materials. © 2018 Society of Chemical Industry     

Influence of Barium Titanate on poly(vinyl pyrrolidone)‐based composite polymer blend electrolytes for lithium battery applications

Nanocomposite polymer blend electrolytes based on poly (ethylene oxide), poly (vinyl pyrrolidone) that contained lithium perchlorate as a dopant, propylene carbonate (PC) as a plasticizer and Barium Titanate (BaTiO₃) as a filler were prepared for various concentrations of BaTiO₃ using solvent casting technique. The structural and complex formations of the composite electrolyte membranes were confirmed by X‐ray diffraction and FTIR analysis. The addition of BaTiO₃ nanofillers improved the ionic conductivity of the polymer electrolytes to some extent when the content of the BaTiO₃ is 10 wt%. The addition of BaTiO₃ also enhanced the thermal stability of the electrolyte. The surface morphology of the sample having a maximum ionic conductivity was studied by AFM. Molecular motion in the polymeric media was supported by fluorescence studies. The charge transfer arises between the polymer blend and Li‐ions were confirmed by UV‐Vis analysis. POLYM. COMPOS., 36:302–311, 2015. © 2014 Society of Plastics Engineers     

Synthesis and characterization of SrBi4Ti4O15ferroelectric filler based composite polymer electrolytes for lithium ion batteries

Composite polymer electrolytes (CPEs) based on poly (ethylene oxide) (PEO) (Mol.Wt ∼6×10⁵) complexed with LiN(CF₃SO₂)₂ lithium salt and SrBi₄Ti₄O₁₅ ferroelectric ceramic filler have been prepared as films. Citrate gel technique and conventional solid state technique were employed for the synthesis of the ferroelectric fillers in order to study the effect of particle size of the filler on ionic conductivity of the polymer electrolyte. Characterization techniques such as X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM) and temperature dependant DC conductivity studies were taken for the prepared polymer composite electrolytes. The broadening of DTA endotherms on addition of ceramic fillers to the polymer salt complex indicated the reduction in crystallinity. An enhancement in conductivity was observed with the addition of SrBi₄Ti₄O₁₅ as filler to the (PEO)₈-LiN(CF₃SO₂)₂ polymer salt complexes. Among the investigated samples (PEO)₈-LiN(CF₃SO₂)₂ +10 wt% SrBi₄Ti₄O₁₅ (citrate gel) polymer composite exhibits a maximum conductivity.     

Structural and dielectric studies of amorphous and semicrystalline polymers blend‐based nanocomposite electrolytes

The solid polymeric nanocomposite electrolyte (SPNE) films based on the blend of amorphous poly(methyl methacrylate) (PMMA) and semicrystalline poly(ethylene oxide) (PEO) (PMMA:PEO = 80:20 wt %) doped with lithium perchlorate (LiClO₄) salt and montmorillonite (MMT) clay nanofiller were prepared by classical solution cast, ultrasonic assisted solution cast and ultrasonication along with microwave irradiated solution cast followed by melt‐pressing methods. The X‐ray diffraction study of these electrolytes revealed the amorphous behavior with intercalated MMT structures. The suppressed crystallinity of PEO in the blend electrolyte complexes confirmed the existence of single discrete PEO chains confined within the PMMA domains. The dielectric relaxation spectroscopy of these materials was performed over the frequency range 20 Hz to 1 MHz, at ambient temperature. The presence of a singular relaxation peak in the loss tangent and electric modulus spectra of these electrolytes confirms a coupled cooperative chain segmental dynamics of the blend polymer owing to their miscible amorphous morphology. The behavior of transient complexes formed between the polymers functional groups, lithium cations and the intercalated MMT nanoplatelets was explored. The ambient temperature ionic conductivity of these electrolytes depends on the structural dynamics and the sample preparation methods. It is revealed that the presence of PEO in the PMMA matrix mainly governs the structural, dielectric, and ionic properties of these SPNE films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41311.     

Effect of surface modified porous inorganic-organic hybrid polyphosphazene nanotubes on the properties of polyethylene oxide based solid polymer electrolytes

2-(2-methyloxyethoxy)ethanol modified poly (cyclotriphosphazene-co-4,4′-sufonyldiphenol) (PZS) nanotubes were synthesized and solid composite polymer electrolytes based on the surface modified polyphosphazene nanotubes added to PEO/LiClO₄ model system were prepared. Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) were used to investigate the characteristics of the composite polymer electrolytes (CPE). The ionic conductivity, lithium ion transference number and electrochemical stability window can be enhanced after the addition of surface modified PZS nanotubes. The electrochemical investigation shows that the solid composite polymer electrolytes incorporated with PZS nanotubes have higher ionic conductivity and lithium ion transference number than the filler SiO₂. Maximum ionic conductivity values of 4.95 × 10⁻⁵ S cm⁻¹ at ambient temperature and 1.64 × 10⁻³ S cm⁻¹ at 80 °C with 10 wt % content of surface modified PZS nanotubes were obtained and the lithium ion transference number was 0.41. The good chemical properties of the solid state composite polymer electrolytes suggested that the inorganic-organic hybrid polyphosphazene nanotubes had a promising use as fillers in solid composite polymer electrolytes and the PEO₁₀-LiClO₄-PZS nanotubes solid composite polymer electrolyte can be used as a candidate material for lithium polymer batteries.     

Composite polymer electrolyte based on (PEO)6:NaPO3 dispersed with BaTiO3

BACKGROUND: Polymer electrolytes have attracted considerable attention as regards portable solid‐state electrochemical device applications. The present investigation is focused on the characterization of a new Na⁺ ion conducting polymer electrolyte (PEO)₆:NaPO₃ dispersed with 3–10 wt% BaTiO₃ (0.7 µm) fillers. The composite polymer electrolytes (CPEs) were prepared by a solution‐casting method and characterized using various physical measurement techniques. RESULTS: Differential scanning calorimetry results indicate a maximum reduction in the degree of crystallinity of the polymer from 62.6% for uncomplexed poly(ethylene oxide) (PEO) to 27.6% for the CPE with 6 wt% BaTiO₃. This substantiates an enhancement in the amorphous phase of the polymer inferred from X‐ray diffraction and optical micrographs. The CPE dispersed with 6 wt% BaTiO₃ is found to be the best composition exhibiting a maximum ionic conductivity of 1.2 × 10^?6 S cm^?1 at 345 K with cationic transport number (t) of 0.33. CONCLUSIONS: An enhancement in the ionic conductivity of about two orders of magnitude is achieved for the composite electrolytes when compared to filler‐free solid polymer electrolyte. Correlation of the temperature‐dependent conductivity, activation energy for ion migration and transport number enables an understanding of the role played by the fillers in conduction characteristics of the CPEs. Copyright © 2007 Society of Chemical Industry     

Studies of solvent effect on the conductivity of 2‐mercaptopyridine‐doped solid polymer blend electrolytes and its application in dye‐sensitized solar cells

Solvents and electrolytes play an important role in the fabrication of dye‐sensitized solar cells (DSSCs). We have studied the poly(ethylene oxide)‐poly(methyl methacrylate)‐KI‐I₂ (PEO‐PMMA‐KI‐I₂) polymer blend electrolytes prepared with different wt % of the 2‐mercaptopyridine by solution casting method. The polymer electrolyte films were characterized by the FTIR, X‐ray diffraction, electrochemical impedance and dielectric studies. FTIR spectra revealed complex formation between the PEO‐PMMA‐KI‐I₂ and 2‐mercaptopyrindine. Ionic conductivity data revealed that 30% 2‐mercaptopyridine‐doped PEO‐PMMA‐KI‐I₂ electrolyte can show higher conductivity (1.55 × 10^?5 S cm^?1) than the other compositions (20, 40, and 50%). The effect of solvent on the conductivity and dielectric of solid polymer electrolytes was studied for the best composition (30% 2‐mercaptopyridine‐doped PEO‐PMMA‐KI‐I₂) electrolyte using various organic solvents such as acetonitrile, N,N‐dimethylformamide, 2‐butanone, chlorobenzene, dimethylsulfoxide, and isopropanol. We found that ac‐conductivity and dielectric constant are higher for the polymer electrolytes processed from N,N‐dimethylformamide. This observation revealed that the conductivity of the solid polymer electrolytes is dependent on the solvent used for processing and the dielectric constant of the film. The photo‐conversion efficiency of dye‐sensitized solar cells fabricated using the optimized polymer electrolytes was 3.0% under an illumination of 100 mW cm^?2. The study suggests that N,N‐dimethylformamide is a good solvent for the polymer electrolyte processing due to higher ac‐conductivity beneficial for the electrochemical device applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42489.     

Characterization of PEO-PAN hybrid solid polymer electrolytes

Hybrid solid polymer electrolytes (HSPE) of high ionic conductivity were prepared using polyethylene oxide (PEO), polyacrylonitrile (PAN), propylene carbonate (PrC), ethylene carbonate (EC), and LiClO₄. These electrolyte films were dry, free standing, and dimensionally stable. The HSPE films were characterized by constructing symmetrical cells containing nonblocking lithium electrodes as well as blocking stainless steel electrodes. Studies were made on ionic conductivity, electrochemical reaction, interfacial stability, and morphology of the films using alternating current impedance spectroscopy, infrared spectroscopy, and scanning electron microscopy. The properties of HSPE were compared with the films prepared using (i) PEO, PrC, and LiClO₄; and (ii) PAN, PrC, EC, and LiClO₄. The specific conductivity of the HSPE films was marginally less. Nevertheless, the dimensional stability was much superior. The interfacial stability of lithium was similar in the three electrolyte films. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2191–2199, 1997     

Morphology,crystallinity, and electrochemical properties of in situ formed poly(ethylene oxide)/TiO2 nanocomposite polymer electrolytes

A method to produce nanocomposite polymer electrolytes consisting of poly(ethylene oxide) (PEO) as the polymer matrix, lithium tetrafluoroborate (LiBF₄) as the lithium salt, and TiO₂ as the inert ceramic filler is described. The ceramic filler, TiO₂, was synthesized in situ by a sol–gel process. The morphology and crystallinity of the nanocomposite polymer electrolytes were examined by scanning electron microscopy and differential scanning calorimetry, respectively. The electrochemical properties of interest to battery applications, such as ionic conductivity, Li⁺ transference number, and stability window were investigated. The room‐temperature ionic conductivity of these polymer electrolytes was an order of magnitude higher than that of the TiO₂ free sample. A high Li⁺ transference number of 0.51 was recorded, and the nanocomposite electrolyte was found to be electrochemically stable up to 4.5 V versus Li⁺/Li. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2815–2822, 2003     

Preparation and physicochemical performances of poly[(vinylidene fluoride)‐co‐hexafluoropropylene]‐based composite polymer electrolytes doped with modified carbon nanotubes

Modified carbon nanotubes (m‐CNTs) were successfully prepared by the interactions between nitric and sulfuric acids and CNTs, which was confirmed using Fourier transform infrared spectroscopy. Poly[(vinylidene fluoride)‐co‐hexafluoropropylene]‐based composite polymer electrolyte (CPE) membranes doped with various amounts of m‐CNTs were prepared by phase inversion method. The desired CPEs were obtained by soaking the liquid electrolytes for 30 min. The physicochemical and electrochemical properties of the CPE membranes were investigated using scanning electron microscopy, X‐ray diffraction, thermogravimetry, electrochemical impedance spectroscopy and linear sweep voltammetry. The results show that the CPE membranes doped with 2.2 wt% m‐CNTs possess the smoothest surface and the highest decomposition temperature about 450 °C. Obviously, adding an appropriate amount of m‐CNTs into the polymer matrix can decrease the crystallinity and enhance the ionic conductivity; the temperature dependence of ionic conductivity follows the Arrhenius relation and the ionic conductivity at room temperature is up to 4.9 mS cm^?1. The interfacial resistance can reach a stable value of about 415 Ω cm^?2 after 10 days storage. The excellent rate and cycle performances with an electrochemical working window up to 5.4 V ensure that the CPEs doped with 2.2 wt% m‐CNTs can be considered as potential candidates as polymer electrolyte for lithium ion batteries. © 2013 Society of Chemical Industry     

New type of lithium poly(polyfluoroalkoxy)sulfonylimides as salts for PEO‐based solvent‐free electrolytes

A new type of lithium salts, —SO₂NLiSO₂OCH₂(CF₂)_nCH₂O_m— (LiPPFASI, where n = 2, 3, 4, 6, and 7), was used as salts in poly(ethylene oxide) (PEO)‐based solvent‐free electrolytes. The conductivity and electrochemical stability behaviors were studied. The results showed the electrolytes almost have a similar conductivity and the PEO–LiPPFASI (n = 3, EO/Li = 10) was the relatively better system under the experiment conditions. Moreover, most systems were found to be oxidatively stable up to 5.5 V versus Li/Li⁺ and the lithium deposition‐stripping process on the electrode was reversible for all the polymer electrolytes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1882–1885, 2001     

全固态锂离子电池的研究进展与挑战

全固态锂离子电池具有安全性高、电化学性能优异等优点,但存在电极与电解质界面相容性差、室温离子电导率低等问题。本文总结了以上问题产生的原因及解决方案。对于正极界面,可复合正极材料与固态电解质、构造三维多孔结构固态电解质或在界面处引入缓冲层。对于负极界面,可设计界面层、原位聚合生成固态电解质、构造固态电解质骨架或使用自愈合和弹性固态电解质。对于固态电解质自身,以聚氧化乙烯（PEO）固态聚合物电解质为例,可添加增塑剂、无机陶瓷填料或构造聚合物共混物与嵌段共聚物。最后,对今后的研究方向提出了建议：应注重优化电极/固态电解质界面层;探索锂离子传输机理;构建具有高离子电导率的固态电解质等。     

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     

Fabrication and characterization of PEO/PPC polymer electrolyte for lithium‐ion battery

A new poly(propylene carbonate)/poly(ethylene oxide) (PEO/PPC) polymer electrolytes (PEs) have been developed by solution‐casting technique using biodegradable PPC and PEO. The morphology, structure, and thermal properties of the PEO/PPC polymer electrolytes were investigated by scanning electron microscopy, X‐ray diffraction, and differential scanning calorimetry methods. The ionic conductivity and the electrochemical stability window of the PEO/PPC polymer electrolytes were also measured. The results showed that the T_g and the crystallinity of PEO decrease, and consequently, the ionic conductivity increases because of the addition of amorphous PPC. The PEO/50%PPC/10%LiClO₄ polymer electrolyte possesses good properties such as 6.83 × 10^?5 S cm^?1 of ionic conductivity at room temperature and 4.5 V of the electrochemical stability window. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation and ionic conductive properties of all‐solid polymer electrolytes based on multiarm star block polymers

A series of star block polymers with a hyperbranched core and 26 arms are successfully synthesized by atom transfer radical polymerization of styrene (St), and poly(ethylene glycol) methyl ether methacrylate from a hyperbranched polystyrene (HBPS) multifunctional initiator. All‐solid polymer electrolytes composed of these multiarm star polymers and lithium salts are prepared. The influences of polyoxyethylene (PEO) side‐chain length, PEO content, lithium salt concentration and type, and the structure of polymer on ionic conductivity are systematically investigated. The resulting polymer electrolyte with the longest PEO side chains exhibits the best ionic conductive properties. The maximum conductivity is 0.8 × 10^?4 S cm^?1 at 25°C with EO/Li = 30. All the prepared multiarm star block polymers possess good thermal stability. The mechanical property is greatly improved owing to the existence of polystyrene blocks in the multiarm star polymer molecules, and flexible films can be obtained by solution‐casting technique. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013