Publications by authors named "Adrien Lignie"

3 Publications

  • Page 1 of 1

Electropolymerized Star-Shaped Benzotrithiophenes Yield π-Conjugated Hierarchical Networks with High Areal Capacitance.

ACS Appl Mater Interfaces 2016 05 4;8(19):12091-100. Epub 2016 May 4.

Physical Sciences & Engineering Division , King Abdullah University of Science & Technology (KAUST) , Thuwal 23955-6900, Saudi Arabia.

Unlabelled: High-surface-area π-conjugated polymeric networks have the potential to lend outstanding capacitance to supercapacitors because of the pronounced faradaic processes that take place across the dense intimate interface between active material and electrolytes. In this report, we describe how benzo[1,2-b:3,4-b':5,6-b″]trithiophene (BTT) and tris(ethylenedioxythiophene)benzo[1,2-b:3,4-b':5,6-b″]trithiophene (TEBTT) can serve as 2D (trivalent) building blocks in the development of electropolymerized hierarchical π-conjugated frameworks with particularly high areal capacitance. In comparing electropolymerized networks of BTT, TEBTT, and their copolymers with EDOT, we show that TEBTT/EDOT-based copolymers, i.e., P(TEBTT/EDOT), can achieve higher areal capacitance (e.g., as high as 443.8 mF cm(-2) at 1 mA cm(-2)) than those achieved by their respective homopolymers (PTEBTT and PEDOT) in the same experimental conditions of electrodeposition (PTEBTT: 271.1 mF cm(-2) (at 1 mA cm(-2)) and

Pedot: 12.1 mF cm(-2) (at 1 mA cm(-2))). For example, P(TEBTT/EDOT)-based frameworks synthesized in a 1:1 monomer-to-comonomer ratio show a ca. 35× capacitance improvement over PEDOT. The high areal capacitance measured for P(TEBTT/EDOT)-based frameworks can be explained by the open, highly porous hierarchical morphologies formed during the electropolymerization step. With >70% capacitance retention over 1000 cycles (up to 89% achieved), both PTEBTT- and P(TEBTT/EDOT)-based frameworks are resilient to repeated electrochemical cycling and can be considered promising systems for high life cycle capacitive electrode applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.5b09962DOI Listing
May 2016

High-temperature elastic moduli of flux-grown α-GeO2 single crystal.

Chemphyschem 2014 Jan 2;15(1):118-25. Epub 2013 Dec 2.

Institut Charles Gerhardt Montpellier, UMR 5253, CNRS-UM2-ENSCM-UM1, C2M, Université Montpellier 2, CC 1504, Place Eugène Bataillon, 34095 Montpellier Cédex 5 (France), Fax: (+33) 467144290.

From high-precision Brillouin spectroscopy measurements, six elastic constants (C11, C33, C44, C66, C12, and C14) of a flux-grown GeO2 single crystal with the α-quartz-like structure are obtained in the 298-1273 K temperature range. High-temperature powder X-ray diffraction data is collected to determine the temperature dependence of the lattice parameters and the volume thermal expansion coefficients. The temperature dependence of the mass density, ρ, is evaluated and used to estimate the thermal dependence of its refractive indices (ordinary and extraordinary), according to the Lorentz-Lorenz equation. The extraction of the ambient piezoelectric stress contribution, e11, from the C'11-C11 difference gives, for the piezoelectric strain coefficient d11 , a value of 5.7(2) pC N(-1), which is more than twice that of α-quartz. As the quartz structure of α-GeO2 remains stable until melting, piezoelectric activity is observed until 1273 K.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cphc.201300793DOI Listing
January 2014

Vibrational origin of the thermal stability in the highly distorted α-quartz-type material GeO2: an experimental and theoretical study.

Inorg Chem 2013 Jun 4;52(12):7271-9. Epub 2013 Jun 4.

Institut Charles Gerhardt Montpellier (ICGM), UMR 5253 CNRS-UM2-ENSCM-UM1, équipe C2M, Université Montpellier II, Place Eugène Bataillon, 34095 Montpellier cedex 5, France.

We report an experimental and theoretical vibrational study of the high-performance piezoelectric GeO2 material. Polarized and variable-temperature Raman spectroscopic measurements on high-quality, water-free, flux-grown α-quartz GeO2 single crystals combined with state-of-the-art first-principles calculations allow the controversies on the mode symmetry assignment to be solved, the nature of the vibrations to be described in detail, and the origin of the high thermal stability of this material to be explained. The low-degree of dynamic disorder at high-temperature, which makes α-GeO2 one of the most promising piezoelectric materials for extreme temperature applications, is found to originate from the absence of a libration mode of the GeO4 tetrahedra.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ic4009416DOI Listing
June 2013