Review of the proton exchange membranes for fuel cell applications

The state-of-the-art of polymer electrolyte membrane fuel cell (PEMFC) technology is based on perfluorosulfonic acid (PFSA) polymer membranes operating at a typical temperature of 80 °C. Some of the key issues and shortcomings of the PFSA-based PEMFC technology are briefly discussed. These include water management, CO poisoning, hydrogen, reformate and methanol as fuels, cooling, and heat recovery. As a means to solve these shortcomings, high-temperature polymer electrolyte membranes for operation above 100 °C are under active development. This treatise is devoted to a review of the area encompassing modified PFSA membranes, alternative sulfonated polymer and their composite membranes, and acid−base complex membranes. PFSA membranes have been modified by swelling with nonvolatile solvents and preparing composites with hydrophilic oxides and solid proton conductors. DMFC and H2/O2(air) cells based on modified PFSA membranes have been successfully operated at temperatures up to 120 °C under ambient pressure...

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Approaches and Recent Development of Polymer Electrolyte Membranes for Fuel Cells Operating above 100 °C

Electrochromic tungsten oxide films: Review of progress 1993–1998

https://www.fkit.unizg.hr/_download/repository/Smart_Windows-_Review.pdf

Properties, requirements and possibilities of smart windows for dynamic daylight and solar energy control in buildings: A state-of-the-art review

https://hal.archives-ouvertes.fr/hal-00120432/document

Raman Spectroscopy of Nanomaterials: How Spectra Relate to Disorder, Particle Size and Mechanical Properties

Proton-conducting sol-gel hybrids containing heteropoly acids

Hybrid organic−inorganic proton conducting gels (PWA/ICS−PPG or SiWA/ICS−PPG) were made from 3-isocyanatopropyltriethoxysilane and poly(propylene glycol)bis(2-aminopropyl ether), resulting in a hybrid silicon precursor (ICS−PPG) in which was dispersed phosphotungstic acid (PWA) or silicotungstic acid (SiWA) in ethanol. In this system, heteropoly acid takes on the additional role of catalyst, initiating the hydrolysis/condensation reactions of the sol−gel composite. The existence of amidonium ions [C(OH)NH+] was established from the IR and Raman spectra of PWA/ and SiWA/ICS−PPG composites below and close to the crystallization limits (70−75%). The crystallization of the Keggin ions inside the ICS−PPG host was determined from the XRD spectra of the composites and confirmed also using vibrational spectroscopy, which shows the appearance of H3O+ modes at 1700−1710 cm-1. The amidonium ions help in the immobilization of the negatively charged Keggin ions in the membranes, ensuring their uniform distribution in ...

Structure of and interactions between P/SiWA Keggin nanocrystals dispersed in an organically modified electrolyte membrane

Optically selective thin films of CoAl2O4 with a spinel structure were produced for an automotive lamps application by the sol-gel process using aluminum sec-butoxide, ethylacetoacetate chelating agent and cobalt nitrate hexahydrate. The use of two metal-oxide precursors is advantageous over the single bimetallic alkoxide precursor (aluminum cobalt isopropoxide), because it allows us to vary the Co/Al ratio in the precursor solution. We found that the Co/Al ratio should not exceed 0.3 if we are to achieve films with the characteristic blue colour at 700°C. The structural characteristics of the oxide powders were determined from infrared (IR) spectra and X-ray diffraction (XRD) analysis, while the optical properties of the films were investigated with UV-VIS spectroscopy.

Preparation and Spectroscopic Characterization of Blue CoAl2O4 Coatings

This paper reports on the development of all sol-gel EC devices, having the configuration WO3/ormolyte/SnO2:Mo, WO3/ormolyte/SnO2:Sb and WO3/ormolyte/SnO2:Sb:Mo, where all three internal layers, including the ionically conductive inorganic-organic hybrid (ormolyte), are prepared via the sol-gel route. The electrochemical and optical properties of EC devices are presented and their cycling stability and reversibility of their optical modulation assessed. The transmission modulation of the devices depends on the thickness of the active electrochromic, counter-electrode and ormolyte layer. The electrochemical and optical properties of individual films and the structural properties of the ormolyte are described and correlated with the stability of the all sol-gel EC devices.

All Sol-Gel Electrochromic Devices with Li+ Ionic Conductor, WO3 Electrochromic Films and SnO2 Counter-Electrode Films

Comparative studies of “all sol–gel” electrochromic devices with optically passive counter-electrode films, ormolyte Li+ ion-conductor and WO3 or Nb2O5 electrochromic films

U. Lavrenčič Štangar

Papers

Proton-conducting sol-gel hybrids containing heteropoly acids

Structure of and interactions between P/SiWA Keggin nanocrystals dispersed in an organically modified electrolyte membrane

Preparation and Spectroscopic Characterization of Blue CoAl2O4 Coatings

All Sol-Gel Electrochromic Devices with Li+ Ionic Conductor, WO3 Electrochromic Films and SnO2 Counter-Electrode Films

Comparative studies of “all sol–gel” electrochromic devices with optically passive counter-electrode films, ormolyte Li+ ion-conductor and WO3 or Nb2O5 electrochromic films