Person: Prado Gonjal, Jesús De La Paz
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First Name
Jesús De La Paz
Last Name
Prado Gonjal
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Inorgánica
Area
Química Inorgánica
Identifiers
7 results
Search Results
Now showing 1 - 7 of 7
Item SrCo0.50Fe0.40Ir0.10O3−δ decorated with Pd and La0.8Sr0.2Ga0.83Mg0.17O3−δ: a cleaner electrode for intermediate-temperature solid oxide fuel cells with reduced cobalt content(ACS Applied Energy Materials, 2024) Chivite-Lacaba, Mónica; Prado Gonjal, Jesús De La Paz; Troncoso, Loreto; Cascos Jiménez, Vanessa AmeliaRecent studies related to cathode materials for solid oxide fuel cells (SOFCs) have showcased the feasibility of stabilizing cubic or tetragonal perovskite phases in the SrCoO3−δ system at room temperature. This achievement has been facilitated by partially substituting Co atoms with small amounts of highly charged cations such as Ir4+ in SrCo0.90Ir0.10O3−δ. This specific material exhibits exceptional performance as a cathode for SOFCs operating at intermediate temperatures (800−850 °C). However, it contains a high amount of cobalt, which is both costly and toxic. In this study, our focus has been on further improving this material by reducing its cobalt content, resulting in a cleaner and more cost-effective cathode for SOFCs. The resulting SrCo0.50Fe0.40Ir0.10O3−δ perovskite, synthesized by the citrate method, introduces a 40% composition of Fe in the sites of Co and Ir, effectively decreasing the amount of Co in the material. The crystal structure of this perovskite oxide has been analyzed using X-ray diffraction (XRD) and neutron powder diffraction (NPD), allowing us to establish correlations with its mechanical and electrical properties. In the single-cell test, this material gave reasonable performances as a cathode at intermediate temperatures (800−850 °C), with La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) as the electrolyte. An analysis of the chemical compatibility between the cathode and the electrolyte, LSGM, demonstrated no interaction at elevated temperatures. Thermal expansion coefficient (TEC) measurements exhibited consistent linear expansion across the entire temperature range. Lastly, the perovskite displayed commendable electrical conductivity along with a promising power density measurement of 384 mW/cm2 at 850 °C. These findings collectively suggest the potential of this material as a viable cleaner cathode option for intermediate-temperature SOFCs. Moreover, the cathode was further optimized and the performance of the cell improved, by either infiltrating SrCo0.50Fe0.40Ir0.10O3−δ with a Pd(NO3)2 solution or mixing it with 30% of LSGM electrolyte, resulting in higher power densities (568 and 675 mW/cm2, respectively) in test cells fed with pure H2 as a fuel.Item Lithium‐filled skutterudites by intercalation at ambient‐temperature(Zeitschrift für anorganische und allgemeine Chemie, 2023) Prado Gonjal, Jesús De La Paz; Vaqueiro, Paz; Kowalczyk, Radoslaw; Smith, Ronald; Powell, AnthonyThe incorporation of lithium as a filler species in Co1‐2xFexNixSb3 skutterudites was accomplished by intercalation at 60 °C, using n‐BuLi as a reducing agent. Solid state 7Li NMR and ICP‐MS analysis confirm the presence of lithium in the product phases and provide an estimate of the lithium content. The maximum uptake of lithium increases as cobalt is progressively substituted by an equimolar mixture of iron and nickel. Difference Fourier maps, calculated during Rietveld structure refinement using powder neutron diffraction data, locate the lithium cations at the 2a (0,0,0) sites within the cavities of the skutterudite framework. The intercalation of lithium results in reductions in thermal conductivity of up to 47 %, indicative of phonon glass electron crystal (PGEC) type behaviour. Charge transfer from lithium to the framework that accompanies intercalation results in a substantial decrease in electrical resistivity in lithiated phases and a more metal‐like temperature dependence. The increased carrier concentration also decreases the Seebeck coefficient, with the consequence that modest increases in the figure of merit occur, despite the reduced thermal conductivity.Item From theory to experiment: BaFe0.125Co0.125Zr0.75O3−δ, a highly promising cathode for intermediate temperature SOFCs(Journal of Materials Chemistry A, 2020) Sánchez Ahijón, Elena; Marín Gamero, Rafael; Molero-Sánchez, Beatriz; Ávila Brande, David; Manjón-Sanz, Alicia; Fernández-Díaz, M. Teresa; Morán Miguélez, Emilio; Schmidt, Rainer; Prado Gonjal, Jesús De La PazIn a recent theoretical study [Jacobs et al., Adv. Energy Mater., 2018, 8, 1702708], BaFe0.125Co0.125Zr0.75O3−δ was predicted to be a stable phase with outstanding performance as an auspicious cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). It is shown here that the theoretical predictions are valid. The material can be synthesized by the citrate method as a single cubic Pm[3 with combining macron]m phase with a significant amount of oxygen vacancies, randomly distributed in the anionic sublattice facilitating oxygen vacancy conduction. A thermal expansion coefficient of 8.1 × 10−6 K−1 suggests acceptable compatibility with common electrolytes. Electrochemical impedance spectroscopy of symmetrical cells gives an area-specific resistance of 0.33 Ω cm2 at 700 °C and 0.13 Ω cm2 at 800 °C. These values are reduced to 0.13 Ω cm2 at 700 °C and 0.05 Ω cm2 at 800 °C when the material is mixed with 30 wt% Ce0.9Gd0.1O2−δ.Item Microwave-assisted synthesis of thermoelectric oxides and chalcogenides(Ceramics International, 2022) González-Barrios, Marta María; Tabuyo Martínez, Marina; Cascos Jiménez, Vanessa Amelia; Durá, Óscar Juan; Alonso, José Antonio; Ávila Brande, David; Prado Gonjal, Jesús De La PazThe combination of microwaves with other classical synthetic methods may be considered as a powerful tool for the preparation of metal oxides and metal chalcogenides. This approach allows the modification of the reaction kinetic significantly by shortening the processing time to minutes and it minimizes the energy consumption during the synthesis. In this work, potential thermoelectric compounds, which enable the direct conversion of temperature gradients into useful electric energy, have been produced by means of microwave-chemistry routes. Pure phases of SnS1-xSex (x = 0, 0.2, 1) have been synthesized in just 1 min by using microwave-hydrothermal synthesis. Moreover, Zn0.98M0.02O (M = Al, Ga) rods were formed by microwave-coprecipitation method in 5 min. Besides, 8 min of microwave-heating were enough for the combustion of Sr1-xLaxTiO3-δ (x = 0, 0.05, 0.1). In all cases, the utilization of microwave radiation produces high-quality phases. A comprehensive study of the structural, microstructural and thermoelectric properties of the microwave-synthesized materials is here performed by means of X-ray diffraction, SEM, HRTEM and temperature dependence measurements of Seebeck coefficient, electrical conductivity and thermal conductivity.Item Unveiling the Correlation between the Crystalline Structure of M‐Filled CoSb3 (M = Y, K, Sr) Skutterudites and Their Thermoelectric Transport Properties(Advanced Functional Materials, 2020) Gainza, Javier; Serrano‐Sánchez, Federico; Rodrigues, João ; Prado Gonjal, Jesús De La Paz; Nemes, Norbert Marcel; Biskup Zaja, Nevenko; Dura, Oscar ; Martínez, José ; Fauth, François; Alonso, JoséSkutterudite‐type pnictides based on CoSb3 are promising semiconductor materials for thermoelectric applications. An exhaustive structural characterization by synchrotron X‐ray powder diffraction of different M‐filled CoSb3 (M = Y, K, Sr, La, Ce, Yb) skutterudites, with a panoply of M atoms with very different chemical nature, allows to better understand the effects of filling from a crystallo‐chemical point of view. These analyses focus on the correlation of chemical and structural features with the enhanced thermoelectric properties displayed by certain families of filled‐CoSb3 skutterudites. These are mainly determined by Sb positional parameters, yielding Oftedal plots that depend on the filling fraction, ionic state, and atomic radius of the filler. Together with the distortion of [Sb4] rings and [CoSb6] octahedra present in the skutterudite structure, these results are linked to the band‐convergence concept and its influence on the thermoelectric transport properties. Here, the structural changes observed in the different chemical compositions are relevant to understand the improved thermoelectric performance of single partially filled n‐type skutterudites.Item SrCo0.50Fe0.40Ir0.10O3−δ Decorated with Pd and La0.8Sr0.2Ga0.83Mg0.17O3−δ: A Cleaner Electrode for Intermediate-Temperature Solid Oxide Fuel Cells with Reduced Cobalt Content(ACS Applied Energy Materials, 2024) Chivite-Lacaba, Mónica; Prado Gonjal, Jesús De La Paz; Troncoso, Loreto; Alonso, José Antonio; Cascos Jiménez, Vanessa AmeliaRecent studies related to cathode materials for solid oxide fuel cells (SOFCs) have showcased the feasibility of stabilizing cubic or tetragonal perovskite phases in the SrCoO3−δ system at room temperature. This achievement has been facilitated by partially substituting Co atoms with small amounts of highly charged cations such as Ir4+ in SrCo0.90Ir0.10O3−δ. This specific material exhibits exceptional performance as a cathode for SOFCs operating at intermediate temperatures (800–850 °C). However, it contains a high amount of cobalt, which is both costly and toxic. In this study, our focus has been on further improving this material by reducing its cobalt content, resulting in a cleaner and more cost-effective cathode for SOFCs. The resulting SrCo0.50Fe0.40Ir0.10O3−δ perovskite, synthesized by the citrate method, introduces a 40% composition of Fe in the sites of Co and Ir, effectively decreasing the amount of Co in the material. The crystal structure of this perovskite oxide has been analyzed using X-ray diffraction (XRD) and neutron powder diffraction (NPD), allowing us to establish correlations with its mechanical and electrical properties. In the single-cell test, this material gave reasonable performances as a cathode at intermediate temperatures (800–850 °C), with La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) as the electrolyte. An analysis of the chemical compatibility between the cathode and the electrolyte, LSGM, demonstrated no interaction at elevated temperatures. Thermal expansion coefficient (TEC) measurements exhibited consistent linear expansion across the entire temperature range. Lastly, the perovskite displayed commendable electrical conductivity along with a promising power density measurement of 384 mW/cm2 at 850 °C. These findings collectively suggest the potential of this material as a viable cleaner cathode option for intermediate-temperature SOFCs. Moreover, the cathode was further optimized and the performance of the cell improved, by either infiltrating SrCo0.50Fe0.40Ir0.10O3−δ with a Pd(NO3)2 solution or mixing it with 30% of LSGM electrolyte, resulting in higher power densities (568 and 675 mW/cm2, respectively) in test cells fed with pure H2 as a fuel.Item Cellulose nanocrystal-derived carbon electrodes for sustainable potassium-ion charge storage systems(Sustainable Materials and Technologies, 2024) Ojeda Fernández, Irene; Arenas, Cristian B.; Calle-Gil, Raúl; Ebrahimi-Koodehi, Soheila; Garcia-Gimenez, Daniel; José Torralvo, María; Prado Gonjal, Jesús De La Paz; Carretero-González, Javier; Castillo Martínez, ElisabetWe have here produced carbon electrode materials derived from Crystalline NanoCellulose (CNC) for low-cost potassium-ion based energy storage systems through conventional annealing as well as through a fast and energy efficient microwave assisted carbonization process. A two-step 4-minute synthesis with ZnCl2 activation in a domestic microwave leads to a micro/mesoporous carbon with high surface area (SBET~1800 m2 g 1). These CNC-derived carbons, if assessed in symmetric supercapacitor C/C cells cycled with 0.5 M K2SO4 aqueous electrolyte, show reversible capacitance values up to 66 F g 1 at current densities of 5 A g 1, retaining 83% of its initial capacitance after 10.000 cycles without any conducting additive. Due to its large electrochemical window of 1.7 V, a competitive energy density for an aqueous system of 20.9 W h kg 1 is achieved. A hybrid aqueous capacitor built with this carbon as negative electrode and coupled with a Prussian White as positive results in cell capacitance values up to 135 F g 1 under a voltage operation window of 1.8 V in 0.5 M K2SO4. On the other hand, non-activated carbons produced through a 2.25 hour thermal annealing at 900 ◦C, present much lower surface area (SBET~450 m2 g 1), most of it due to its high micropore volume. This low external and mesoporous surface area carbon is a competitive anode material for potassium-ion batteries with a reversible capacity of ~200 mA h g 1 cycled at 28 mA g 1 using 3.9 M KFSI in DME electrolyte (favourably most of it below 1 V vs K+/K) in a potassium half-cell with >80% retention in 100 cycles. The present research shows that sustainable CNC derived carbons produced through energy efficient methods are competitive electrode materials in low-cost K based energy storge systems.