Yu-Chi Pan

A new highly conductive organic-inorganic solid polymer electrolyte based on a di-ureasil matrix doped with lithium perchlorate

A new hybrid organic-inorganic polymer electrolyte based on poly(propylene glycol) tolylene 2,4-diisocyanate terminated (PPGTDI), poly(propylene glycol)-block–poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) (ED2000) and 3-isocyanatepropyltriethoxysilane (ICPTES) has been synthesized and characterized. A maximum ionic conductivity value of 1.0 × 10−4 S cm−1 at 30 °C and 1.1 × 10−3 S cm−1 at 80 °C is achieved for the hybrid electrolyte with a [O]/[Li] ratio of 32. The conductivity mechanism changes from Arrhenius to Vogel-Tamman-Fulcher (VTF) behavior with the increase in temperature from 20 to 80 °C. The present hybrid electrolyte system offers a remarkable improvement in ionic conductivity by at least one order of magnitude higher than the previously reported organic-inorganic electrolytes. The 7Li NMR (nuclear magnetic resonance) results reveal that there exists a strong correlation between the dynamic properties of the charge carriers and the polymer matrix. Two Li+ local environments are identified, for the first time, in such a di-ureasil based polymer electrolyte. The electrochemical stability window is found to be in the range of 4.6–5.0 V, which ensures that the present hybrid electrolyte is a potential polymer electrolyte for solid-state rechargeable lithium ion batteries.

Synthesis and characterization of a highly conductive organic–inorganic hybrid polymer electrolyte based on amine terminated triblock polyethers and its application in electrochromic devices

A new highly ion conductive organic–inorganic hybrid electrolyte based on the reaction of triblock co-polymer poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) (ED2003) with 3-(glycidyloxypropyl)trimethoxysilane (GLYMO) and followed by co-condensation with 2-methoxy(polyethyleneoxy)propyl trimethoxysilane (MPEOPS) in the presence of LiClO4 was synthesized by a sol–gel process and characterized by a variety of experimental techniques. The maximum ionic conductivities of 1.1 × 10−4 S cm−1 at 30 °C and 6.0 × 10−4 S cm−1 at 80 °C were obtained for the hybrid electrolyte with a [O]/[Li] ratio of 24. The conductivity mechanism changed from Arrhenius at lower temperatures to Vogel–Tamman–Fulcher (VTF) behavior at higher temperatures. The results of solid-state NMR confirmed the structural framework of the hybrids, and provided a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains. The electrochemical stability window was found to be around 3.7–4.5 V, which is sufficient for electrochemical device applications. Preliminary tests performed with prototype electrochromic devices (ECDs) comprising the hybrid electrolyte with various [O]/[Li] ratios and mesoporous WO3 as the cathode layer are extremely encouraging. The best performance device exhibits an optical density change of 0.58, coloration efficiency of 375 cm2 C−1 and a good cycle life with the hybrid electrolyte with a [O]/[Li] ratio of 24. The present hybrid electrolyte offers a remarkable ionic conductivity and coloration efficiency in the solid state than previously reported organic–inorganic hybrid electrolytes.

Synthesis, Multinuclear NMR Characterization and Dynamic Property of Organic-Inorganic Hybrid Electrolyte Membrane Based on Alkoxysilane and Poly(oxyalkylene) Diamine

Organic–inorganic hybrid electrolyte membranes based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) bis(2-aminopropyl ether) complexed with LiClO4 via the co-condensation of tetraethoxysilane (TEOS) and 3-(triethoxysilyl)propyl isocyanate have been prepared and characterized. A variety of techniques such as differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, alternating current (AC) impedance and solid-state nuclear magnetic resonance (NMR) spectroscopy are performed to elucidate the relationship between the structural and dynamic properties of the hybrid electrolyte and the ion mobility. A VTF (Vogel-Tamman-Fulcher)-like temperature dependence of ionic conductivity is observed for all the compositions studied, implying that the diffusion of charge carriers is assisted by the segmental motions of the polymer chains. A maximum ionic conductivity value of 5.3 × 10−5 Scm−1 is obtained at 30 °C. Solid-state NMR results provide a microscopic view of the effects of salt concentrations on the dynamic behavior of the polymer chains.

Synthesis and solid-state NMR characterization of cubic mesoporous silica SBA-1 functionalized with sulfonic acid groups

Well-ordered cubic mesoporous silicas SBA-1 functionalized with sulfonic acid groups have been synthesized through in situ oxidation of mercaptopropyl groups with H(2)O(2) via co-condensation of tetraethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) templated by cetyltriethylammonium bromide (CTEABr) under strong acidic conditions. Various synthesis parameters such as the amounts of H(2)O(2) and MPTMS on the structural ordering of the resultant materials were systematically investigated. The materials thus obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), multinuclear solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, (29)Si{(1)H} 2D HETCOR (heteronuclear correlation) NMR spectroscopy, thermogravimetric analysis (TGA), and nitrogen sorption measurements. By using (13)C CPMAS NMR technique, the status of the incorporated thiol groups and their transformation to sulfonic acid groups can be monitored and, as an extension, to define the optimum conditions to be used for the oxidation reaction to be quantitative. In particular, (29)Si{(1)H} 2D HETCOR NMR revealed that the protons in sulfonic acid groups are in close proximity to the silanol Q(3) species, but not close enough to form a hydrogen bond.

A new organic–inorganic hybrid electrolyte based on polyacrylonitrile, polyether diamine and alkoxysilanes for lithium ion batteries: synthesis, structural properties, and electrochemical characterization

A new type of organic–inorganic hybrid polymer electrolyte based on poly(propylene glycol)-block-poly(ethylene glycol)-block-poly-(propylene glycol)bis(2-aminopropyl ether), polyacrylonitrile (PAN), 3-(glycidyloxypropyl)trimethoxysilane (GLYMO) and 3-(aminopropyl)trimethoxysilane (APTMS) complexed with LiClO4 via the co-condensation of organosilicas was synthesized. The structural and electrochemical properties of the materials were systematically investigated by a variety of techniques including differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), multinuclear (13C, 29Si, 7Li) solid-state NMR, AC impedance, linear sweep voltammetry (LSV) and charge–discharge measurement. A maximum ionic conductivity value of 7.4 × 10−5 S cm−1 at 30 °C and 4.6 × 10−4 S cm−1 at 80 °C is achieved for the solid hybrid electrolyte. The 7Li NMR measurements reveal the strong correlation of the lithium cation and the polymer matrix, and the presence of two lithium local environments. After swelling in an electrolyte solvent, the plasticized hybrid membrane exhibited a maximum ionic conductivity of 6.4 × 10−3 S cm−1 at 30 °C. The good value of the electrochemical stability window (∼4.5 V) makes the plasticized hybrid electrolyte membrane promising for electrochemical device applications. The preliminary lithium ion battery testing shows an initial discharge capacity value of 123 mA h g−1 and a good cycling performance with the plasticized hybrid electrolyte.

Rapid sonochemical synthesis of MCM-41 type benzene-bridged periodic mesoporous organosilicas

Benzene-bridged periodic mesoporous organosilicas (PMOs) with the MCM-41 were synthesized by a rapid sonochemical process via co-condensation of tetraethoxysilane (TEOS) and 1,4-bis(triethoxysilyl) benzene (BTEB) under basic conditions within a few minutes using cetyltrimethylammoniumbromide (CTMABr) as a structure-directing agent. The molar ratio of the silicon precursors and the synthesis time were varied in order to investigate their influence on the structural ordering of the materials. The characteristics of the materials were evaluated by X-ray diffraction (XRD), N2-sorption, transmission electron microscopy (TEM) and solid-state NMR spectroscopy. The resultant materials exhibited well-ordered hexagonal mesostructures with surface areas in the range of 602-1237 m(2)/g, pore volumes of 0.37-0.68 cm(3)/g, and pore diameters in the range of 2.5-3.5 nm. Two dimensional (29)Si{(1)H} heteronuclear correlation (HETCOR) NMR spectra confirmed the formation of a single mesophase with various Q (from TEOS) and T (from BTEB) silicon species located randomly within the pore walls due to the co-condensation of BTEB and TEOS, which excluded the possibility of formation of island or two separate phases within such a short synthesis time. The prime advantage of the present synthesis route is that it can effectively reduce the total synthesis time from days to a few minutes, much shorter than the conventional benzene-bridged PMOs synthesis methods.

A one-pot organic–inorganic co-assembling route to ordered mesoporous carbons with cubic and bimodal pore structures

Highly ordered cubic mesoporous carbons with the cubic I4132 mesostructure have been synthesized via organic–inorganic self-assembly of tetraethoxysilane (TEOS), triblock copolymer Pluronic P123, and sucrose under acidic conditions.