RT Dissertation/Thesis
T1 Microstructural tailoring of nanocomposite electrodes for solid oxide fuel cells
A1 Zamudio-García, Javier
K1 Pilas de combustible - Tesis doctorales
AB The high demand for electrical energy induced by the rapid population growth has arisen the necessityto develop sustainable and environmentally friendly energy sources. In this context, fuel cells are one of the mostpromising technologies to obtain electrical energy from a wide variety of fuels with good efficiencies and loweremission of pollutants. In particular, Solid Oxide Fuel Cells (SOFCs) have attracted great attention in recent yearsdue to their fuel flexibility, good tolerance to impurities in the fuel and higher efficiencies.However, the high operating temperatures of SOFCs (600-800 ºC) needed to achieve a good electrode performanceand a sufficient ionic conductivity for the electrolyte, negatively affect the long-term stability of these devices. Forthis reason, decreasing the operating temperature is one of the main goals for the wide implementation of SOFCs. Itis well known that the crystal structure and composition of the electrodes play a key role in the electrochemicalperformance; nevertheless, the microstructural optimization of the electrodes has demonstrated to be crucial toboost the electrochemical properties at low operating temperatures in both oxidizing and reducing conditions.In this PhD thesis, different nanostructured and nanocomposite electrode layers based on the combination ofperovskite-type electrodes, i.e. LaCrO3, SrTiO3 or LaFeO3 and the ionic conductor Ce0.9Gd0.1O1.95 (CGO) withfluorite-type structure have been prepared and tested for their implementation in SSOFCs. The electrode layerswere prepared directly onto Zr0.84Y0.16O1.92 (YSZ) or La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) electrolytes byspray-pyrolysis. Additionally, pulsed laser deposition (PLD) was employed for the preparation of active layers. Forcomparison purposes, the same electrode compositions were prepared as powders from freeze-dried precursorsand then deposited onto the electrolyte by screen-printing method.
PB UMA Editorial
YR 2023
FD 2023
LK https://hdl.handle.net/10630/28625
UL https://hdl.handle.net/10630/28625
LA eng
NO The results revealed that La0.98Cr0.75Mn0.25O3-δ-CGO and (La0.8Sr0.2)0.95Fe0.8Ti0.2O3-δ-CGO are promisingelectrodes for symmetrical SOFCs with good electrochemical properties and durability in both oxidizing andreducing atmospheres. In particular, La0.98Cr0.75Mn0.25O3-δ-CGO exhibits polarization resistance of 0.09 Ω cm2at 700 ºC in H2, comparable to the state-of-the-art Ni-YSZ anode.Nanocomposite active layers were also prepared by spray-pyrolysis deposition to improve the ORR activity of aLSM cathode. Among the different compositions, LSM-CGO layers showed improved adherence and electricalproperties. The incorporation of this active layer enhances the ion transfer at the cathode/electrode interface andalso extended the ionic/electronic conducting paths for electrochemical reactions. A Ni-YSZ/YSZ/LSM-CGO/LSManode-supported cell showed a maximum power density of 1200 mW cm-2 at 800 ºC compared to 790 mW cm-2 forthe same cell without an active layer.Vertically Aligned Nanostructures (VANs) of (La0.8Sr0.2)0.98Fe0.8Ti0.2O3−δ-CGO and(Sr0.7Pr0.3)0.95Ti0.9Ni0.1O3−δ-CGO were prepared by PLD for their implementation as redox stable active layersfor SOFCs. The heteroepitaxial films exhibited long-range columnar architecture of 5 nm width. The VAN filmsshowed higher conductivity than that observed for the polycrystalline samples.
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 20 ene 2026