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Glass, unlike a crystalline solid, contains atoms and molecules that do not occupy fixed positions. A glass that contains molecules that attract one another can age with time. We report such a glass that contains A2O and (OA)− electric dipoles (A = Li or Na). At a temperature T 10−2 S cm−1 and a huge dielectric constant that makes it suitable for many applications, including safe rechargeable batteries of high energy density and long cycle life.

LiCo 0.8 Ni 0.1 Mn 0.1 O 2 positive electrode material was prepared via the combustion method followed by a thermal treatment at 900 °C for 1 h. A systematic study has been performed to investigate the structural changes of LiCo 0.8 Ni 0.1 Mn 0.1 O 2 upon chemical lithium extraction. X-ray diffraction (XRD), electronic paramagnetic resonance (EPR), and magnetic susceptibility measurements were performed. These experiments provided a detailed picture of the whole delithiation process. Not only oxidation of Ni 2 + ions but also some Co 3 + ions were evidenced at the beginning of the delithiation process. Further lithium extraction induces an insulator to metal transition for the composition Li 0.3 Co 0.8 Ni 0.1 Mn 0.1 O 2 as shown by the plot of χ − 1 (T) vs. T, which is similar to that reported for Li y CoO 2 . The electrochemical performances of the LiCo 0.8 Ni 0.1 Mn 0.1 O 2 sample were measured at different current rates in the 3–4.5 V potential range. This material exhibits good discharge capacity of 180 mAh g − 1 and a columbic efficiency approaching 96%.

Materials having a high dielectric constant are needed for a variety of electrical applications from transistors to capacitors. Ferroelectric amorphous-oxide (glass) alkali-ion electrolytes of composition A2.99Ba0.005ClO (A = Li, Na) are shown by two different types of measurement and different consistent analyses to have extraordinarily high dielectric constants, varying from 109 at 25 °C to 1010 at 220 °C if the glass is properly conditioned. These anomalously high dielectric properties coexist with alkali-ion conductivities at 25 °C that are equivalent to those of the best organic-liquid electrolytes of a Li-ion cell, and cyclic voltammetry (CV) in a Au/glass electrolyte/Au cell is stable from −10 to +10 V. A model to interpret microscopically all the key features of the CV curves shows that the electric-double-layer capacitors that form at the gold/electrolyte interfaces in the Au/glass electrolyte/Au heterojunction reverse polarization at an applied voltage V = ±2.1 V, resulting in three almost equiv...

Precursors of the crystalline antiperovskites A3−xHxOCl (A = Li or Na and 0 < x < 1) can be rendered glass/amorphous solid Li+ or Na+ electrolytes by the addition of water to its solvation limit with/without the addition of a small amount of an oxide or hydroxide. The solvated water is evaporated as HCl and 2(OH)− = O2− + H2O. The O2− attracts a Li+ or Na+ to form dipoles; the remaining Li+ or Na+ are mobile. The Li+ or Na+ ionic conductivities of the glass/amorphous solids have activation energies ΔHm < 0.1 eV and a room-temperature conductivity comparable to that of the best organic liquid electrolytes. Measurements of the dielectric loss tangent versus frequency show two overlapping resonances at room temperature with the Ba-doped Li-glass; they are nearly overlapping at temperatures 41 °C < T < 141 °C in the Ba-doped Na-glass. Galvanostatic charging of a symmetric Cu/Na-glass/Cu cell for 1 h showed a remarkable self-charge on switching to open circuit; charging for 15 h followed by discharging at an applied −0.1 mA of the symmetric cell showed, in the discharge mode, a replating of sodium on the anode at a positive cell current of +0.07 mA for over 15 h. A model for these behaviors is proposed. A symmetric Li/Li-glass/Li cell was cycled to demonstrate plating of Li on a current collector from the Li-glass electrolyte.

The dependence of modern society on the energy stored in a fossil fuel is not sustainable. An immediate challenge is to eliminate the polluting gases emitted from the roads of the world by replacing road vehicles powered by the internal combustion engine with those powered by rechargeable batteries. These batteries must be safe and competitive in cost, performance, driving range between charges, and convenience. The competitive performance of an electric car has been demonstrated, but the cost of fabrication, management to ensure safety, and a short cycle life have prevented large-scale penetration of the all-electric road vehicle into the market. Low-cost, safe all-solid-state cells from which dendrite-free alkali–metal anodes can be plated are now available; they have an operating temperature range from −20 °C to 80 °C and they permit the design of novel high-capacity, high-voltage cathodes providing fast charge/discharge rates. Scale-up to large multicell batteries is feasible.

The Ag-Li system was analysed using first-principles calculations 10.1016/j.jallcom.2019.152811 [1]. The method included using density functional theory to optimize the crystal structure of the phases constituting the binary phase diagram by relaxing atomic positions, volume, and shape. The optimized structures were subsequently used to calculate thermodynamic properties at different temperatures; by determining the zero-point energy, the vibrational internal energy, and the entropy, the heat capacity at constant volume was obtained as well as the phases' stability limits. Furthermore, optimized structures were used to calculate the XRD patterns and to compare them with experimental data. All the referred data are now accessible to researchers and industrials demanding to work with binary and higher-order systems that include Ag and Li, for example, for energy storage. Binaries should be well assessed prior to higher-order phase diagrams and in that resides additional usefulness to this data.

Silicon has been recently used as negative electrode in Li-ion batteries which makes the Li–Si system the focus of numerous studies. In this work, the Li–Si system was studied by means of drop calorimetry, differential scanning calorimetry, first principles calculations and the CALPHAD method. The enthalpies of mixing of the liquid phase were determined for the first time. The optimization started by the liquid phase and was performed using the experimental data. The following steps of the optimization of the thermodynamic properties and assessment of the phase diagram were conducted using the CALPHAD method. According to very recent studies in the literature and with our calculations, Li17Si4, Li21Si5 and Li4.13Si phases were considered as the Li-rich phases instead of Li22Si5. The LiSi phase was also considered for the first time in the assessment. The Li13Si4, Li7Si3 and Li12Si7 phases were also taken into account. Additionally, the crystal structure of the Li–Si phases was established by optimization of the electronic structure of each phase and phonon calculations were performed to attain the thermodynamic data at T > 0 K. The first principles thermodynamic data was compared with experimental and CALPHAD results.

The Ag–Ca phase diagram was optimized and subsequently assessed. New data for the enthalpies of formation of the Ag 9 Ca 2 and AgCa 3 compounds were obtained by means of drop calorimetry. Differential Thermal Analysis experiments were also performed and the resulting concentration/transformation temperatures could be compared with the phase diagram. First principles calculations were performed leading to the Gibbs free energies of each compound as a function of temperature. Tentative structures with possibility of being stable were found for Ag 5 Ca and AgCa 3 compounds. Finally, the CALPHAD method was used to assess the phase diagram as well as all the available results.

The Tetrahedrite’s family constitutes a complete solid-solution series, and is among the most frequent complex sulfides in Nature. This kind of structure can be generically expressed by the composition, Cu12Sb4S13. We have calculated the electronic band structure of Cu12Sb4S13 and Ag6Cu6Sb4S13 (with band gaps of 1.24 and 1.20 eV, respectively) to demonstrate that different elements occupying certain sites of the crystal structure will make a difference in what concerns the conduction process in Tetrahedrites. We will use this effect and ab initio calculations to show that the electronic properties of these compounds make them promising candidates as solar cells photovoltaic materials since not only they possess a direct band gap but their energy falls within the range of energies of photovoltaics. Moreover, we can optimize these properties by doping and substituting ions furthermore. Mechanical properties were also calculated for both compounds and will be compared.

Bi-Sn-Zn is one of the systems being used as substitute of the traditional lead solders. Therefore a deeper knowledge of its phase diagram is a priority. Due to the lack of data about the thermodynamic properties of terminal solid solutions as well as on their phase boundaries, only binary contributions were utilized and the ternary terms were ignored on the published assessments [1, 2]. Samples corresponding to several vertical sections were prepared and DTA, SEM/EDS and XRD at room and high temperatures were performed. It was concluded that ternary terms should be held in consideration in a future assessment of the system.

We have analyzed the hopping movement of a new ionic solid electrolyte by calculating defect formation energies and activation barriers. The role of the lattice during diffusion was established. Thermodynamic properties were determined by means of first principles and phonon calculations at working temperatures. The new solid electrolyte, an antiperovskite, Li3-2xMxAO (in which M is a higher valent cation like Ca2+ or Mg2+ and A is a halide like Cl- or Br- or a mixture of halides), was studied either pure or doped. Moreover, we present experimental ionic conductivity data for these novel solid state ionic conductors for the doped and the pure solid electrolyte from room temperature and up to ∼253 °C. In this paper, we compare the ionic conductivity of the latter solid electrolyte with other fast ionic conductors.

The worldwide demand for energy in the 21st century is growing at an alarming rate. The European “World Energy Technology and Climate Policy Outlook” [WETO] predicts an average growth rate of 1.8% per annum for the period 2000-2030 for the world energy demand (European Commission, 2003). The increased demand is being met largely by reserves of fossil fuel that emit both greenhouse gases and other pollutants. Since the rate of fossil fuel consumption is higher than the rate of fossil fuel production by nature, these reserves are diminishing and they will become increasingly expensive.

The aim of this study is to determine the thermodynamic influence of the presence of Cu3SbS3, Cu2S and Sb2S3 in the formation of Cu12Sb4S13 - equivalent to mineral tetrahedrite. Thus, the Cu-Sb-S system is studied. Twenty three samples, with compositions that essentially lay along the vertical section Cu2S-Sb2S3, were prepared. The samples were analyzed by Electron Microprobe (EPMA) in order to determine the room temperature phases' composition. Samples were also analyzed by Differential Thermal Analysis (DTA/DSC) in order to establish thermal transitions, and by X-Ray Diffraction (XRD), at room and high temperatures, so as to determine the phases that are present in the equilibria at certain temperatures. The experimental phase diagram was established and the results were compared with those available in the literature.