Dielectric Properties Bi₂MgTaNbO₉

A phase-pure mixed oxide of the composition Bi2MgNbTaO9 with a pyrochlore structure was obtained by the ceramic synthesis method. The sample was characterized by the methods of X-ray phase and EDS analyzes, electron scanning microscopy. The electrical properties of samples of different thicknesses were investigated by impedance spectroscopy. The unit cell parameter is a = 1.0544 nm (sp. gr. Fd3m). As a result of modeling the impedance hodographs, an equivalent circuit is proposed that satisfactorily describes the electrical behavior of the sample. Bi2MgNbTaO9 is characterized by a high activation energy of 1.28 eV; moderately high dielectric constant ~62–71 and dielectric loss tangent ~0.003 at 1 MHz and 18 °С. No ionic transfer was detected. The investigated ceramics can be used to create multilayer ceramic capacitors

Electrochemical performance of La2NiO4+δ-Ce0.55La0.45O2−δ as a promising bifunctional oxygen electrode for reversible solid oxide cells

In this work, La2NiO4+δ-xCe0.55La0.45O2−δ (denoted as LNO-xLDC) with various LDC contents (x = 0, 10, 20, 30, and 40 wt%) were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells (RSOCs). Compared with the pure LNO, the optimum composition of LNO-30LDC exhibited the lowest polarization resistance (Rp) of 0.53 and 0.12 Ω·cm2 in air at 650 and 750 °C, respectively. The enhanced electrochemical performance of LNO-30LDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer channels. The hydrogen electrode supported single cell with LNO-30LDC oxygen electrode displayed peak power densities of 276, 401, and 521 mW·cm−2 at 700, 750, and 800 °C, respectively. Moreover, the electrolysis current density of the single cell demonstrated 526.39 mA·cm−2 under 1.5 V at 800 °C, and the corresponding hydrogen production rate was 220.03 mL·cm−2·h−1. The encouraging results indicated that LNO-30LDC was a promising bifunctional oxygen electrode material for RSOCs.

Electrochemical p erformance of La2NiO4+δ-Ce0.55La0.45O2-δ as a promising bifunctional oxygen electrode for reversible solid oxide cells

In this work, La2NiO4+δ-xCe0.55La0.45O2-δ (denoted as LNO-xLDC) with various LDC contents (x = 0, 10, 20, 30 and 40, wt %) were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells (RSOCs). Compared with the pure LNO, the optimum composition of LNO-30LDC exhibited the lowest polarization resistance (Rp) of 0.53 and 0.12 Ω·cm2 in air at 650 and 750 oC, respectively. The enhanced electrochemical performance of LNO-30LDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer channels. The hydrogen electrode supported single cell with LNO-30LDC oxygen electrode displayed peak power densities of 276, 401 and 521 mW·cm-2 at 700, 750 and 800 oC, respectively. Moreover, the electrolysis current density of the single cell demonstrated 526.39 mA·cm-2 under 1.5 V at 800 oC, and the corresponding hydrogen production rate was 220.03 ml·cm-2·h-1. The encouraging results indicated that LNO-30LDC was a promising bifunctional oxygen electrode material for RSOCs.

Advanced Anode Materials of Potassium Ion Batteries: from Zero Dimension to Three Dimensions

Potassium ion batteries (PIBs) with the prominent advantages of sufficient reserves and economical cost are attractive candidates of new rechargeable batteries for large-grid electrochemical energy storage systems (EESs). However, there are still some obstacles like large size of K+ to commercial PIBs applications. Therefore, rational structural design based on appropriate materials is essential to obtain practical PIBs anode with K+ accommodated and fast diffused. Nanostructural design has been considered as one of the effective strategies to solve these issues owing to unique physicochemical properties. Accordingly, quite a few recent anode materials with different dimensions in PIBs have been reported, mainly involving in carbon materials, metal-based chalcogenides (MCs), metal-based oxides (MOs), and alloying materials. Among these anodes, nanostructural carbon materials with shorter ionic transfer path are beneficial for decreasing the resistances of transportation. Besides, MCs, MOs, and alloying materials with nanostructures can effectively alleviate their stress changes. Herein, these materials are classified into 0D, 1D, 2D, and 3D. Particularly, the relationship between different dimensional structures and the corresponding electrochemical performances has been outlined. Meanwhile, some strategies are proposed to deal with the current disadvantages. Hope that the readers are enlightened from this review to carry out further experiments better.

Superionic Conductivity in Ceria-Based Heterostructure Composites for Low-Temperature Solid Oxide Fuel Cells

Ceria-based heterostructure composite (CHC) has become a new stream to develop advanced low-temperature (300–600 °C) solid oxide fuel cells (LTSOFCs) with excellent power outputs at 1000 mW cm−2 level. The state-of-the-art ceria–carbonate or ceria–semiconductor heterostructure composites have made the CHC systems significantly contribute to both fundamental and applied science researches of LTSOFCs; however, a deep scientific understanding to achieve excellent fuel cell performance and high superionic conduction is still missing, which may hinder its wide application and commercialization. This review aims to establish a new fundamental strategy for superionic conduction of the CHC materials and relevant LTSOFCs. This involves energy band and built-in-field assisting superionic conduction, highlighting coupling effect among the ionic transfer, band structure and alignment impact. Furthermore, theories of ceria–carbonate, e.g., space charge and multi-ion conduction, as well as new scientific understanding are discussed and presented for functional CHC materials.

Electrochemical performance of La2NiO4+δ-Ce0.55La0.45O2-δ as a promising bifunctional oxygen electrode for reversible solid oxide cells

In this work, La2NiO4+δ-xCe0.55La0.45O2-δ (denoted as LNO-xLDC) with various LDC contents (x = 0, 10, 20, 30 and 40, wt %) were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells (RSOCs). Compared with the pure LNO, the optimum composition of LNO-30LDC exhibited the lowest polarization resistance (Rp) of 0.53 and 0.12 Ω·cm2 in air at 650 and 750 oC, respectively. The enhanced electrochemical performance of LNO-30LDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer channels. The hydrogen electrode supported single cell with LNO-30LDC oxygen electrode displayed peak power densities of 276, 401 and 521 mW·cm-2 at 700, 750 and 800 oC, respectively. Moreover, the electrolysis current density of the single cell demonstrated 526.39 mA·cm-2 under 1.5 V at 800 oC, and the corresponding hydrogen production rate was 220.03 ml·cm-2·h-1. The encouraging results indicated that LNO-30LDC was a promising bifunctional oxygen electrode material for RSOCs.

Ionic Transfer Reactions with Cyclohexadiene-Based Surrogates

A current research program in our laboratory is devoted to the development of cyclohexa-1,4-diene-based surrogates of difficult-to-handle compounds and their application in metal-free ionic transfer reactions. These investigations grew from our interest in silylium ion chemistry and consequently concentrated initially on surrogates of gaseous and explosive hydrosilanes such as Me3SiH and even monosilane (SiH4). Since then, we have expanded the concept to design surrogates of other species including H2, mineral acids (HI and HBr), and hydrocarbons (isobutane and isobutene). This Account summarizes our discoveries in this area to date, describing the challenges we faced along the way and how we combatted them.1 Introduction2 Transfer Hydrofunctionalization: Variation of the Electrofuge3 Transfer Hydrofunctionalization: Variation of the Nucleofuge4 Transfer Hydrohalogenation Using a Modified Surrogate5 Surrogate Synthesis6 Conclusion