Abstract. This paper deals with the synthesis and characterization of a new type of anhydrous ionic conducting lithium doped membranes consist of polyimide (PI), poly (ethylene oxide) (PEO) and lithium trifluoromethanesulfonate (LiCF 3 SO 3 ) for solid polymer electrolyte (SPE). For this purpose, different molar ratios of lithium salt (Li-salt) solution are added into poly (amic acid) (PAA) intermediate prepared from the reaction of 3,3!,4,4!-benzophenon tetracarboxylic dianhydride (BTDA) and 4,4!-oxydianiline (ODA). PEO is incorporated into PAA since it forms more stable complexes and possess high ionic conductivities. Then, Li-salt containing PAA solutions are imidized by thermal process. The effect of interaction between host polymer and Li-salt is characterized by FT-IR (Fourier Transform Infrared) spectroscopy and SEM (scanning electron micrsocopy). The conductivities of Li-salt and PEO containing PI composite membranes are in the range of 10 -7 -10 -5 S·cm -1 . The conductivity increases with incorporation of PEO. Thermogravimetric analysis results reveal that the PI/PEO/LiCF 3 SO 3 composite polymer electrolyte membranes are thermally stable up to 500°C.

UV-cured caprolactone-based polyurethane acrylate (PUA) polymer blend electrolytes were prepared and characterised. To develop polymer electrolytes suited to ambient temperature, an ionically-conductive and reliable polymer electrolyte based on urethane acrylate resins synthesised from a fluorine-containing di-functional oligomer 6F ethoxylated diacrylate, a di-functional reactive diluent 1,6-hexanediol diacrylate for adjusting the viscosity, and a radical photo-initiator doped with a mixture of lithium salts were used. Free-standing flexible electrolyte films were prepared by UV-curing via free-radical photopolymerisation. The performance of the lithium polymer cell system (Li/PE(F4)/LiCoO2) was determined by electrochemical impedance spectroscopy, cyclic voltammetry, a galvanostatic recurrent differential pulse, chronocoulometry and chronoamperometry. The electrolyte with optimal amounts of fluorine-containing oligomer and optimal salt mixture content exhibited enhanced conductivity, showing a conductivity of 1.00 × 10 −4 S cm −1 at ambient temperature. The specific capacity, specific energy and specific power of a Li/PE(F4)/LiCoO2 cell were also determined.

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In this work, we described the synthesis of organic–inorganic hybrid gel electrolytes combining electrospinning, sol–gel, and ultraviolet (UV) curing techniques in order to investigate their ionic conductivity properties. First, 3‐glycidyloxypropyl trimethoxysilane modified polyamic acid and alkoxysilane functional poly(dimethyl siloxane) were electrospun together. Then, the following thermal imidization, the obtained fiber was cured in the UV curable gel formulation. To improve the interaction between fiber and gel matrix, 3‐(trimethoxysilyl)propyl methacrylate was partly hydrolyzed and then used as a bifunctional crosslinker. Finally, the membrane was soaked into 0.5 M LiFP6 salt solution to obtain organic–inorganic hybrid gel electrolytes. The chemical structure, ionic conductivity, and range of electrochemical stability window of the photocured nanocomposite electrolytes were investigated by using FTIR, thermogravimetric analysis, differential scanning calorimetry, electrochemical impedance spectroscopy, linear sweep voltammetry, and SEM analysis. The acquired results from experiments indicate that a convenient nanocomposite electrolyte for lithium‐ion batteries with high electrolyte (Li salt) uptake, adequate conductivity (1.02 × 10−3 S cm−1) at ambient temperature and electrochemically stable between 1 and 6 V had been prepared. POLYM. ENG. SCI., 60:619–629, 2020. © 2019 Society of Plastics Engineers

In this study, a novel ion conductive polyimide (PI) nanofiber reinforced photocured hybrid electrolyte has been fabricated. Polyimide fibers were fabricated with the reaction between 4,4′‐oxydianiline (ODA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) followed by electrospinning and thermal imidization methods. Then, PI electrospun fibers were dipped into hybrid resin formulation containing bisphenol A ethoxylate dimethacrylate (BEMA), poly (ethylene glycol) methyl ether methacrylate (PEGMA) and 3‐(methacryloyloxy) propyltrimethoxysilane (MEMO) and then photocured to prepare PI nanofiber reinforced electrolyte membrane. Photocured membranes were soaked into lithium hexafluorophosphate (LiPF6) before measuring electrochemical stability and ionic conductivity of hybrid polyelectrolyte. The chemical structure and electrochemical performance of the electrolytes were examined by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and scanning electron microscopy (SEM) analysis. The incorporation of MEMO into organic matrix effectively increased the modulus from 2.83 to 5.91 MPa. The obtained results showed that a suitable electrolyte for Li‐ion batteries with high lithium uptake ratio, high conductivity (7.2 × 10−3 S cm−1) at ambient temperature and wide stability window above 5.5 V had been prepared. Copyright © 2017 John Wiley & Sons, Ltd.