Glycine-nitrate Method Research Articles

Magnetic and magnetostrictive properties of Cu-doped cobalt ferrite

The Cu-doped cobalt ferrites CuxCo1-xFe2O4 (CCFO) were synthesized by a glycine-nitrate sol-gel auto-combustion method and investigated for structural, magnetic and magnetostrictive properties. X-ray diffraction and scanning electron microscopy analysis revealed the formation of single cubic-spinel phase for all the as-prepared powders, followed by the sintered samples with grain sizes around 2.5 µm. The variation in stoichiometric composition can be used to tailor magnetic and magnetostrictive properties. Saturation magnetization MS decreases from 84.8 to 60.4 emu/g with increasing Cu content from x = 0.0 to x = 0.50, accompanied with a reduction in coercivity HC from 1.21 to 0.41 kOe. The introduction Cu into CFO is conductive to the decline in magnetocrystalline anisotropy, giving rise to an improvement in magnetostriction at low applied fields. An optimized composition in the CuxCo1-xFe2O4 ferrites is found to be around x = 0.30, achieving good magnetoelastic properties, i.e., a large saturation magnetostriction (–λS ∼ 240 ppm), a high strain sensitivity (–dλ/dH ∼ 1.44 nm/A), as well as a low magnetocrystalline anisotropy coefficient (K1 ∼ 3.7 × 106 erg/cm3). The excellent magnetoelastic properties and the combination in a facile synthesis process for sintered polycrystalline ferrites, suggest promising prospects in magnetostriction applications.

Boosting the electrocatalytic activity of NdBaCo2O5+δ via calcium co-doping as bifunctional oxygen electrodes for reversible solid oxide cells

The oxygen electrode of the solid oxide cells (SOCs) operates under an oxidizing atmosphere. Lattice shrinkage in a high oxygen partial pressure environment results in cation misalignment, leading to a decline in performance. Addressing the drawbacks associated with A-site cation mismatch in LnBaCo2O5+δ double perovskite oxides for reversible solid oxide cells (RSOCs) oxygen electrodes, a novel calcium ion co-doping strategy is proposed. This approach effectively mitigates A-site cation segregation and enhances stability. The glycine-nitrate method was employed to synthesize Nd0.8Ca0.2Ba1−xCaxCo2O5+δ (x = 0–0.2) layered double perovskites oxides co-doped with calcium ions, denoted as NCBCC. NCBCC exhibits excellent compatibility with commonly used electrolytes. The doping of calcium co-doped in NdBaCo2O5+δ decreases the thermal expansion coefficient and improves the electron transfer characteristics. The sample with x = 0.1 exhibited an area-specific resistance (ASR) of 0.024 Ω cm2 when operated at a temperature of 800 °C in air. In the solid oxide fuel cell mode, employing x = 0.1 as an oxygen electrode, the maximum power density achieved was 766 mW cm−2 at 800 °C. In the solid oxide electrolysis cell mode, operating with CO2 and steam at an electrolysis voltage of 1.5 V and a temperature of 800 °C, the corresponding current densities were −1.51 and −1.85 A cm−2, respectively. The incorporation of calcium ions into layered perovskite oxides offers a promising strategy to enhance the performance of oxygen electrodes in RSOCs.

A-site deficient La1-xCr0.95Ru0.05O3-δ perovskites for N-hexadecane steam reforming: Effect of steam activation and active oxygen

Liquid fuels like diesel, biodiesel, and alcohols can be utilized for onboard hydrogen production in auxiliary power systems by steam reforming, in which hydrogen productivity and carbon deposition are key issues. A-site deficient La1-xCr0.95Ru0.05O3 catalysts are prepared using the Glycine-nitrate method and characterized by multiple techniques. The catalyst with 20 % A-site deficiency exhibits about 95 % fuel conversion and stable performance over a 100 h continuous test at 750 °C and a steam/carbon ratio of 3.0 using n-hexadecane. However, the catalyst with a 10 % deficiency shows fluctuating fuel conversion with higher ethylene and ethane contents. Catalyst performance is mainly determined by active oxygen. The activation of steam on oxygen vacancies and Cr ions with variable valences could produce surface-free oxygen and freely migrating lattice oxygen respectively, which can react with CHx intermediates to form CO and H2.

Synthesis of nanopowders by the glycine-nitrate method in the In-Dy-O system

We investigated the feasibility of synthesizing nanopowders containing indium and dysprosium oxides by the glycine-nitrate method. It was found that the glycine-nitrate method significantly reduces the content of the indium component in the resulting mixture of indium and dysprosium oxides. In this case, intensive absorption of carbon dioxide from the air by the formed particles induces formation of amorphous carbonaceous compounds, which decompose only under high-temperature treatment (900 °C). This prevents compaction of powders synthesized by the glycine-nitrate method. Comparison of the characteristics of powders containing indium oxides and dysprosium, synthesized by the glycine-nitrate method and by the method of co-precipitation of indium and dysprosium hydroxides from chloride solutions, showed the advantage of the co-precipitation method in the pressing of powders.

Effect of Synthesizing Temperature on the Structure and Magnetic Properties of The Co-Ferrite

This study explores the preparation of Co-nano ferrites using the glycine-nitrate auto-combustion method at different synthesis temperatures. The crystal structure, magnetic properties, and morphological traits were investigated using X-rays in diffractometry, a vibrating sample magnetometer, and scanning electron microscopy. Based on the X-ray diffraction (XRD) data, it can be observed that the products produced possess a cubic spinel structure. As the temperature for synthesis is elevated from 100°C to 250°C, there is an observed increase in the size of the crystallites from 21nm to 25nm. Furthermore, an increase in the synthesizing temperature led to a reduction in the lattice constant, which decreased from 8.4155 Å to 8.3565 Å. Scanning electron microscopy (SEM) images, accompanied by histograms, revealed that the ferrite nanoparticles exhibited a tendency to aggregate, as indicated by a variance of around 100 and a standard deviation of 10. The VSM data indicate that an increase in synthesis temperature leads to a corresponding increase in magnetic saturation.

PrBa0.5Sr0.5Co1.5Fe0.5O5+δ as air electrode for proton-conducting solid oxide cells

Proton-conducting solid oxide cell (H–SOC) is suitable for operation at lower temperatures. However, its commercialization still faces the problem of insufficient catalytic activity of air electrode. Here a triple ionic-electronic conductor PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) is synthesized by glycine-nitrate method, and the PBSCF slurry was screen printed onto the surface of half-cell which is fabricated by aqueous co-tape casting to obtain the single cell with the structure of PBSCF ǀ BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) ǀ NiO-BZCYYb (active layer) ǀ NiO-BZCYYb (support layer). The peak power density of the single cell with dry air as oxidant and hydrogen as fuel at 750, 700, and 650 °C are 958.75, 872.78, and 709.22 mW cm−2, respectively. When the atmosphere is 20%H2O+80%air at air electrode side and hydrogen at fuel electrode side, the single cell operating as a proton-conducting solid oxide electrolysis cell shows high electrolysis current densities of 4299.4, 2744.6, 1711.8, and 974.6 mA cm−2 under 1.3 V at 750, 700, 650, and 600 °C respectively. Additionally, during the constant voltage electrolysis, the cell shows a good stability in 78 h at 650 °C. The results show that PBSCF is potential as air electrode of H–SOCs, especially in solid oxide electrolysis cell mode.

Electrochemical properties of four novel high-entropy spinel oxides used as lithium-ion battery anodes synthesized by the glycine-nitrate SCS method

Electrochemical properties of four novel high-entropy spinel oxides used as lithium-ion battery anodes synthesized by the glycine-nitrate SCS method

Enhanced magnetostriction of Co–Ni-ferrite composites derived from hard (CoFe2O4) and soft (NiFe2O4) magnetostrictive phases

We report on the enhanced magnetostrictive characteristics of composites derived from the hard cobalt ferrite (CoFe2O4; CFO) and soft nickel ferrite (NiFe2O4; NFO) materials. The CFO, NFO and CFO-NFO (CNFO) mixed composites (25NFO + 75CFO, 50NFO + 50CFO and 75NFO + 25 CFO) were synthesized by employing a cost-effective and eco-friendly glycine-nitrate autocombustion method. The CFO, NFO and their mixed composites were evaluated to assess their phase purity, surface morphology, magnetic properties, and magnetostrictive characteristics. The X-ray diffraction (XRD) and electron microscopy analyses revealed that the CFO and NFO nanomaterials were phase pure, porous in nature, and nano-sized with average crystallite size of 73 nm (CFO) and 69 nm (NFO). Subsequently, the Co–Ni-ferrite composite made from CFO and NFO in equal quantity by sintering at 1200 °C indicate that the lattice parameter, a, of the composite lies in between the lattice parameters of respective components (CFO-8.390 Å and NFO-8.343 Å) indicating that both phases co-exists as single-phase in the composite. The grains of the sintered compounds are nearly spherical shape with the average sizes ∼670 nm, ∼550 nm and ∼560 nm, respectively, for CFO, NFO and 50NFO +50CFO composite. Due to grain growth upon sintering, magnetizations of the sintered CFO and NFO nanomaterials are higher than that of as-synthesized samples. Interestingly, the magnetization curves of sintered CNFO composites exhibit symmetric nature (single loop), where their magnetization lies in between the magnetizations of NFO and CFO phases, indicating a proper exchange coupled between the two phases. The composites demonstrate better magnetostriction at lower magnetic fields than the parent sintered CFO and NFO samples. At an applied magnetic field of 2 kOe, the obtained magnetostriction value for 50NFO +50CFO composite (−120 ppm) is nearly 500% higher than that of CFO (−20 ppm) and 300% higher than that of NFO (−30 ppm). The structure-phase-property correlation established in these composites expected to provide a road-map for their possible applications in electromagnetic devices.

Magnesium Spinel Ferrites Development for FDM 3D-Printing Material for Microwave Absorption

The magnesium nanosized ferrite powder with formula MgFe2O4 was synthesized via a pyrochemical sol–gel glycine–nitrate method and annealed consistently at temperatures of up to 1300 °C. The MgFe2O4 ferrite samples’ microstructure was studied by SEM and XRD methods. According to the results of the studies, the increase in MgFe2O4 nanoparticles size from about 15 nm to micron-sized particles was observed when increasing annealing temperatures. The DC electrical conductivity of MgFe2O4 also clearly shows the change in conduction behavior of samples with increased calcination temperatures. The electromagnetic microwave properties of micron-sized particles of MgFe2O4 ferrite powder for a 1200 °C annealing temperature were studied for composites in paraffin matrix with produced magnetic filler mass concentration at 40% and 50%. The filament composites of polymer polylactic acid with MgFe2O4 ferrite powder samples were prepared by the FDM 3D-printing process and their microwave-absorbing properties were investigated. The application of developed PLA–MgFe2O4 ferrite filament for fabricating magnetic microwave-absorbing components also was demonstrated.

Direct Electrophoretic Deposition and Characterization of Thin-Film Membranes Based on Doped BaCeO3 and CeO2 for Anode-Supported Solid Oxide Fuel Cells.

In this work, a technology was developed for the formation of BaCe0.8Sm0.2O3+1 wt% CuO (BCS-CuO)/Ce0.8Sm0.2O1.9 (SDC) thin-film electrolyte membranes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) on porous NiO-BCS-CuO anode substrates using direct electrophoretic deposition (EPD). The effect of increasing the zeta potential when modifying the base suspension of a micro-sized SDC-gn powder (glycine–nitrate method) with the addition of a SDC-lec nanopowder (laser evaporation–condensation) was investigated. Dependences of the current strength on the deposition time and the deposited weight on the EPD voltage were obtained, and evolution of the morphology of the coatings during the modification of the SDC-gn suspension and a suspension of BCS-CuO powder was studied. The compatibility of the shrinkage kinetics of the SDC, the BCS-CuO electrolyte coatings and the NiO-BCS-CuO anode substrate was studied during the high-temperature sintering. Dense BCS-CuO/SDC films of different thicknesses were obtained for the first time on porous NiO-BCS-CuO anode substrates and comprehensive microstructural and electrochemical studies were carried out. The developed technology can be applied to the formation of anode-supported SOFCs with thin-film electrolyte membranes.

Glycine-nitrate auto-combustion synthesis and magnetic properties of nanocrystalline NdAlxFe1–xO3 perovskites

The effect of substitution of Fe3+ by Al3+ on the structure and magnetic properties of NdAlxFe1–xO3 perovskite nano-powders (x = 0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) prepared by the glycine-nitrate auto-combustion method was studied. All samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and energy dispersive X-ray spectroscopy (EDX). The magnetic properties of the samples were investigated using a vibrating sample magnetometer (VSM). The X-ray results for all samples reveal the formation of an orthorhombic perovskite phase (space group Pbnm) with no secondary phase. The crystallite sizes of the nanoparticles are found to decrease with increasing Al content, and are in the range of 53–38 nm. SEM images show spherical nanoparticles with agglomeration. The FT-IR spectra confirm the presence of metal oxygen bonds. The M–H loop of the pristine NdFeO3 sample is antiferromagnetic in the a/b plane with weak ferromagnetism in the c-axis. Introducing Al inclusions in the pristine polycrystal thereby creating magnetic vacancies is seen to influence the magnetic properties. The magnetic dilution results in enhanced magnetisation at low Al content; x = 0.1, 0.2 (saturation magnetisation being 2.08 and 2.05 emu/g, respectively) compared to the pristine sample with a saturation magnetisation of 1.43 emu/g due to increased exchange interaction. Also dilution with nonmagnetic dopant induces the phase transition from weak ferromagnetic to paramagnetic depending on the impurity concentration. The coercive field for NdFeO3 is found to be equal to 1950 Oe and decreases with Al-substitution. These findings lay a ground work for research in tuning magnetic properties and in spintronics with potential applications in data storage, switches and electronic devices.

LaNi0.6Co0.4−xFexO3−δ as Air-Side Contact Material for La0.3Ca0.7Fe0.7Cr0.3O3−δ Reversible Solid Oxide Fuel Cell Electrodes

The goal of the current work was to identify an air-side-optimized contact material for La0.3Ca0.7Fe0.7Cr0.3O3−δ (LCFCr) electrodes and a Crofer22APU interconnect for use in reversible solid oxide fuel cells (RSOFCs). LaNi0.6Co0.4−xFexO3 (x = 0–0.3) perovskite-type oxides were investigated in this work. The partial substitution of Co by Fe decreased the thermal expansion coefficient values (TEC) closer to the values of the LCFCr and Crofer 22 APU interconnects. The oxides were synthesized using the glycine–nitrate method and were characterized using X-ray thermodiffraction and 4-probe DC electrical conductivity measurements. Based on the materials characterization results from the Fe-doped oxides investigated here, the LaNi0.6Co0.2Fe0.2O3−δ composition was selected as a good candidate for the contact material, as it exhibited an acceptable electrical conductivity value of 395 S·cm−1 at 800 °C in air and a TEC value of 14.98 × 10−6 K−1 (RT-900 °C).

Anomalous structural transformations of Gd-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=- nanopowders obtained in the combustion mode by the glycine-nitrate method

The structural states of Gd2O3 and Gd2O3 : 2% Eu3+ synthesized by the glycine-nitrate method were studied. As a result of this synthesis, in addition to the known cubic modification of gadolinium oxide, two new previously unknown phases are formed. The first phase is formed during prolonged exposure at room temperature of the initial nanocrystalline cubic structure obtained at a synthesis temperature of 650oC. The second phase has orthorhombic syngony and is formed during either long-term synthesis at a temperature of 650oC, or short-term syntheses at a higher temperature. Both phases pass into the traditional cubic modification during further high-temperature annealing. In addition, the effect of structural "infection" was found, which consists in the fact that during annealing of the cubic phase of Gd2O3 doped with Eu3+ ions in the range of 800-1100oC, its partial transition into the monoclinic phase occurs, which disappears with a further increase in the annealing temperature. Keywords: synthesis of Gd2O3, glycine-nitrate method, nanocrystalline state, X-ray diffraction research methods, phase transitions.

Tetragonal nanocrystalline phases in oxides Re-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-

X-ray diffractometric studies of the structural state of simple rare-earth oxides Gd2O3, Sm2O3 and Eu2O3 were carried out, synthesized by different methods, at the first stages of crystal formation. It was found that the first crystalline phase of these compounds in the nanocrystalline state is not a known cubic modification with the spatial symmetry group S.G. Ia-3 (206), but tetragonal phases, whose spatial groups are not established due to the small number of strong reflexes in the nanostate. It is also shown that the same tetragonal phases are formed in industrial powders of these compounds subjected to long-term storage. Keywords: synthesis of Re2O3, glycine-nitrate method, nanocrystalline state, X-ray diffraction research methods, phase transitions.

Glycine-nitrate derived cobalt-doped BiPO4: An efficient OER catalyst for alkaline electrochemical cells

The investigation of cost effective and earth abundant electro-catalyst to catalyze oxygen evolution reaction (OER) is highly desirable for the development of future sustainable energy. Herein, a facile one step glycine-nitrate decomposition method has been proposed to synthesize crystalline un-doped and cobalt doped BiPO4. The prepared un-doped and cobalt doped BiPO4 have been evaluated as potential electro-catalysts for OER. The XRD, XPS and ICP-OES results reveal that BiPO4 undergo surface reconstruction during OER and thereby converted into Bi2O3. Thus, the in situ formed Bi2O3 is the real active catalyst to catalyze OER where 5% cobalt doped BiPO4 exhibits excellent OER activity in terms of low overpotential of 328 mV and 394 mV to afford the current density of 10 and 50 mA cm−2 respectively, which is much lower than that of the un-doped BiPO4 (480 mV). Besides, the polarization curves of 5% cobalt doped BiPO4 shows negligible difference in overpotential even after 20 h of continuous electrolysis, demonstrating excellent stability in alkaline KOH. This work demonstrates intrinsic electro-catalytic activity of phosphate based electro-catalyst can be improved by doping with suitable transition metal and through surface reconstruction.

Lithium-Cation Conductivity of Solid Solutions in Li6-xZr2-xAxO7 (A = Nb, Ta) Systems.

Li6-xZr2-xAxO7 (A = Nb; Ta) system with 0 < x < 0.30 is synthesized by glycine-nitrate method. Boundaries of solid solutions based on monoclinic Li6Zr2O7 are determined; temperature (200–600 °C) and concentration dependences of conductivity are investigated. It is shown that monoclinic Li6Zr2O7 exhibits better transport properties compared to its triclinic modification. Li5.8Zr1.8Nb(Ta)0.2O7 solid solutions have a higher lithium-cation conductivity at 300 °C compared to solid electrolytes based on other lithium zirconates due the “open” structure of monoclinic Li6Zr2O7 and a high solubility of the doping cations.

Operando XRD study on the Effect of Boron Doping on the Failure Mechanisms of Na-, Ni- and Mn-based Positive Electrodes in Sodium-Ion Batteries

In this work, Na0.64Ni0.31Mn0.68O2 was synthesized via the glycine-nitrate combustion synthesis method and investigated as positive electrode material in sodium-ion batteries. Na-, Ni- and Mn-based layered oxide positive electrode materials are prone to capacity fade. In this study, boron was investigated as an additive to increase capacity retention. The physical properties of obtained positive electrode materials were characterized using XRD and XRF. The materials were electrochemically characterized using the galvanostatic charge-discharge method. In addition, the material with the highest initial capacity was further examined using the operando XRD method to characterize the changes in the material's crystal lattice in real-time during galvanostatic cycling.

Optimization of Contact Cathode Composition Based on La0.8Sr0.2MnO3±δ for SOFC Stacks

A stack based on planar solid oxide fuel cells (SOFCs) is an assembly of ceramic plates - membrane-electrode assemblies (MEA) and metal current collectors, which play the role of the distribution of gas mixtures over the electrode area, as well as current collection. In order to organize the high-quality current collection it’s necessary to provide a reliable electrical contact between the MEA’s electrodes and contact surfaces of the current collectors. Electrical contact between MEAs’ anode electrode and the collector is achieved by pressing the contact nickel meshes. Metal-based conductive adhesives are also used to reduce the contact resistance at the anode electrode. Despite this in order to ensure contact between the MEA’s cathode electrode and the collector this approach is not applicable due to the rapid oxidation of contact meshes in air atmosphere at high temperatures. In turn, contact pastes based on conductive ceramics do not have such a drawback and make it possible to ensure reliable contact under the conditions of the SOFC cathode chamber.Materials for the contact adhesive for the SOFC cathode chamber must be chemically and thermomechanically compatible with the materials of the SOFC cathode and bipolar plate along with high electrical conductivity. These requirements are met by materials based on lanthanum strontium manganite oxide (LSM) materials, which are widely used as cathode materials for SOFCs. It should be noted that the contact adhesive must also correspond to the limitations of technological processes of SOFC stack manufacturing. SOFC stacks are sealed with glass in a temperature range of 930-950°C, so it’s necessary to use a material that forms a conductive contact at temperatures not higher than 950°C, which is significantly lower than typical sintering temperatures of LSM-based cathode.The synthesis of single-phase highly dispersed powders with the composition of La0.8Sr0.2MnO3±δ (LSM) and (La0.8Sr0.2)0.97MnO3±δ (LSM-d) was carried out by the glycine-nitrate method. After synthesis some of the obtained materials were ball-milled in ethanol using 5 mm ceramic milling bodies at a speed of 600 rpm for 300 and 600 min. A mixture of polyvinyl butyral, toluene, and butanol was used as the basis for the contact paste.Tests of the electrical conductive properties of contact pastes were carried out in air in temperature range of 600-950°C. Samples were kept for 2 hours before cooling at the maximum temperature. Figure shows the results of resistivity measurements: the dashed lines represent the values obtained when the sample was cooled.The maximum values of the resistivity at a temperature of 850°C were obtained for contact adhesive samples based on non-activated stoichiometric (LSM) and A-deficient (LSM-d) powders. Low electrical conductivity can be associated with weak intergranular contact due to the strong agglomeration of the material after synthesis. Grinding for 300 minutes results in a noticeable reduction in the resistivity of the contact adhesive (LSM-300). Change in resistivity after holding at maximum temperature, as well as the change in the slope of the temperature dependence of the resistivity of the adhesive based on LSM-300 indicates the sintering of the contact adhesive powder into a ceramic compact, which is confirmed by SEM results. In turn, holding at a temperature of 950°C of contact adhesive based on LSM-600 (600 min grinding pre-activated) powder does not lead to its sintering.Grinding of the initially single-phase LSM powder results in the appearance of additional reflections in the XRD-spectrum corresponding to the Sr(OH)2 and MnCO3 phases. An increase in the grinding time leads to an increase in the proportion of impurity phases that prevent the contact adhesive from sintering at temperatures <950°C.Thus, the best results were shown by a contact adhesive based on stoichiometric LSM powder, pre-activated by grinding for 300 minutes. Holding at a temperature of 950°C leads to sintering of LSM-300 powder into ceramics, which makes it possible to form a reliable electrical contact under the conditions of the SOFC cathode chamber.We have proposed a method for the manufacture and deposition of a contact cathode composition based on La0.8Sr0.2MnO3±δ. It is shown that the initial powders obtained by the glycine-nitrate method according to the Pechini modification are preliminary prepared. The optimal grinding parameters have been determined. The sintering modes of the contact paste are selected, which are consistent with those for the sealing glass. An experimental SOFC assembly was made using a contact cathode paste. It is shown that the electrochemical characteristics of individual MEAs correspond to the declared ones and the specific power reaches 0.25W/cm2.This work was carried out with financial support from the Russian Scientific Foundation, grant no. 17-79-30071. Figure 1

Electrical Properties of Novel La0. 2Sr0.7-xCaxTi0.95Fe0.05O3-δ Based Fuel Electrode for Solid Oxide Cell

A novel La0. 2Sr0.7-xCaxTi0.95Fe0.05O3-δ (LSCFT-x) fuel electrode compositions for high-temperature solid oxide fuel cell application are synthesized using glycine-nitrate synthesis method. To understand the influence of Sr/Ca ratio on electrical conductivities of different compositions of LSCFT, the DC four-probe conductivity measurements of porous electrode layers has been performed. Conductivities have been measured at three different atmospheres: air, 1% H2 + 3% H2O + 96% Ar, and 97% H2 + 3% H2O. The crystal structure and microstructure have been studied using X-ray diffraction and SEM, respectively to confirm the phase purity and visualize the microstructure of studied electrode layers. It has been shown that the LSCTF material behave like semiconductor and the conductivity is significantly dependent of Ca concentration in A-site. The maximal total electrical conductivity of porous electrode layer made of LSCFT was 5.5 S cm− 1 at 850°C characteristic for the LSCFT-45 material in 97% H2 + 3% H2O atmosphere.

The NaxMnO2 materials prepared by a glycine-nitrate method as advanced cathode materials for aqueous sodium-ion rechargeable batteries

Cathodic material for sodium-ion rechargeable batteries based on NaxMnO2 were synthesized by glycine nitrate method and subsequent annealing at high temperatures. Different crystal structures with different morphologies were obtained depending on the annealing temperature: hexagonal layeredα-Na0.7MnO2.05 nanoplates were obtained at 850 °C, while 3-D tunnel structured Na0·4MnO2 and Na0·44MnO2, both with rod-like morphology, were obtained at 800 °C and 900 °C, respectively. The investigations of the electrochemical behavior of obtained cathodic materials in aqueous NaNO3 solution have shown that Na0·44MnO2 obtained at 900 °C has shown the best battery performance. Its initial discharge capacities are 123.5 mA h/g, 113.2 mA h/g, and 102.0 mA h/g at the high current densities of 1000, 2000 and 5000 mA/g, respectively.