Papers by Keyword: Composite Electrolyte

Abstract: The LSGM-carbonate composite electrolyte is a new type of medium and low temperature SOFC electrolyte material, which has great application potential. In this paper, the molten salt infiltration method was used to prepare the LSGM-carbonate composite electrolyte. The results of SEM test proved that the molten salt infiltration method was more appropriate in preparing the LSGM-carbonate composite electrolyte comparing with direct mixing method. The influence of the type and content of pore forming agent was investigated. The result showed that the polymethyl methacrylate (PMMA) had an excellent pore forming performance and could create interconnected pore structures successfully in LSGM matrix. The XRD result indicated that the LSGM-carbonate composite electrolyte showed almost a single LSGM phase and the carbonate remained glass state. Four terminal method was used to measure the conductivity. The result showed that the conductivity of the LSGM-carbonate composite electrolytes was increased by one order of magnitude compared with pure LSGM. The conductivity of LSGM-carbonate composite electrolytes increased firstly and then decreased with the increasing of PMMA. The LSGM-carbonate composite electrolyte prepared by 25 wt.% PMMA addition has the highest conductivity during the whole range of test temperature and reached 0.3 S.cm^-1 at 600°C.

Abstract: Observation on the effects of rare earth impurities on the properties of Ce_0.9Gd_0.1O_0.195 (GDC) composite electrolyte has been performed. Indonesia has abundant rare earth elements especially CeO₂, which one of the resources is from monazite mineral. In this study, the GDC powders were synthesized via solid state technique. The two types of precursors were prepared and mixed into planetary ballmill, i.e., CeO₂ (Sigma Aldrich) with Gd₂O₃ (Sigma Aldrich) and CeO₂ (non-commercial, local product) with Gd₂O₃ (Sigma Aldrich), namely GDC commercial and GDC non-commercial, respectively. The composite electrolyte powders calcined at temperature of 800°C in the air atmosphere condition. The composite electrolytes were then characterized in terms of its morphology, elemental, phase structure and thermal properties of the powders. The GDC commercial and non-commercial powders both consist of face centered cubic fluorite ceria structure which was confirmed by X-Ray Diffraction (XRD). The peaks are matching well with the cerium oxide JCPDS card No: 34-394. There are no peaks detected for the gadolinium oxide. It indicates that the dopant ion is fully substituted into the CeO₂ lattice. The elemental analysis was performed using X-ray Fluorescence (XRF). The microstructures were observed under Scanning Electron Microscopy (SEM). The thermal properties characterizations were performed by using Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) from room temperature to 1500°C. Both powders investigated are suitable for electrolyte IT-SOFC based on their physical and thermal characterization. Among the composite electrolytes investigated, the GDC commercial showed the better performance in terms of their physical and thermal properties.

Abstract: LSGM(La0.9Sr0.1Ga0.8Mg0.2O3-δ)-carbonate composite electrolyte was prepared by molten salt infiltration method and its properties were analyzed by scanning electron microscope (SEM), X ray diffractometer (XRD) and A.C. impedance. LSGM-carbonate composite electrolyte showed the same phase patterns as pure LSGM which suggests carbonates exist in an amorphous state. SEM images of porous LSGM pellet indicated all of the pores are uniformly distributed and nearly all of them are connected with each other. The A.C conductivity measurements showed composite electrolyte possessed a much higher ionic conductivity than LSGM electrolyte at a temperature within the range of 450-650 oC. Conductive highways for oxygen ions and multi-ions conduction were employed in explaining the improved property of composite electrolyte.

Abstract: All-solid-state composite polymer electrolyte is a multiphase material that adopted an organic polymer as the main matrix. Performance improvement of electrolyte materials can be achieved by complexation between functional groups from the polymer molecular chain and the ions and, by adjusting the component and proportion of polymer and modified filler. This manuscript presents a new idea for preparation composite polymer electrolyte based on the poly (ethylene oxide). We use scanning electron microscopy (SEM), AC impedance measurements etc. to character the polymer electrolyte and their properties. We observed a very large improvement of ion conductivity by adding appropriate content of dropping fillers.

Abstract: The e-beam irradiation technique was found to be a new efficient method to improve and control the morphological and electrochemical properties of composite electrolytes of polyethylene oxide (PEO) and TiO2 for dye-sensitized solar cell (DSSC). PEO was irradiated by electron beam (e-beam) with energy source 2 MeV from 60 to 240 kGy doses at the dose rate of 15 kGy/min. The transition and amorphous phases of PEO were significantly increased upon the e-beam irradiation. Optimum e-beam irradiation was 60kGy in terms of degree of cross linking and amorphicity for the efficient ion conduction electrolytes. However, the properties of polymer and composite electrolytes were deteriorated after irradiation of > 60 kGy. The prepared composites with PEO/60kGy and TiO2 (PEO/60kGy-TiO2) showed significantly improved morphological and ionic conductivity properties of electrolyte for DSSC. DSSC fabricated with PEO/60kGy-TiO2 showed drastically increased conversion efficiency of 4.52% as compared to DSSC fabricated with bare PEO (conversion efficiency = 1.9%).

Abstract: Composites consisting of Ce0.8Sm0.2O1.9 (SDC)-carbonate were developed as electrolytes for low temperature solid oxide fuel cells (LTSOFC). The SDC power was prepared by sol-gel method. The carbonates were binary eutectics of (Li/Na)2CO3, (Li/K)2CO3 and (K/Na)2CO3. Conductivity measurements showed that the conductivities were depended on the type of carbonates. Discontinuities were found in the Arrhenius plots for both SDC-(Li/Na)2CO3 and SDC-(Li/K)2CO3. For SDC-(Na/K)2CO3 composite electrolyte, the conductivity increased as temperature rose following one slope. Single cells based on various composites were fabricated by a uniaxial die-press method and tested at 450-600 oC. The results showed all cells exhibited improved performances upon that of pure SDC-based cell. The best power density of 532 mW cm-2 at 600 oC was achieved for LTSOFC using composite of SDC and (Li/Na)2CO3. Conductivity mechanism was also discussed.

Abstract: A kind of novel composite electrolyte, consisting of zinc doped ceria and carbonates, was developed. The phase and morphology of the composite material were characterized. Ceramic fuel cells based on this composite electrolyte were constructed with two techniques. The hydrogen-air fuel cell fabricated with anode-supported technique showed relative low open circuit voltages (OCVs) and high output performance, but the electrolyte-supported one exhibited relative high OCVs and low output performance. During the fuel cell operation, water was observed at both anode and cathode sides, indicating hybrid ions conduction lies in the composite electrolyte under fuel cell environment.