A nanostructured three-dimensional (3D) microbattery has been produced and cycled in a Li-ion battery. It consists of a current collector of aluminum nanorods, a uniform layer of 17 nm TiO(2) covering the nanorods made using ALD, an electrolyte and metallic lithium counter electrode. The battery is electrochemically cycled more than 50 times. The increase in total capacity is 10 times when using a 3D architecture compared to a 2D system for the same footprint area.

CO adsorption on carbon-supported Pt nanoparticles under operando conditions was studied by quadrupole mass spectrometry and diffuse reflectance infrared fourier transform spectroscopy (DRIFTS). The Pt catalyst was also studied by high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). It was shown by HRTEM and XPS that Pt nanoparticles can be fully reduced by H2 at room temperature instead of by conventional high-temperature treatment. The Pt dispersion was determined by XRD, HRTEM, and CO chemisorption techniques with an excellent agreement among them. The room-temperature H2/O2 titration method was also used, but if assuming H/PtS = O/PtS = 1, it led to the underestimation of the dispersion compared to the other techniques. The existence of adsorption sites inaccessible to H2 (or O2) but accessible to CO because of a stronger interaction with Pt was proposed to explain the results. It was also concluded that H/Pts was lower than unity (H/Pts = 0.72) and, as a major consequence, that Pt nanoparticles with 2.7 nm diameter still have a bulk-like behavior in contrast with what was reported in the literature for 1 nm Pt particles. CO adsorption on Pt/C at 298 K after H2 treatment was studied by operando DRIFTS. The C–O stretching vibration (νCO) bands were ascribed to CO adsorbed on Pt surface at (111)-terrace, (100)-terrace, edge, and kink sites in linear and bridge forms. An unexpected νCO band at 1703 cm–1 was observed upon CO adsorption and tentatively attributed to CO on surface Pt sites interacting through its oxygen end with the carbon support. It was also shown that the adsorption of CO and H2 in successive repeated steps was necessary to reach a stable state of the adsorbed CO phase. Possible reconstruction of Pt nanoparticles at room temperature during this process is discussed.

A novel architecturally designed LaPrNiO4+δ IT-SOFC cathode shows the best compromise between thermodynamic stability and electrochemical properties.

In this paper we discuss a comprehensive physical-based model of the PEMFC materials degradation allowing predicting the MEA durability as function of the operation conditions, initial material loadings and electrodes microstructure. The approach, build within a modular multiscale non-equilibrium thermodynamics framework, couples atomistic-based descriptions of catalyst contamination/oxidation/dissolution/ripening, dissolved catalyst migration in the ionomer, C catalyst-support corrosion and chemical PEM degradation, with the degradation-induced nano/microstructural and transport properties (of reactants and charges) evolution. By describing the feedback between the instantaneous performance and the material aging phenomena, the model provides new insights on the competition between the different degradation processes under automotive-operating conditions. The predictive capabilities of our approach are illustrated in this paper through four applicative examples: 1) PtxCoy catalysts degradation 2) competition of PEM and cathode C degradation 3) synergies between anodic CO contamination and PEM and cathode C degradation, and 4) synergies between Pt and C degradation.

ENERGIE+KIC:PG

In this paper, based on a multiscale modelling framework, we focus on understanding the impact of CO adsorption on the intrinsic stability properties of PtxCoy nanoparticles under PEMFC anode operating conditions. First, CO adsorption effect on PtxCoy has been studied by using Monte Carlo (MC) simulation. Then, the MC results are coupled with an ab initio based kinetic model to simulate the effect of CO poisoning on the activity and durability of the PtxCoy nanoparticles as HOR catalysts. The results are compared with simulations carried out with pure Pt, where potential self-oscillatory behaviour is detected and experimentally confirmed. The PtxCoy HOR activity and stability reveals to be strongly dependent on the nanoparticle size and composition. For some nanoparticle sizes, simulations show that PtCo nanoparticles provide better CO tolerance than Pt3Co. CO adsorption on PtCo slows down Co dissolution in short-term operation. However, this effect is overcome by the increase of the anode potential due to CO adsorption. Thus, CO adsorption enhances Co dissolution in long-term operation. Due to this Co dissolution, the HOR activity of PtCo degrades faster than Pt3Co in long-term operation.

In this contribution, we report investigation of metal supported cells with a La0.1Sr0.9TiO3–α (LST) based fuel electrode. The cells are prepared on a substrate made of a porous NiCrAl metal foam infiltrated with NiO and LST materials. The functional anode layer, consisting of LST mixed with a Gd0.1Ce0.9O2–α (GDC), is produced by screen printing. Nickel metal is infiltrated in the backbone to enhance electronic and catalytic properties. The electrolyte made of an 1 μm + 0.5µm thick Zr0.84Y0.16O2–α (YSZ) layer followed by a 2 μm thick GDC layer, is fabricated by wet ceramic processing and electron beam physical vapor deposition (EB‐PVD), respectively. La0.6Sr0.4Co0.2Fe0.8O3–α (LSCF) is employed as a cathode material. All cells are electrochemically characterized. At 750 °C and at a cell voltage of 0.7 V, the typically achieved power density value is up to 0.40 W cm−2. With less than 2% variation for 50 cycles, the OCV showed an excellent stability as a function of redox cycles, demonstrating that an electrolyte as thin as 3 µm maintains its integrity, despite the harsh operating conditions. This highlights the potential of perovskite based fuel electrodes in metal supported cells, and paves the way to the next generation of cells' design.

The CO oxidation reaction on carbon-supported Pt nanoparticles (average size of 2.8 to 7.7 nm) was studied under flowing conditions at atmospheric pressure and temperatures between 300 and 353 K by coupling quadrupole mass spectrometry (QMS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The Pt loading was varied between 20 and 60 wt%. Gases diluted in He (0.5 mol%) were used together with Ar as a tracer. Reactions with CO and O2 introduced separately onto the samples were studied by QMS, applying successive step changes of the reaction mixtures. Variations in the rate of the reactions were observed and correlated with changes of the calculated coverage of the Pt surface by CO and/or O adspecies at varying steps of the experiment. The transient reaction of CO(g) with adsorbed O (Oad) was fast and mass transport-limited while that of O2(g) with adsorbed CO (COad) was sluggish. Following the same experimental procedures, FTIR spectra of adsorbed CO after varying steps were recorded, confirming the variations of COad and Oad as determined by QMS and indicating changes in the CO distribution over varying types of Pt surface sites. The influence of the adlayer composition (co-adsorption of COad and Oad), the particle size/structure and some possible surface reconstruction effects on the CO oxidation rate were evidenced and discussed. The structure of the Pt nanoparticles supported on carbon appears as an important factor for the efficiency of the so-called O2 bleeding as a CO mitigation strategy in polymer electrolyte membrane fuel cells.