Multilayered Ceramic Membrane with Ion Conducting Thin Layer Induced by Interface Reaction for Stable Hydrogen Production.

Conventional methods for fabricating multilayered ceramic membranes with ion conducting dense thin layers are often cumbersome, costly, and limited by poor adhesion between layers. Inspired by the architectural structure of the rooted grasses in soil, here, we report an interface-reaction-induced reassembly approach for the direct fabrication of Ce0.9 Gd0.1 O2-δ (CGO) thin layers rooted in the parent multilayered ceramic membranes by only one firing step. The CGO dense layers are very thin, and adhered strongly to the parent support layer, ensuring low ionic transport resistance and structural integrity of the multilayered membranes. When using as an oxygen permeable membrane for upgrading fossil-fuel-derived hydrogen, it shows very long durability in harsh conditions containing H2 O, CH4 , H2 , CO2 and H2 S. Furthermore, our approach is highly scalable and applicable to a wide variety of ion conducting thin layers, including Y0.08 Zr0.92 O2-δ , Ce0.9 Sm0.1 O2-δ and Ce0.9 Pr0.1 O2-δ .

Hydrogen Purification through a Highly Stable Dual-Phase Oxygen-Permeable Membrane.

Using oxygen permeable membranes (OPMs) to upgrade low-purity hydrogen is a promising concept for high-purity H2 production. At high temperatures, water dissociates into hydrogen and oxygen. The oxygen permeates through OPM and oxidizes hydrogen in a waste stream on the other side of the membrane. Pure hydrogen can be obtained on the water-splitting side after condensation. However, the existing Co- and Fe-based OPMs are chemically instable as a result of the over-reduction of Co and Fe ions under reducing atmospheres. Herein, a dual-phase membrane Ce0.9 Pr0.1 O2-δ -Pr0.1 Sr0.9 Mg0.1 Ti0.9 O3-δ (CPO-PSM-Ti) with excellent chemical stability and mixed oxygen ionic-electronic conductivity under reducing atmospheres was developed for H2 purification. An acceptable H2 production rate of 0.52 mL min-1 cm-2 is achieved at 940 °C. No obvious degradation during 180 h of operation indicates the robust stability of CPO-PSM-Ti membrane. The proven mixed conductivity and excellent stability of CPO-PSM-Ti give prospective advantages over existing OPMs for upgrading low-purity hydrogen.

Improved Energy Density at High Temperatures of FPE Dielectrics by Extreme Low Loading of CQDs.

Electrostatic capacitors, with the advantages of high-power density, fast charging-discharging, and outstanding cyclic stability, have become important energy storage devices for modern power electronics. However, the insulation performance of the dielectrics in capacitors will significantly deteriorate under the conditions of high temperatures and electric fields, resulting in limited capacitive performance. In this paper, we report a method to improve the high-temperature energy storage performance of a polymer dielectric for capacitors by incorporating an extremely low loading of 0.5 wt% carbon quantum dots (CQDs) into a fluorene polyester (FPE) polymer. CQDs possess a high electron affinity energy, enabling them to capture migrating carriers and exhibit a unique Coulomb-blocking effect to scatter electrons, thereby restricting electron migration. As a result, the breakdown strength and energy storage properties of the CQD/FPE nanocomposites are significantly enhanced. For instance, the energy density of 0.5 wt% CQD/FPE nanocomposites at room temperature, with an efficiency (η) exceeding 90%, reached 9.6 J/cm3. At the discharge energy density of 0.5 wt%, the CQD/FPE nanocomposites remained at 4.53 J/cm3 with an efficiency (η) exceeding 90% at 150 °C, which surpasses lots of reported results.

Progress on Polymer Dielectrics for Electrostatic Capacitors Application.

Polymer dielectrics are attracting increasing attention for electrical energy storage owing to their advantages of mechanical flexibility, corrosion resistance, facile processability, light weight, great reliability, and high operating voltages. However, the dielectric constants of most dielectric polymers are less than 10, which results in low energy densities and limits their applications in electrostatic capacitors for advanced electronics and electrical power systems. Therefore, intensive efforts have been placed on the development of high-energy-density polymer dielectrics. In this perspective, the most recent results on the all-organic polymer dielectrics are summarized, including molecular structure design, polymer blends, and layered structured polymers. The challenges in the field and suggestions for future research on high-energy-density polymer dielectrics are also presented.

Chemical Environment-Induced Mixed Conductivity of Titanate as a Highly Stable Oxygen Transport Membrane.

Coupling of two oxygen-involved reactions at the opposite sides of an oxygen transport membrane (OTM) has demonstrated great potential for process intensification. However, the current cobalt- or iron-containing OTMs suffer from poor reduction tolerance, which are incompetent for membrane reactor working in low oxygen partial pressure (pO2). Here, we report for the first time a both Co- and Fe-free SrMg0.15Zr0.05Ti0.8O3-δ (SMZ-Ti) membrane that exhibits both superior reduction tolerance for 100 h in 20 vol.% H2/Ar and environment-induced mixed conductivity due to the modest reduction of Ti4+ to Ti3+ in low pO2. We further demonstrate that SMZ-Ti is ideally suited for membrane reactor where water splitting is coupled with methane reforming at the opposite sides to simultaneously obtain hydrogen and synthesis gas. These results extend the scope of mixed conducting materials to include titanates and open up new avenues for the design of chemically stable membrane materials for high-performance membrane reactors.

Enhanced durability and activity of the perovskite electrocatalyst Pr0.5Ba0.5CoO3-δ by Ca doping for the oxygen evolution reaction at room temperature.

A promising Ca doping approach was reported to improve the durability and electrocatalytic OER activity of the perovskite Pr0.5Ba0.5CoO3-δ (PBC). Compared to the pristine PBC, the electrocatalytic activity of Ca-doped Pr0.5Ba0.3Ca0.2CoO3-δ perovskite was increased by ca. 90%. More importantly, its durability was significantly enhanced after doping with calcium.