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Materials are always among the first considerations to the development of low temperature solid oxide fuel cells (SOFCs). In this study, we investigate the multifunctionality of a layer-perovskite oxide La2-xCexCuO4 (LCCO) for its applications in SOFC as cathode, anode and electrolyte. The performances of the LCCO cathode and anode fuel cells are characterized by I–V–P and electrochemical impedance spectra (EIS). Results suggest that LCCO is a good cathode material and it can also deliver impressive anode performance. Though LCCO is noticed to be reduced by H2 in the anode, the cell performance is relatively stable under multiple times of operation. The existing of ceria and reduced Cu in it may be a reason for its anode catalytic activation. For the application in electrolyte, LCCO is mixed with ionic conductor Ce0.8Sm0.2O2-δ (SDC) in different weight ratios. Differences in power output and open circuit voltage for the cells containing various ratios of LCCO under normal and reverse operation conditions are highlighted. The electronic conductivity of LCCO doesn't bring in electronic leakage if it is kept in a certain range. The multifunctionality of LCCO would enable it to be potentially applied in single layer fuel cell to simplify the structure and fabrication process of SOFC.

Electrolyte densification, which is often realized by high temperature sintering (i.e. >1000 °C), is an essential process for solid oxide fuel cell (SOFC). However, it is hard to achieve interfaces with high ionic conductivity because the interfaces between particles would be greatly eliminated during the sintering process. In this study, a novel interface engineering method is designed basing on capillary action to densify the electrolyte and at the meantime achieve ionic conductive interfaces at low temperature. A porous electrolyte layer is found to become dense during fuel cell operation when alkali metal hydroxide (AMH) is added to the NiO anode. The observation of improved open circuit voltage (OCV) indicates gas leakage has been eliminated after AMH modification. Raman images confirm that AMHs can be absorbed into the electrolyte layer when the operating temperature is higher than the melting point of AMH. In addition, using a lithiated metal oxide (i.e. LiNiO2) as the anode, cell performance is further improved. EIS proves that the existing of AMH in the cell may affect gas diffusion in the electrode, but it significantly reduces ohmic resistance due to better interfacial ionic conductivity of the electrolyte. This in-situ electrolyte densification method not only enables us to simplify fuel cell fabrication process and lower the fabrication temperature but also provides ways for maintaining interface conductivity.

Layered nonstoichiometric vanadium oxides have aroused strong interest in energy conversion, storage, chemical catalysis, sensors, and optoelectronic devices. It is still a critical challenge to control unique atomic-layer constructions and oxygen-dependent multivalent states in layered metal oxides. Here, we demonstrate the layered nonstoichiometric V7O16 thin films with controlled multivalent states and crystalline phases obtained by the combination of atomic layer deposition (ALD) and oxygen-dependent crystallization. The nonstoichiometric composition and crystalline microstructures are dominated by the oxidation states of vanadium and the thicknesses of the pristine films during the formation of layered V7O16 thin films. Variable-temperature optical and electrical behaviors suggest that no abrupt electronic and structural transitions are observed in the layered V7O16 thin films at a temperature ranging from 78 to 475 K. We expect that the oxygen-dependent multivalent states and crystalline phases in l...

Li+ plays a critically important role in layer-structured LiNiO2 family oxides in that it affects the oxidant state of Ni and catalyst's function. Layer-structured LixNi0.8Co0.15Al0.05O2-δ (LxNCA, x = 1, 1.2, 1.4) with different lithium content was prepared and applicated as both cathode and anode catalysts in symmetrical solid oxide fuel cell (SSOFC) that using samarium doped ceria (SDC) as electrolyte. Excess Li precursor resulted in the formation of Li2CO3 in L1.2NCA and L1.4NCA materials, whose influence on the performance of LxNCA was studied. Oxygen reduction reaction (ORR) and hydrogen oxidation reaction (HOR) of LxNCA as well as its catalytic stability were investigated by impedance spectroscopy. Its ORR process was found to be greatly influenced by the amount of Li in LxNCA while HOR was less related to Li content. Accompanying the on-line reduction and oxidation of LxNCA, fuel cells tested under reverse operation condition revealed enormous improvement in Pmax, which was due to the significant improvement of ORR process and the reduction of interface resistance.

Controlling the surface is necessary to adjust the essential properties and desired functions of nanomaterials and devices. For nanostructured multivalent vanadium oxides, unwanted surface oxidation occurs at ambient atmosphere generally and needs to be suppressed or avoided. We describe the suppressed surface oxidation of VO2 nanostructures through blocking oxygen adsorption. During an enhanced photoinduced surface oxidation process, the increased oxidation states of vanadium in VO2 nanostructures are suppressed by the use of an inert atmosphere or coating. Intermediate oxidation states are observed, and an ALD-TiO2 coating has a good antioxidant capacity for preventing the formation of oxygen-enriched components. Such oxidation suppression is beneficial to improving the stability of VO2 nanostructures. Controllable surface oxidation helps us to understand the physical essentials of surface chemical reactions and achieve better control of surface functions and performances on correlated vanadium oxide nanostructures.

Long-term stability is of significant importance to energy conversion devices including solid oxide fuel cell (SOFC). In this work, we apply a layered perovskite oxide La1·85Sr0·15CuO4 (LSCO4) mixing with ionic conductor Ce0.8Sm0.2O2-δ (SDC) to get an ionic and electronic conductor composite (IECC) membrane SOFC for the sake of achieving a stable cell. The addition of proper ratio of LSCO4 in the membrane improves cell performance. The IECC fuel cell reaches a stability of over 75 h at 550 °C under 100 mAcm−2 and can resist multiple times of rapid heat-up and cool-down cycles. The factors that influence cell stability are investigated. The covalence states of the IECC are found to change firstly but stabilize after several hours of test. Resulting from anode Ni0·8Co0·15Al0·05LiO2-δ (NCAL) reduction, Li+ is found to migrate to the IECC membrane, leading to IECC membrane densifying and resultantly protecting the IECC from further reduction by hydrogen. However, the continuous online reaction of NCAL electrodes leads to the increase of charge transfer resistance as well as the decrease of gas diffusion pores in the electrode. This study provides important reference for designing stable IECC membrane fuel cell.

The aim of this study was to introduce human somatostatin receptors subtype-2 (hsstr2) gene into A549 lung carcinoma cells in order to investigate the role of these receptors, and to observe the lethal effect of (131)I-RC-160 (RC-160, vapreotide, an analog of somatostatin) on transfected cells through tumor scintigraphy. Clones overexpressing SSTR2 were selected for radioligand-receptor binding assay and assessment of (125)I-RC-160 internalization. The methylthiazolyl tetrazolium test was used to observe the lethal effect of (131)I-RC-160, Na(131)I, and RC-160 on hSSTR2-transfected A549 cells (A549-hSSTR2). Planar imaging was performed with a gamma camera equipped with pinhole collimator in nude mice bearing both A549-hSSTR2 tumors overexpressing SSTR2 and A549-pcDNA3 (pcDNA3-transfected A549 cells) tumors as control. Images were obtained at 0.5, 6, and 24 h after injection of 3.7 × 10(6) Bq (99m)Tc-RC-160 via the tail vein. The inhibitory effects of (131)I-RC-160, RC-160, and Na(131)I on the tumors were recorded by measuring the tumor volumes. At the end of the study, the tumors were excised and HE staining was performed. The binding radioactivity (sum of membrane-bound and internalized radioligand) of A549-hSSTR2 cells was 18.24 ± 1.9 % of total counts added after 1 h of incubation, and was higher than that of A549-pcDNA3 cells 5.7 ± 1.4 % (P < 0.05). The inhibition ratio of A549-hSSTR2 cells was 78.8 ± 5.9 %. Clear images of tumor lesions in nude mice were achieved at 0.5 h post injection. In the A549-hSSTR2 xenograft tumor group, the growth of the tumors treated with (131)I-RC-160 was significantly inhibited as compared to tumors in the group treated with RC-160 (P < 0.01). This study demonstrated that it was possible to introduce hsstr2 to non-expressing tumor cell lines and treat tumors with radiolabeled somatostatin analogs.