Chemical stability aspects of BaCe0.7–xFexZr0.2Y0.1O3–δ mixed ionic-electronic conductors as promising electrodes for protonic ceramic fuel cells

Mixed ion-electron conductors (MIECs) are promising materials for air electrodes for protonic ceramic fuel cells (PCFCs) or oxygen permeation membranes. In this work, various aspects of the chemical stability of Co-free MIEC materials, BaCe0.7–xFexZr0.2Y0.1O3–δ, were studied, including their interaction with another functional material (BaCe0.5Zr0.3Y0.1Yb0.1O3–δ-based proton-conducting electrolyte) and gas components (H2O, CO2, and H2). Chemical compatibility studies indicate no visible chemical interaction between the electrode and electrolyte materials even at 1200 °C, which is significantly higher than the operating temperatures (600–800 °C) of PCFCs. The treatments of BaCe0.7–xFexZr0.2Y0.1O3–δ in different atmospheres at 1100 °C, according to the XRD, SEM, IR and Raman spectroscopy data, resulted in the formation of impurity phases. However, their extremely small amounts suggest that they may not form at the operating temperatures. Thus, it can be assumed that the studied materials can be good candidates for various electrochemical applications

Heat of Fusion of Na3AlF6 Eutectic Mixtures with CaF2 and Al2O3

The heat of fusion of eutectic mixtures of sodium cryolite with alumina and calcium fluoride was measured using differential scanning calorimetry. Melting temperatures were found to be in good agreement with literature data. The molar heat of fusion of cryolite salts and eutectic mixtures was found to be directly dependent on melting temperature. The temperature dependence coefficient is the same as that of alkali halides

The Category of Colour Naming in English, German and Mari Idioms

Colour naming is reflected in all the languages of the world, namely, in phraseological units where one of the components denotes a colour. The objective of the article is to study idioms in three unrelated languages: English, German and Mari and to reveal how they are organized around universal focal colours. The article analyses 205 idioms of the English language, where one of the components includes colour naming. The research shows that in the English language ‘black’ (47 units, 23 %), ‘blue’ (39 units, 19 %), ‘red’ (32 units, 16 %) and ‘white’ (32 units, 16 %) form the core of the category. In the German language 185 phraseological units have been found, among which ‘schwarz/black’ (42 units, 21 %), ‘grün/green’ (36 units, 20 %) and ‘blau/blue’ (35 units, 19 %) are dominating colours. In the Mari language – 18 idioms: ‘шем/black’ (8 units, 44,5 %), the same amount of ‘ош/white’ (8 units, 44,5 %),‘ ужар/green’ (1 idiom, 5,5 %) and ‘йошкар/red’ (1 idiom, 5,5 %). Taking into account their semantic meaning, all the idioms in three languages have been divided into nine groups. According to their semantic organization, four classes of idioms have been distinguished. DOI: 10.5901/mjss.2015.v6n3s7p3

A Study of Li_3.8Ge_0.9S_0.1O₄ Solid Electrolyte Stability Relative to Electrode Materials of Lithium Power Sources

The stability of Li3.8Ge0.9S0.1O4 lithium-conducting solid electrolyte versus lithium metal and Li–V bronze Li1.3V3O8 is studied in the present research. Isothermal heat treatment and thermal analysis of the mixtures of Li1.3V3O8 and Li3.8Ge0.9S0.1O4 powders indicate that there is no interaction between them below 300–350 °C. Moreover, Li3.8Ge0.9S0.1O4 solid electrolyte is stable versus lithium at 100 °C for 240 h. A model of a lithium-ion power source with a Li1.3V3O8-based cathode and a lithium metal anode is assembled and tested. The data obtained show that Li3.8Ge0.9S0.1O4 can be used in all-solid-state medium-temperature lithium and lithium-ion batteries

A Study of Li3.8Ge0.9S0.1O4 Solid Electrolyte Stability Relative to Electrode Materials of Lithium Power Sources

The stability of Li3.8Ge0.9S0.1O4 lithium-conducting solid electrolyte versus lithium metal and Li–V bronze Li1.3V3O8 is studied in the present research. Isothermal heat treatment and thermal analysis of the mixtures of Li1.3V3O8 and Li3.8Ge0.9S0.1O4 powders indicate that there is no interaction between them below 300–350 °C. Moreover, Li3.8Ge0.9S0.1O4 solid electrolyte is stable versus lithium at 100 °C for 240 h. A model of a lithium-ion power source with a Li1.3V3O8-based cathode and a lithium metal anode is assembled and tested. The data obtained show that Li3.8Ge0.9S0.1O4 can be used in all-solid-state medium-temperature lithium and lithium-ion batteries

Li[1,5]Al[0,5]Ge[1,5](Po[4])[3] glass-ceramics as solid electrolyte for lithium batteries: conductivity and stability versus lithium

Было определено, что фазовый состав и молекулярная структура стеклокерамики не изменяется после контакта с расплавленным литием. Было установлено, что стеклокерамика химически устойчива в контакте с высокоэнергетическим литиевым анодом и может быть использована в качестве твердого электролита в среднетемпературных источниках питания

Physico-Chemical Properties of NaV₃O₈ Prepared by Solid-State Reaction

Sodium–vanadium oxide NaV3O8 is synthesized via solid-state method and optimum synthesis conditions are chosen based on the data of DSC and TG analysis. The material synthesized is characterized by X-ray phase analysis, Raman spectroscopy and scanning electron microscopy. The ratio V4+/V5+ in the sample obtained is determined by X-ray photoelectron spectroscopy. Conductivity of the material synthesized was measured by impedance spectroscopy, pulse potentiometry and DC method over the range RT–570 °C. It is shown that NaV3O8 has rather high conductivity essentially electron in type (6.3 × 10−2 at room temperature). AC and DC conductivity measurements are performed and cycling of symmetricNaV3O8|Na3.85Zr1.85Nb0.15Si3O12|NaV3O8 cell in galvanostatic conditions. Thermal stability is studied across 25–570 °C temperature range. The results obtained are compared with the properties of NaV3O8 produced via aqueous solution

Impact of Li3BO3 Addition on Solid Electrode-Solid Electrolyte Interface in All-Solid-State Batteries

All-solid-state lithium-ion batteries raise the issue of high resistance at the interface between solid electrolyte and electrode materials that needs to be addressed. The article investigates the effect of a low-melting Li3BO3 additive introduced into LiCoO2- and Li4Ti5O12-based composite electrodes on the interface resistance with a Li7La3Zr2O12 solid electrolyte. According to DSC analysis, interaction in the studied mixtures with Li3BO3 begins at 768 and 725 °C for LiCoO2 and Li4Ti5O12, respectively. The resistance of half-cells with different contents of Li3BO3 additive after heating at 700 and 720 °C was studied by impedance spectroscopy in the temperature range of 25–340 °C. It was established that the introduction of 5 wt% Li3BO3 into LiCoO2 and heat treatment at 720 °C led to the greatest decrease in the interface resistance from 260 to 40 Ω cm2 at 300 °C in comparison with pure LiCoO2. An SEM study demonstrated that the addition of the low-melting component to electrode mass gave better contact with ceramics. It was shown that an increase in the annealing temperature of unmodified cells with Li4Ti5O12 led to a decrease in the interface resistance. It was found that the interface resistance between composite anodes and solid electrolyte had lower values compared to Li4Ti5O12|Li7La3Zr2O12 half-cells. It was established that the resistance of cells with the Li4Ti5O12/Li3BO3 composite anode annealed at 720 °C decreased from 97.2 (x = 0) to 7.0 kΩ cm2 (x = 5 wt% Li3BO3) at 150 °C

Solid Electrolyte Membranes Based on Li2O–Al2O3–GeO2–SiO2–P2O5 Glasses for All-Solid State Batteries

Rechargeable Li-metal/Li-ion all-solid-state batteries due to their high safety levels and high energy densities are in great demand for different applications ranging from portable electronic devices to energy storage systems, especially for the production of electric vehicles. The Li1.5Al0.5Ge1.5(PO4)3 (LAGP) solid electrolyte remains highly attractive because of its high ionic conductivity at room temperature, and thermal stability and chemical compatibility with electrode materials. The possibility of LAGP production by the glass-ceramic method makes it possible to achieve higher total lithium-ion conductivity and a compact microstructure of the electrolyte membrane compared to the ceramic one. Therefore, the crystallization kinetics investigations of the initial glass are of great practical importance. The present study is devoted to the parent glasses for the production of Li1.5+xAl0.5Ge1.5SixP3−xO12 glass-ceramics. The glass transition temperature Tg is determined by DSC and dilatometry. It is found that Tg decreases from 523.4 (x = 0) to 460 °C (x = 0.5). The thermal stability of glasses increases from 111.1 (x = 0) to 188.9 °C (x = 0.3). The crystallization activation energy of Si-doped glasses calculated by the Kissinger model is lower compared to that of Si-free glasses, so glass-ceramics can be produced at lower temperatures. The conductivity of the glasses increases with the growth of x content