• Energy Research

By harnessing dynamic MOF nanosheets, zinc anodes underwent a remarkable self-optimization process, resulting in the creation of a highly desirable surface with an unprecedented (002) orientation that is entirely free from any undesirable byproducts.

A new Ni-BaCe0.4Zr0.4Nd0.2O3-δ （Ni-BZCN4）cermet membrane was used to separate hydrogen from mixed gas containing hydrogen. Hydrogen permeation properties of the membrane were investigated under various conditions. Hydrogen permeation flux increases with temperature. When the feed gas was moistened by 3% H2O, the flux is about twice of that not moistened. And it reaches 0.29 cm3/ min.cm2 at 900 °C when a wet 80% H2/He feed gas was used. The permeation stability of Ni-BaCe0.4Zr0.4Nd0.2O3-δ membrane was investigated under atmospheres containing 30% CO2 and H2O. After 100 h operation, the membrane still keeps a steady permeation flux. These results suggest that the Ni-BZCN4 membrane is suitable for hydrogen separation from mixed gas containing H2 and CO2.

SrCo(0.8)Fe(0.2)O(3-δ) is a controversial material whether it is used as an oxygen permeable membrane or as a cathode of solid oxide fuel cells. In this paper, carefully synthesized powders of perovskite-type Sr(x)Co(0.8)Fe(0.2)O(3-δ) (x = 0.80-1.20) oxides are utilized to investigate the effect of A-site nonstoichiometry on their electrochemical performance. The electrical conductivity, sintering property and stability in ambient air of Sr(x)Co(0.8)Fe(0.2)O(3-δ) are critically dependent on the A-site nonstoichiometry. Sr(1.00)Co(0.8)Fe(0.2)O(3-δ) has a single-phase cubic perovskite structure, but a cobalt-iron oxide impurity appears in A-site cation deficient samples and Sr(3)(Co, Fe)(2)O(7-δ) appears when there is an A-site cation excess. It was found that the presence of the cobalt-iron oxide improves the electrochemical performance. However, Sr(3)(Co, Fe)(2)O(7-δ) has a significant negative influence on the electrochemical activity for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The peak power densities with a single-layer Sr(1.00)Co(0.8)Fe(0.2)O(3-δ) cathode are 275, 475, 749 and 962 mW cm(-2) at 550, 600, 650 and 700 °C, respectively, values which are slightly lower than those for Sr(0.95)Co(0.8)Fe(0.2)O(3-δ) (e.g. 1025 mW cm(-2) at 700 °C) but much higher than those for Sr(1.05)Co(0.8)Fe(0.2)O(3-δ) (e.g. only 371 mW cm(-2) at 700 °C). This remarkable dependence of electrochemical performance of the Sr(x)Co(0.8)Fe(0.2)O(3-δ) cathode on the A-site nonstoichiometry reveals that lower values of electrochemical activity reported in the literature may be induced by an A-site cation excess. Therefore, to obtain a high performance of Sr(x)Co(0.8)Fe(0.2)O(3-δ) cathode for IT-SOFCs, an A-site cation excess must be avoided.

A pioneering achievement is made in developing integrated Janus hydrogel electrolytes featuring gradient pores in cross-section and varying hydrophilicities on surfaces. This novel hydrogel enables Zn-ion batteries to exhibit excellent performance.

We propose a new method for hydrogen separation using an oxygen-permeable ceramic membrane, and achieve a high hydrogen separation rate comparable to those of Pd-based membranes and excellent stability under a H2S-containing atmosphere.

Thin proton-conducting electrolyte with composition BaCe0.8Gd0.2O3-delta (BCGO) was prepared over substrates composed of Ce0.8Gd0.2O1.9 (CGO)-Ni by the dry-pressing method. Solid oxide fuel cells (SOFCs) were fabricated with the structure Ni-CGO/BCGO/Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCFO)-CGO. The performance of a single cell was tested at 600 and 650 degrees C, with ammonia directly used as fuel. The open circuit voltages (OCVs) were 1.12 and 1.1 V at 600 and 650 degrees C, respectively. The higher OCV may be due to both the compaction of the BCGO electrolyte (no porosity) and complete decomposition of ammonia. The maximum power density was 147 mW cm(-2) at 600 degrees C. Comparisons of the cell with hydrogen as fuel indicate that ammonia can be treated as a substitute liquid fuel for SOFCs based on a proton-conducting solid electrolyte. (c) 2007 Elsevier B.V. All rights reserved.

Abstract The chemical compatibility of the Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) with the yttria-stabilized zirconia (YSZ) electrolyte or Gd-doped ceria electrolyte (GDC), as well as that of the GDC with the YSZ electrolyte were examined. It was found that BSCF had a good compatibility with the GDC electrolyte but a poor chemical compatibility with the YSZ electrolyte. The BSCF cathode was adopted for anode-supported YSZ electrolyte cells with and without the application of a 1 μm thick GDC buffering layer between the cathode and the YSZ electrolyte. The interfacial reactions of the BSCF with the YSZ electrolyte surface and the GDC coated YSZ surfaces were investigated. The single cells were evaluated by using I–V curve measurements and AC impedance spectroscopy. The results depicted a great improvement in cell performance and a significant decrease in polarization resistance after adding the GDC buffer layer. The optimum firing temperature of the GDC film onto the YSZ film was around 1250 °C, which led to the maximum power density of 1.56 W cm−2 at 800 °C using air as oxidant and hydrogen as fuel.