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Spin polarization through a four-quantum-dot system is theoretically studied by considering the effects of Zeeman magnetic field, extrinsic Rashba spin–orbit interaction and external magnetic field. We analyze how the resonance and anti-resonance bands are formed by means of the mathematical formula. By adjusting the external magnetic field, the spin polarization can be converted between −100% and 100%, which suggests a physical scheme of an effective magnetically-controlled spin filter. The combined effect of external magnetic field and extrinsic Rashba spin–orbit interaction leads to spin-polarized oscillations. The introduction of the Zeeman magnetic field makes the system easier to be applied as a spin filter. This study provides theoretical insights into the realization of quantum computing, quantum information transmission and development of nanoscale quantum devices.

Renewable energies from solar and wind power are playing an ever increasing role in meeting the tremendous global energy demand with substantially reduced carbon emissions; however, their intermittent nature poses a critical challenge for sustainability and practical applications. The capability of solid oxide cells (SOCs) to operate in both fuel cell and electrolysis modes makes them one of the most important candidates for efficient storage and regeneration of renewable energies. Here we present a critical review and prospects on the development of key fabrication techniques

Modification is one of the most important and effective methods to improve the photoelectrocatalytic (PEC) performance of ZnO. In this paper, the RuxZn1−xO/Ti electrodes were prepared by thermal decomposition method and the effect of Ru content on those electrodes’ electronic structure was analyzed through the first-principles calculation. Various tests were also performed to observe the microstructures and PEC performance. The results showed that as the Ru4+ transferred into ZnO lattice and replaced a number of Zn2+, the conduction band of ZnO moved downward and the valence band went upward. The number of photogenerated electron-hole pairs increased as the impurity levels appeared in the band gap. In addition, ZnO nanorods exhibited a smaller grain size and a rougher surface under the effect of Ru. Meanwhile, the RuO2 nanoparticles on the surface of ZnO nanorods acted as the electron-transfer channel, helping electrons transfer to the counter electrode and delaying the recombination of the electron-hole pairs. Specifically, the RuxZn1−xO/Ti electrodes with 9.375 mol% Ru exhibited the best PEC performance with a rhodamine B (RhB) removal rate of 97%, much higher than the combination of electrocatalysis (EC, 12%) and photocatalysis (PC, 50%), confirming the synergy of photoelectrocatalysis.

The adsorption and separation of gases are important for mitigating the greenhouse effect, popularizing clean energy and treating volatile organic compounds (VOCs). Metal organic frameworks (MOFs) have been attracted broad attention due to their high specific surface area, adjustable pore structure and surface functionality. MOFs have been widely applied in gas adsorption and separation. The drawbacks of some MOFs are the high humidity sensitivity and poor thermal stability that hinder their industrial applications. Porous carbon materials possess high specific surface area, exceptional chemical and thermal stabilities. Porous carbon materials derived from MOFs as precursors not only overcome the shortcomings of some MOFs with poor water and thermal stabilities, but also retain the advantages of MOFs materials effectively. MOFs-derived porous carbon materials have good application prospects in gas adsorption and separation. This paper introduces the research status of MOFs-derived porous carbon materials, and focuses on their applications in the field of gas adsorption and separation. Synthesis methods for MOFs-derived porous carbon materials mainly include direct carbonization, carbonization with additional precursor and chemical activation. Specific surface area, pore size and surface functional groups of MOFs-derived porous carbon materials have great impact on their adsorption and separation performances for gases (carbon dioxide, hydrogen and volatile organic compounds). In general, MOFs-derived porous carbon materials with high surface area could exhibit excellent adsorption performance for CO2. And the pore size characteristics of MOFs-derived porous carbon materials play important roles in the adsorption capacity and diffusion rate of CO2. Nitrogen doping can improve CO2 adsorption capacities owing to Lewis acid-base interaction, electrostatic interaction and hydrogen bonding between the surface functional groups of MOFs-derived porous carbon materials and CO2. Furthermore, H2 storage is primarily determined by the narrow micropore, and chemical doping can effectively promote H2 storage of MOFs-derived porous carbon materials. In addition, VOCs adsorption is associated with the physiochemical characters of adsorbents (e.g., specific surface area, pore size, pore volume, surface chemical functional groups), properties of adsorbates (e.g., molecular weight, molecular structure, polarity, and boiling point) as well as the adsorption conditions (e.g., temperature and humidity). However, the researches on MOFs-derived porous carbon materials in gas adsorption and separation still face many challenges. (1) The pore structure, morphology and surface chemical properties of MOFs-derived porous carbon materials are directly affected by various factors, such as types of MOFs, types and amounts of additional carbon sources or additional nitrogen sources, carbonization temperature, time and atmosphere, types and ratios of activators, activation temperature and time, chemical doping and so on. (2) There are rare studies on the adsorption mechanism of MOF-derived porous carbon materials for various gases, the multi-component competitive adsorption mechanism, and the influence of environmental factors (such as environmental temperature and humidity) on the adsorption performance. (3) Environmental pollution will be caused during the chemical activation process of MOFs-derived porous carbon materials. At present, there are few reports on the recovery of pyrolysis gases and dispose of the generated waste during the activation process. (4) There is an urgent need to develop new synthetic methods for MOFs-derived porous carbon materials to achieve large-scale production. In a word, the related researches of MOFs-derived porous carbon materials can not only expand the application range of MOFs materials, but also promote the development of gas adsorption and separation. We believe that the application of MOFs-derived porous carbon materials in the field of gas adsorption and separation will make great breakthrough in the future.

Exploring composite materials with ideal structures is an effective way to achieve synergy among different functional components. In this paper, a thermal decomposition method was adopted to prepared IrO2–CeO2-graphene/Ti composite electrodes. The influence of adding graphene on the composite material's electronic structure was analyzed by first-principles calculations, and its microstructure and electrochemical performance were also observed though various tests. The results indicated that coatings containing graphene exhibited a hierarchical porous structure, which could enlarge the specific surface area effectively. The band gaps of the IrO2–CeO2 composite oxides were filled by the energy level of C, which reduced the electron-transfer resistance. With amorphous CeO2 and the graphene acting as highly efficient ion-diffusion and electron-transfer channels respectively, the electrodes' charge storage performances were improved. The electrodes' specific capacitance values rose at first, then decreased as the graphene contents increased, reaching a maximum of 368 F g−1 when the content was 2 mg mL−1. However, adding graphene could harm the electrodes' cycling stability; excessive graphene could also encapsulate IrO2 nanoparticle and hinder contact with the electrolyte, thus reducing the electrodes' specific capacitances.

Electrode/electrolyte interface plays a critical role in the performance and stability of solid oxide fuel cells (SOFCs). In the case of La0·6Sr0·4Co0·2Fe0·8O3-δ (LSCF) cathode, it is well known that cathodic polarization promotes the Sr segregation and diffusion towards the LSCF electrode and Y2O3–ZrO2 (YSZ) electrolyte interface, leading to the formation of SrZrO3 secondary phase and the disintegration of LSCF structure at the interface. On the other hand, LSCF is chemically stable with doped ceria electrolytes such as Gd-doped CeO2 (GDC). However, there appears no comparative studies on the intrinsic relationship between the surface segregation, interface reaction and stability of LSCF in YSZ and GDC electrolytes. Here, a comparative study has been carried out on the segregation and interface formation of LSCF on GDC and YSZ electrolyte under identical cathodic polarization conditions at 750 °C and 1000 mAcm−2 using focused ion beam and scanning transmission electron microscopy (FIB-STEM) techniques. Segregation of Sr occurs in the LSCF-GDC system, however, the inertness of GDC electrolyte suppresses the segregation process of Sr species. Instead, surface segregation of B-site Co cation becomes dominant under the cathodic polarization, forming isolated CoOx particles. The results indicate that the existence of chemical catchers such as Zr in the case of YSZ electrolyte for the segregated Sr species is kinetically the driving force for the Sr segregation and stability of LSCF electrodes under SOFC operation conditions.

Solid oxide cells (SOCs) are highly efficient and environmentally benign devices that can be used to store renewable electrical energy in the form of fuels such as hydrogen in the solid oxide electrolysis cell mode and regenerate electrical power using stored fuels in the solid oxide fuel cell mode. Despite this, insufficient long-term durability over 5–10 years in terms of lifespan remains a critical issue in the development of reliable SOC technologies in which the surface segregation of cations, particularly strontium (Sr) on oxygen electrodes, plays a critical role in the surface chemistry of oxygen electrodes and is integral to the overall performance and durability of SOCs. Due to this, this review will provide a critical overview of the surface segregation phenomenon, including influential factors, driving forces, reactivity with volatile impurities such as chromium, boron, sulphur and carbon dioxide, interactions at electrode/electrolyte interfaces and influences on the electrochemical performance and stability of SOCs with an emphasis on Sr segregation in widely investigated (La,Sr)MnO3and (La,Sr)(Co,Fe)O3−δ. In addition, this review will present strategies for the mitigation of Sr surface segregation.Graphic Abstract

Antiresonance and its application in triple-quantum-dot systems are studied theoretically using nonequilibrium Green’s function method. The presence or absence of antiresonance point can be used to determine whether quantum dot impurity exists in the system. For a tri-quantum-dot ring, the conversion between 0 and 1 for the conductance can be realized by adjusting the energy levels of quantum dots, which makes the system applicable as a quantum switch. The coupling strength can be measured according to the energy level of the antiresonance point. Once the intradot Coulomb interactions are taken into account, three new Fano antiresonances emerge in the conductance spectrum. Under the action of the magnetic field, two antiresonance points disappear simultaneously. Our work sheds lights onto the design and implementation of new quantum functional devices for electronic measurements.

Glass and glass-ceramic are one of the key sealing materials for solid oxide fuel cells (SOFCs) and they need to meet stringent requirements for long-term operation at high temperatures. Here, we report for the first time the incorporation of aluminum nitride (AlN) dopant into borosilicate glasses and glass-ceramics so as to tailor their basic properties and sealing performance. The results show the AlN-doped glass-ceramics exhibit remarkably enhanced thermal stability and chemical compatibility when adhering to Y2O3-ZrO2 electrolyte. The electrical conductivity is also significantly reduced by the AlN doping, and the conductivity of 15 wt.% AlN-doped glass-ceramic is nearly two orders of magnitude lower than that of the undoped glass-ceramic. This work indicates that AlN doping is an effective strategy to obtain a reliable borosilicate glass-ceramics for SOFCs.

Compounding different materials to be the electrode is a good way in the field of supercapacitors. IrO2 was used as an active and conductor oxide, and ZnO was used as a semiconductor oxide. Carbon nanotube (CNT) and Graphene (G) were used to prepare the electrodes of IrO2-ZnO-carbon nanotube (CNT)/Ti and IrO2-ZnO-graphene oxide (G)/Ti by thermal decomposition method and their different effect on the properties was studied in detail. The surface of IrO2-ZnO-CNT/Ti had a "hill-bag" structure, and the IrO2-ZnO-G/Ti had a graphene sheet layered fold structure, their specific surface area and pore volume were significantly greater than that of an electrode without carbon material. The specific capacitances of IrO2-ZnO-G/Ti and IrO2-ZnO-CNT/Ti were 681 F g-1 and 501F g-1, respectively, which were higher than IrO2-ZnO/Ti (399 F g-1). The capacitance retention rate of the IrO2-ZnO-G/Ti electrode coating was 80.24% after 20,000 cyclic tests, which was worse than that of IrO2-ZnO/Ti (90.65%). The addition of carbon materials reduced the cycle stability, but the binding effect of graphene and the coating was better than that of carbon nanotubes. Graphene improved the overall performance better than that of carbon nanotubes. A binder-free asymmetric supercapacitor working in H2SO4 solution was assembled with RuO2-MoO3/Ti and IrO2-ZnO-G/Ti as cathodic and anodic electrode respectively. It exhibited the energy densities of 29.6 W h kg-1 and 25.3 W h kg-1 when the power density was 700 W kg-1 and 3505 W kg-1 respectively. The preliminary charge/discharge mechanism of the asymmetric supercapacitor in the H2SO4 solution was presented.

Combined chromium and sulfur poisoning for La0.8Sr0.2MnO3-δ (LSM) cathodes of solid oxide fuel cells (SOFCs) were investigated with cathodic current of 200 mA cm−2 under 800 °C for 22 h. After polarization in chromium and sulfur at 800 °C for 22 h, polarization and ohmic resistance for LSM electrodes were 5.1 Ω cm2 and 7.62 Ω cm2, which were larger than values of LSM electrodes after chromium deposition only and sulfur deposition only. EDS, XPS and XRD results showed chromium and sulfur deposition occurred especially in bulk of the electrode, forming SrCrO4 and SrSO4. Compared with chromium deposition only, sulfur deposition only, combined chromium and sulfur deposition was not random and the degradation phenomenon of chromium and sulfur poisoning was much more severe. The combined chromium and sulfur deposition of LSM electrodes was induced by interaction among CrO, SO2 and segregated SrO from LSM electrode. Thermodynamic predictions have been carried out utilizing CALPHAD approach, which were found in agreement with observed experimental results.

A novel molten salt method was employed to synthesize 10% Nb doped La0.6Sr0.4FeO3−δ (LSFN). The as-synthesized powders were pure and adopted a porous structure. Using LSFN as the oxygen electrode for a reversible solid oxide cell, the button cell exhibited a peak power density of 0.79 W cm−2 in H2 and an electrolysis current density of 0.89 A cm−2 at 1.3 V in 50% CO2/50% H2 at 800 °C. A large fraction of Fe2+ was found in LSFN, resulting in the improved performance. Our results indicate that the molten salt method is a promising approach for the synthesis of highly active perovskite electrode with a dopant of Nb.

A novel high-performance epoxy resin diphenyldi (9,9-Di-(4-(2,3-epoxypropoxy) phenyl)-4,5-diazafluorenoxysilane) (DEPFS) containing the diazafluorene and silicon group was synthesized by the nucleophilic substitution for the first time and added to bisphenol A epoxy resin (E-51) to form a thermoset blend. We observed that the incorporation of DEPFS remarkably enhanced the flame retardancy and thermal properties of E-51. The cured E-51-30% DEPFS thermoset exhibited a glass transition temperature of 187 °C and a limiting oxygen index of 30.1%, much higher than 153 °C and 22.6% for those of pristine E-51 thermoset, respectively. In addition, the incorporation of DEPFS has dual enhancement effects on the toughness and tensile strength of E-51. This study provides an effective means to prepare a high-performance epoxy resins and proposes flame retardancy and simultaneous reinforcing and toughening mechanism. It was found that the DEPFS with diverse performance has allowed an increasing number of versatile industrial application such as microelectronics, electronics, aerospace and so on.

The high volatility of boron from borosilicate glass sealants often leads to boron deposition and poisoning of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) cathode, presenting a challenge for the development of reliable solid oxide fuel cells (SOFCs). In this paper, we report that boron volatilization from borosilicate glass at 700 °C can be significantly suppressed by appropriate NiO dopant, mainly due to the increase of Si-O-B linkages in the combining B-O− and Si-O− network. Also, the formation of boron-containing phase in NiO-doping glass-ceramics has been studied, which suppresses the reaction between glass and LSCF cathode after heat treatment at 700 °C for 1000 h. Moreover, the change of crystalline phases leads to an improvement in thermal and electrical properties. We believe that our findings will open a new way for the design and development of the reliable sealing glass for SOFCs applications.

Crack formation at the interface between sealing glass and other cell components is one of the key issues in constraining the development of solid oxide fuel cells (SOFCs). Herein, we report our finding on tuning the mechanical and thermal properties of borosilicate glass by doping Nb2O5. We observe the formation of Ba3Nb10O28 crystalline phase in the Nb2O5-doped glass, leading to significantly enhanced crack-resistant and self-healing abilities of the glass. In addition, we demonstrate long-term thermal and chemical stability at the sealing interface between the Nb2O5-doped glass-ceramics and Y2O3-ZrO2 electrolyte after heat-treatment at 700 °C for 1000 h. The possible mechanism for the improved crack-resistant and self-healing properties is discussed.

Employing the nonequilibrium Green’s function technique, electron transport characteristics through a laterally coupled triple-quantum-dot chain are investigated. The conductance versus electron energy is numerically calculated. Two anti-resonance points change into two anti-resonance bands with increasing the size of triple-quantum-dot chain. The widths of two anti-resonance bands are the same and can be regulated via adjusting the inter-dot tunneling coupling strength in the main chain or its attachment. Spin-polarized window emerges due to Zeeman splitting as an external magnetic flux is introduced. Our studies demonstrate that the system can be used as a quantum switch or an efficient spin filtering.

Layered Ruddlesden-Popper La2NiO4+δ (LNO) is reported to possess excellent oxygen surface and bulk transport properties, but its application as the cathode of solid oxide fuel cells is restrained by the relatively poor electrocatalytic activity. Here, we report the incorporation of highly ion-conducting Er-stabilized Bi2O3 (ESB) into LNO and assemble the LNO-ESB composite cathode directly on zirconia electrolyte film using a facile electrochemical polarization approach. The results show the presence of ESB remarkably reduces the contact resistance at the electrode/electrolyte interface and enhances the electrocatalytic activity and cation stability of LNO. The cell with the LNO-ESB cathode generates a peak power density of 852 mW cm-2 at 750°C with reasonable operating stability over 200 h. This work demonstrates the feasibility of incorporating ESB to promote the layered nickelate cathodes for intermediate temperature solid oxide fuel cells. Published version

Bismuth-based oxides exhibit outstanding oxygen ionic conductivity and fast oxygen surface kinetics and have shown great potential as a highly active component for electrode materials in solid oxide fuel cells (SOFCs). Herein, a Nb-doped La0.6Sr0.4Co0.2Fe0.7Nb0.1O3-δ (LSCFNb) electrode with 40% Er0.4Bi1.6O3 (ESB) composite electrode was successfully fabricated by decoration method and directly assembled on barrier-layer-free yttrium-stabilized zirconia (YSZ) electrolyte cells, achieving a peak power density of 1.32 W cm-2 and excellent stability at 750 °C and 250 mA cm-2 for 100 h. ESB decoration also significantly reduces the activation energy from 214 kJ mol-1 for the O2 reduction on pristine LSCFNb electrode to 98 kJ mol-1. Further microstructural analysis reveals that there is a redistribution and migration of the ESB phase in the ESB-LSCFNb composite toward the YSZ electrolyte under the influence of cathodic polarization, forming a thin ESB layer at the cathode/YSZ electrolyte interface. The in situ formed ESB layer not only prevents the direct contact and subsequent reaction between segregated SrO and YSZ electrolytes, but also remarkably promotes the oxygen migration/diffusion at the interface for O2 reduction reaction, resulting in a remarkable increase in power output and a decrease in activation energy. The present study clearly demonstrated the in situ formation of a highly functional and active ESB protective layer at LSCFNb cobaltite cathode and YSZ electrolyte interface via ESB-decorated LSCFNb composite cathode under SOFC operation conditions.

Phosphate glass is advantageous as a low temperature sealing material, especially in solar cells, micro-motor systems, vacuum engineering and the like, but the poor chemical stability restricts its wide application, especially in humid environments. To overcome this shortcoming, a certain proportion of silicon nitride is added to tailor the structural, chemical and thermal properties of phosphate glass. The results show that the addition of silicon nitride improves the water resistance and remarkably reduces the mass loss in humid environments from 60 to 3 wt% after 120 h. With the addition of silicon nitride, the softening temperature of glass is in the range of 330–372 °C. In particular, the coefficient of thermal expansion of phosphate glass can be tailored ranging from 14.9 × 10−6 K−1 to 17.4 × 10−6 K−1 by adjusting the content of silicon nitride, making it thermally compatible with various substrates. These findings provide useful information on the development of reliable low-temperature sealing glass.

This work was financially supported by the Australian Research Council under the Discovery Project Scheme (project numbers: DP180100731 and DP180100568), and by the Guangdong Provincial Department of Science and Technology Agency (GDST) under the GDST-NOW Science-Industry Cooperation Program (No. 2017A050501053). The establishment of intimate electrode/electrolyte interface is very important in solid oxide fuel cells (SOFCs), because it plays a critical role in the overall cell performance and durability. In this study, Mn segregation and interface formation between directly assembled La0.8Sr0.2MnO3 (LSM) electrode and yttrium-stabilized zirconia (YSZ) or gadolinium-doped ceria (GDC) electrolytes are studied using combined focused ion beam and scanning transmission electron microscopy (FIB-STEM). In the case of LSM/YSZ and LSM/GDC electrodes, a significant reduction in the electrode ohmic resistance is observed after cathodic polarization at 900 °C and 500 mA cm−2, indicating the formation of an intimate interface. However, LSM particles start to disintegrate at the electrode/electrolyte interface with the increase of polarization time in the case of LSM/YSZ electrode. On the other hand, the LSM/GDC interface is very stable with negligible microstructure change at the interface. Mn segregation from the LSM perovskite structure is identified under the influence of polarization in both LSM/YSZ and LSM/GDC electrodes. The results demonstrate that nature of the electrolyte plays a critical role in the electrochemical activity, microstructure, morphology and stability of LSM/electrolyte interface under SOFC operation conditions. Postprint

The rigid nature of sealing glass-ceramics restricts the thermal cycling stability of Solid Oxide Fuel Cells (SOFCs), which thus evokes an interest in designing a sealing glass without crystallization under the operational condition of SOFCs. In this paper, we report that the sealing performance of 30Na2O-70SiO2 (in mole%) glass-ceramic can be significantly improved by Fe2O3 dopant through a composite approach. In particular, the crystallization in glass can be suppressed by appropriate Fe2O3 dopant amount (8 mol%), which results in the improved sealing property of glass. In addition, the glass modified with Fe2O3 shows good chemical compatibility with 8 mol% yttria-stabilized zirconia (8YSZ) electrolyte and metallic interconnect (430 stainless steel) in dual atmospheres. The possible mechanism for the improved sealing performance of 30Na2O-70SiO2 glass-ceramic by this unique composite approach is also discussed.

Modification is one of the most important and effective methods to improve the photoelectrocatalytic (PEC) performance of ZnO. In this paper, the RuxZn1-xO/Ti electrodes were prepared by thermal decomposition method and the effect of Ru content on those electrodes’ electronic structure was analyzed through the first-principles calculation. Various tests were also performed to observe the microstructures and PEC performance. The results showed that as the Ru4+ transferred into ZnO lattice and replaced a number of Zn2+, the conduction band of ZnO moved downward and the valence band went upward. The number of photogenerated electron-hole pairs increased as the impurity levels appeared in the band gap. In addition, ZnO nanorods exhibited a smaller grain size and a rougher surface under the effect of Ru. Meanwhile, the RuO2 nanoparticles on the surface of ZnO nanorods acted as the electron-transfer channel, helping electrons transfer to the counter electrode and delaying the recombination of the electron-hole pairs. Specifically, the RuxZn1-xO/Ti electrodes with 9.375mol% Ru exhibited the best PEC performance with a rhodamine B (RhB) removal rate of 97%, much higher than the combination of simple electrocatalysis (EC 12%) and photocatalysis (PC 50%), confirming the synergy of photoelectrocatalysis.

In this study, pyrochlore Pr2B2O7 oxides (B Zr, ZrSn, Sn, PZO/PZSO/PSO) and perovskite (B Ti, PTO) were prepared as direct ammonia solid oxide fuel cell (DA-SOFC) cathode with oxygen reduction reaction activity induced by B-site cationic defects. Compared with PTO, the pyrochlore PBO with unoccupied 8a-oxygen sites are high in inherent oxygen vacancies (ca. 12.5%), leading to enhanced migration of lattice oxygen. Among the n-type semiconductors, PZO is with a more negative flat-band potential and is more effective in terms of overcoming energy barriers. As a result, the conductivity of PZO is two orders of magnitude higher than that of PTO at 800 °C. The oxygen transport performance reveals that the surface exchange coefficient of PZO is about one order of magnitude higher than that of La0.7Sr0.3MnO3-δ at 900 °C. Owing to high conductivity, fast oxygen transport, and matched thermal expansion coefficient, an anode-supported DA-SOFC using the PZO-based cathode can offer a maximum power density of 0.25 W cm−2 at 600 °C and 1.22 W cm−2 at 800 °C, operating continuously over 100 h without obvious degradation. The electrochemical performance is 2.3 folds higher than those of SOFCs using other PBO-based cathode, and higher than most reported SOFCs with the cathodes using A-site Pr.

Making full use of low-energy photons and reducing photogenerated carriers' recombination rate have been considered important ways to raise photoelectrocatalysis (PEC) efficiency. In this study, Ir-doped ZnO PEC electrodes were prepared by thermal decomposition method, first principles calculations were used to study the effects of Ir content on the electronic structure and optical properties of Ir

Bismuth oxide is as an active promoter in enhancing the ionic conductivity and electrocatalytic activity of manganite oxygen electrodes of solid oxide cells, but there are very limited reports on the formation and evolution of electrode/electrolyte interface of bismuth oxide-manganite composite electrode under the influence of electrochemical polarization. Herein, we report the effect of electrochemical polarization and direction of polarization current on the electrocatalytic performance and electrode/electrolyte interface of a (La0·8Sr0.2)0.95Mn0·95Pt0·05O3+δ-Er0.4Bi1·6O3 (LSMPt-ESB) composite oxygen electrode assembled on zirconia electrolyte. The cell with the LSMPt-ESB electrode produces outstanding performance for power generation and steam splitting, and it is stable without noticeable degradation during operation at 600 °C for 350 h in the fuel cell mode. The cathodic polarization induces in operando formation of electrode/electrolyte interface with observation of an Er-deficient LSMPt-ESB dense layer and Er-rich (Er,Bi,Mn)Ox particles on the zirconia electrolyte surface. This is different to the case of dwell under open circuit and in particular under anodic polarization conditions. The present study gains insights into the development of high performance, reliable bismuth oxide-manganite composite oxygen electrode for reduced temperature solid oxide cells.

We theoretically study the average current through a ring embedded with multiple quantum dots in each arm subjected to a time-dependent external field. A current resonance band can be observed in a six-quantum-dot system. In the presence of a time-dependent external field, mutual transformation occurs between the resonance band and antiresonance band, indicating an effective optically-controlled quantum switch can be realized in a wider quantum dot’s energy regime. As the Zeeman effect is introduced, the conversion between 100 and − 100% for spin polarization $$p$$ p can be realized by adjusting the frequency of time-dependent external field, suggesting a physical scheme of an optically-controlled spin filter. The present work sheds lights onto the design and quantum computation of future nano-devices.

Cellular metals with a large surface-to-volume ratio and excellent electrical conductivity have attracted great attention due to their wide application. However, the existing processes for fabrication of cellular metallic structures are generally complex and dependent on the sacrificial materials or templates, and therefore, it is highly desirable to develop a facile process. Herein, we propose a novel gas-assisted reconstruction strategy for in situ fabrication of micron-porous architectures on Ag precursor metal using a CH4/O2 gas mixture at 750 °C. The obtained results indicate that large-area and clean, porous Ag architectures are successfully created through the treatment in CH4/O2 gas. The formation of cellular structure is mainly due to the simultaneous diffusion of H2, CO and O2 into Ag bulk and fast reaction at elevated temperatures. The process is clean and applicable to creation of porous architectures (from surface texturing to 3-D cellular structure) on Ag metal, avoiding the use of sacrificial materials or templates. Furthermore, we have demonstrated that the formed micron-porous Ag sheet with large effective area, high electrical conductivity can be directly used as a free-standing electrode for electrochemical supercapacitors with a high capacitance.

At present, the insufficient thermo-mechanical stability of sealing glass presents a challenge for solid oxide fuel cells (SOFCs). In this work, we report for the first time that a rigid-resilient transition occurs in a calcium borosilicate sealing glass upon heating at 700 °C for different durations. The elastic modulus increases from 28.1–40.0 GPa for 24 h to 92.3–105.1 GPa for 100 h, while the corresponding hardness increases from 2.5–3.1 GPa to 8.1–9.2 GPa. In addition, a possible mechanism for the rigid-resilient transition has been proposed. The reported results provide a new approach to solve the sealing problem of SOFCs.