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The electrochemical performance of non-aqueous lithium-oxygen batteries depends largely on the catalytic activity of the cathode, among which the architecture design plays an important role. In this paper, we present a novel free-standing, flexible cathode with needle-like NiCo2O4 coated on a three-dimensional graphene framework. The hierarchical structure exhibits a macropore nest of graphene foam along with mesopore decoration of NiCo2O4 nanorods, which can provide fast diffusion or adsorption for the reactants and abundant active site for the oxygen reduction reaction and oxygen evolution reaction. With the novel cathode, the battery delivers a capacity about 5000 mAh g−1 at a current density of 400 mA g−1, and can cycle stably at least 80 times without obvious degradation at the capacity limitation of 1000 mAh g−1. This flexible cathode shows potential application in foldable electronic devices. [ABSTRACT FROM AUTHOR]

A simple and accurate immune sensor for quantitative detection of α-Fetoprotein (AFP) was developed based on the immobilization of antigen on the surface of Hep-PGA-PPy nanoparticles modified glassy carbon electrodes (GCE). The obtained Hep-PGA-PPy nanoparticles were characterized by fourier transform infrared (FT-IR) spectra and transmission electron microscopy (TEM). And the blood compatibility of Hep-PGA-PPy nanoparticles was investigated by in vitro coagulation tests, hemolysis assay and whole blood adhesion tests. Combining the conductive property of polypyrrole (PPy) and the biocompatibility of heparin (Hep), the Hep-PGA-PPy nanoparticles could improve not only the anti-biofouling effect the electrode, but also improved the electrochemical properties of the immune sensor. Under optimal conditions, the proposed immune sensor could detect AFP in a linear range from 0.1 to 100 ng mL −1 with a detection limit of 0.099 ng mL −1 at the signal-to-noise ratio of 3, and it also possessed good reproducibility and storage stability. Furthermore, the detection of AFP in five human blood samples also showed satisfactory accuracy with low relative errors. Thus, the developed immune sensor which showed acceptable reproducibility, selectivity, stability and accuracy could be potentially used for the detection of whole blood samples directly. [ABSTRACT FROM AUTHOR]

In this paper, the deposition of Ni–Co alloy coating on Cu substrate was prepared by cyclic voltammetry method. The Ni–Co coating was measured by XRD, SEM and EDS to determine the composition and morphology. The deposition of Ni–Co alloy is anomalous deposition, that is, the ratio of Ni–Co in alloy is not equal to that in the deposition bath. With the increase of cyclic times, the content of Co increases. Polarization curves and AC impedance measurement show that the alloy coating electrodes are more active than the Ni electrode. With the content of Co increase in the alloy coating, the electrocatalytic activities of the alloy coating increase. Heat treatment can also improve the properties of alloy coating for OER. [Copyright &y& Elsevier]

The application of cobalt-based perovskite cathode materials in proton-conducting SOFCs (H–SOFCs) is challenged by their high thermal expansion coefficient (TEC). To address interface degradation/separation between the cobalt-based perovskite cathode and the proton-conducting electrolyte, we design and prepare the high-entropy perovskite oxide (HEPO) BaCo 0.2 Zn 0.2 Ga 0.2 Zr 0.2 Y 0.2 O 3-δ (BCX) as the cathode for proton-conducting SOFCs (H–SOFCs). BCX demonstrates remarkable performance and stability in the oxygen reduction reaction, validated through structural analysis and electrochemical characterizations. The TEC of BCX is as low as 12.75 × 10-6 K−1 compared to the 18.69 × 10-6 K−1 of the un-doped BaCoO 3-δ (BC). The polarization resistance of BCX cathode about 0.69 Ω cm2 is realized at 600 °C, much lower than that for pristine BC cathode (1.27 Ω cm2). Cell with BCX cathode exhibits remarkable long-term stability without detectable degradation over 100 h. [ABSTRACT FROM AUTHOR]

Tubular solid oxide fuel cells were fabricated and evaluated for their microstructure and electrochemical performance. The tubular substrate was prepared by casting NiO-Y2O3 stabilized ZrO2 (YSZ) slurry on the inner wall of a plastic mold (tube). The wall thickness and uniformity were controlled by slurry viscosity and rotation speed of the tube. The cells consisted of Ni-YSZ functional anode, YSZ electrolyte and (La0.8Sr0.2)0.95MnO3-δ (LSM)-YSZ cathode prepared in sequence on the substrate by dip-coating and sintering. Their dimension was 50 mm in length, 0.8 mm in thickness and 10.5 mm in outside diameter. The peak power density of the cell at temperatures between 650 and 850°C was in the range from 85 to 522 mW cm−2 and was greatly enhanced to the range from 308 to 1220 mW cm−2 by impregnating PdO into LSM-YSZ cathode. During a cell testing at 0.7 A cm−2 and 750°C for 282 h, the impregnated PdO particles grew by coalescence, which increased the cathode polarization resistance and so that decreased the cell performance. According to the degradation tendency, the cell performance will be stabilized in a longer run. [ABSTRACT FROM AUTHOR]

Abstract: The anode material BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) for solid oxide fuel cells (SOFCs) is prepared by solid state reaction method and its chemical compatibility with Y2O3 stabilized ZrO2 (YSZ) is evaluated. The electrochemical performance of the pure and Pd- and Cu0.5Pd0.5-impreganated BZCYYb electrodes is characterized in the temperature range between 650 and 750°C by AC impedance spectroscopy in H2 and/or CH4 atmospheres, respectively, under the condition of open circuit. It is confirmed that the BZCYYb is chemically compatible with the YSZ at temperatures below 1000°C. The polarization resistance of the BZCYYb anode in H2 is decreased from 2.08 to 0.51Ωcm2 as the measuring temperature increases from 650 to 750°C with an activation energy of 117kJmol−1. With Pd- or Cu0.5Pd0.5-impregnation, the polarization resistance of the BZCYYb electrode in H2 is reduced significantly to approximately 0.40Ωcm2 at 650°C and 0.12Ωcm2 at 750°C. With dry CH4 as the fuel, the polarization resistance of the Pd- and Cu0.5Pd0.5-impregnated BZCYYb anodes is obviously increased below 1.00Ωcm2 at 650°C and 0.22Ωcm2 at 750°C. Both Pd and Cu0.5Pd0.5 impregnations are equivalently effective in enhancing the electrochemical performance of the BZCYYb anode. [Copyright &y& Elsevier]

Cr-poisoning effect on pure double-perovskite PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF) cathode and La 2 NiO 4+δ (LN)-coated PBSCF cathode is investigated. During the Cr poisoning test at 750 °C in the presence of SUS430 interconnect, the electrochemical performance of pure PBSCF cathode shows severe degradation, and the significant increase in R P is mainly contributed by the increased R L . The BaCrO 4 deposits are identified on the PBSCF cathode surface. LN-coated PBSCF cathode, by contrast, shows remarkable tolerance towards chromium. The reaction between volatile Cr species and PBSCF cathode can be prevented by a dense LN coating. Thus, a more stable electrochemical performance is achieved by LN-coated cathode during the Cr poisoning test. The results indicate that the introduction of LN coating not only improves the cathode electrochemical performance, but also prevents the cathode from being poisoned by chromium. [ABSTRACT FROM AUTHOR]

High-temperature H 2 O/CO 2 co-electrolysis through reversible solid oxide electrolysis cell (SOEC) provides potentially a feasible and eco-friendly way to convert electrical energy into chemicals stored in syngas. In this work, La 0.8 Sr 0.2 Co 0.8 Ni 0.2 O 3-δ (LSCN) impregnated Gd 0.1 Ce 0.9 O 1.95 (GDC)-(La 0.8 Sr 0.2 ) 0.95 MnO 3-δ (LSM) composite oxygen electrode is studied as high-performance electrode for H 2 O/CO 2 co-electrolysis. The LSCN impregnated cell exhibits competitive performance with the peak power density of 1057 mW cm −2 at 800 °C in solid oxide fuel cell (SOFC) mode; in co-electrolysis mode, the current density can reach 1.60 A cm −2 at 1.5 V at 800 °C with H 2 O/CO 2 ratio of 2/1. With LSCN nanoparticles dispersed on the surface of GDC-LSM to maximize the reaction active sites, the LSCN impregnated cell shows significant enhanced electrochemical performance at both SOEC and SOFC modes. The influence of feed gas composition (H 2 O-H 2 -CO 2 ) and operating voltages on the performance of co-electrolysis are discussed in detail. The cell shows a very stable performance without obvious degradation for more than 100 h. Post-test characterization is analyzed in detail by multiple measurements. [ABSTRACT FROM AUTHOR]

La 2 NiO 4+δ (LN)-coated PrBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ (PBSCF) composite cathode, designated as PBSCF-LN, for the intermediate temperature solid oxide fuel cells (IT-SOFCs) is prepared by solution infiltration, and investigated comparatively with single phase PBSCF cathode in the half and full cells using Ag and/or Pt paste as the current collector. Compared with Pt, Ag current collector results in a decrease of cathode polarization resistance ( R P ) by an order of magnitude, which suggests that Ag is electrocatalytically active and not suitable for the use of studying the cathode performance of IT-SOFCs. The R P value of PBSCF-LN cathode is significantly lower than that of PBSCF cathode, no matter whether Pt or Ag current collector is used for the measurement. High power densities ranging from 0.24 to 0.94 W cm −2 at temperatures between 600 and 750 °C are achieved using a full cell with PBSCF-LN cathode. Upon exposure to a CO 2 -rich atmosphere, carbonate particles are formed on the surface of PBSCF cathode, causing irreversible degradation of electrochemical performance. In contrast, the surface of PBSCF-LN cathode remains clean, and its performance degradation due to CO 2 adsorption is recoverable. [ABSTRACT FROM AUTHOR]

Non-aqueous lithium air batteries with high energy density have been regarded to be the most attractive contender in the future energy storage techniques. Herein, the perovskite La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) nanoparticles are studied as the cathode catalyst for non-aqueous lithium air batteries. The results confirm that nanostructured LSCF exhibits admirable electrochemical activity and can effectively reduce the overpotential. Batteries with LSCF catalyst can increase the discharge capacity from 9678 mAh g −1 to 13979 mAh g −1 and improve the cycle stability from 10 cycles to 20 cycles at 200 mA g −1 . The study reveals that the formation and decomposition processes of Li 2 O 2 can be effectively promoted by the introduction of LSCF nanoparticles. The possible catalytic mechanism of LSCF in reducing overpotential is also proposed. [ABSTRACT FROM AUTHOR]

Pd 0.95 Mn 0.05 O-infiltrated (La 0.8 Sr 0.2 ) 0.95 MnO 3−δ –8 mol.% Y 2 O 3 stabilized ZrO 2 (LSM-YSZ) cathode is used to large size (11 × 11 × 0.1 cm) Ni-YSZ anode-supported planar cells for the first time and electrochemically evaluated in the intermediate temperature range from 650 to 800 °C with H 2 as the fuel and air as the oxidant. The initial open circuit voltage (OCV) of the cell is 1.15 V, and the achieved maximum power density increases from 328 to 734 mW cm −2 with the increase of testing temperatures from 600 to 800 °C, which is almost 2.6 times higher than that of the cell with conventional LSM-YSZ cathode. After each thermal cycle between 750 and 300 °C, the OCV remains almost unchanged and the cell voltage decreases less than 0.007 V, indicating that the cell is capable of thermal cycling. The cell voltage at 310 mA cm −2 and 750 °C declines linearly with testing time at a rate of 2.6 × 10 −4 V h −1 for the growth of the infiltrated Pd 0.95 Mn 0.05 O size, resulting in reduction of the total surface area of the particles. The mechanism of performance degradation of the cell with Pd 0.95 Mn 0.05 O-infiltrated LSM-YSZ composites cathode is discussed in detail. [ABSTRACT FROM AUTHOR]

Tubular direct carbon SOFCs (solid oxide fuel cells) supported by YSZ (Y 2 O 3 stabilized ZrO 2 ) electrolyte are fabricated by slurry-casting, slurry-dipping and sintering processes with La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 -10 mol.% Gd 2 O 3 doped CeO 2 (LSCF-10GDC) as the cathode. Their electrochemical performance is examined at temperatures from 700 to 800 °C using molten antimony (Sb) anode and activated carbon fuel. The ohmic resistance of the cell is between 1.01 and 0.37 Ω cm 2 mainly originated from the thick YSZ electrolyte (150 μm); the polarization resistance ranges from 0.22 to 0.06 Ω cm 2 . The maximum power density at 800 °C is 304 mW cm −2 and can be greatly increased by using a thinner and/or more conductive electrolyte. With 1 g activated carbon as the fuel, the cell performance is stable at 200 mW cm −2 at 800 °C for more than 6 h by chemical consumption (oxidization) of the carbon, which reduces the electrochemically formed Sb 2 O 3 to Sb. The cell performance decreases as the fuel is used up and is recovered by refueling. [ABSTRACT FROM AUTHOR]

Ni 0.9 Fe 0.1 -supported solid oxide fuel cells are fabricated by tape casting-screen printing-sintering process; and the activity for CH 4 reforming and electrochemical performance are examined with wet (3 vol.% H 2 O) CH 4 as the fuel at 650 °C, in comparison with Ni-supported cells. At a flow rate of 100 ml min −1 , the wet CH 4 is partially (35 vol.%) reformed to H 2 , CO and CO 2 in the Ni 0.9 Fe 0.1 anode-support, demonstrating a higher reforming activity than that of the Ni anode-support. The maximum power density is 1.01 Wcm −2 at a high limiting current density of 2.6 A cm −2 ; and cell voltage at 0.4 A cm −2 is slightly decreased from 0.65 to 0.60 V within 50 h durability test. This high performance is attributed to the Ni 0.9 Fe 0.1 anode-support that is more active for CH 4 reforming and resistant to carbon deposition than its Ni counterpart. [ABSTRACT FROM AUTHOR]

Metallic Pd and PdO electrodes were prepared by using Pd and PdCl 2 slurries, respectively, and their electrochemical performance as a cathode for oxygen reduction reaction in intermediate temperature solid oxide fuel cells was evaluated by electrochemical impedance spectroscopy (EIS) and direct current polarization (DC polarization). The electrochemical activity of metallic Pd was much higher than that of PdO for the reaction of oxygen reduction; below the decomposition temperature, a thin layer of PdO formed on the surface of metallic Pd electrode, which increased its polarization resistance. The decomposition temperature of PdO decreased from 810 to 750 °C as oxygen partial pressure decreased from 20 to 5 kPa, and was further lowered under the influence of the applied current during DC polarization test. The charge transfer resistance of PdO increased by decreasing oxygen partial pressure, while that of metallic Pd was less sensitive to it. [ABSTRACT FROM AUTHOR]

Abstract: The triiodide ions in the triiodide/iodide redox electrolyte have the disadvantages of corrosion and spectrum absorption, which limits the further application of dye sensitized solar cell (DSSC). In this paper, an iodine-free electrolyte without the addition of iodine into iodide-based electrolyte was developed and the electrochemical performance of this novel electrolyte was evaluated by investigating the influence of iodine concentration on the performance of the electrolytes through UV–vis absorbance spectroscopy, Raman spectrum, current–voltage performance (I–V curve) and electrochemical impedance spectroscopy (EIS) methods. The results indicate that the iodine-free electrolyte could serve as an efficient mediator for DSSC operation. Owing to the absent of the triiodides generated by iodine, the iodine-free electrolyte has low charge recombination and fast electron transport characteristics, leading to relative high open circuit voltage (V oc ). However, acceptable short circuit current (J sc ) was obtained due to the mass transport limitation for iodine-free electrolyte. The results indicate that the iodine-free electrolyte has a potential high performance for DSSC. [Copyright &y& Elsevier]

Abstract: Solution impregnated La0.8Sr0.2Co0.8Ni0.2O3 +Gd-doped CeO2 (LSCN+GDC) cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC) are prepared and their electrochemical properties are evaluated and compared with the conventional LSCN cathodes. The results indicate that the cathode performance can be enhanced by the presence of the nanosized microstructure produced with the solution impregnation method. It is determined that the amount of LSCN loading in the LSCN+GDC composite cathode needs to be higher than 35wt% in order to achieve a performance superior to that of the conventional LSCN cathode. The optimum amount of LSCN loading is in the range of 45–55wt% with an activation energy near 1.32eV for oxygen reduction. At temperatures between 600 and 750°C, the polarization resistance of the 55wt% LSCN loaded LSCN+GDC cathode is in the range of 1.07 and 0.08Ωcm2, which is only about one half of that for the conventional cathode. [Copyright &y& Elsevier]

Abstract: The AB5-type hydrogen storage alloy of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 were synthesized and mixed with PVA (Polyvinyl Alcohol) or different percentage Ni powder as the test samples. The cycle stabilities of the composites were tested in 6M KOH electrolyte through electrochemical method. The results indicated that all the samples with Ni powder have better cycle stabilities and flatter discharge voltage platform. The sample of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 +200wt.% Ni has the highest capacity conservation rate of 80.5% and the longest discharge time of 5.2h. The SEM images show that the particle diameters of the alloy decreased by 2μm and the surface smoothed without sharp edges after adding Ni powder. It can be presumed that adding Ni can improve the cycle stability of the alloy of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 in the alkaline electrolyte and enhance the reaction rate in the charge/discharge cycles. [Copyright &y& Elsevier]