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Solid electrolytes with superionic conductivity are required as a main component for all-solid-state batteries. Here we present a novel solid electrolyte with three-dimensional conducting pathways based on "lithium-rich" phosphidosilicates with ionic conductivity of σ > 10-3 S cm-1 at room temperature and activation energy of 30-32 kJ mol-1 expanding the recently introduced family of lithium phosphidotetrelates. Aiming toward higher lithium ion conductivities, systematic investigations of lithium phosphidosilicates gave access to the so far lithium-richest compound within this class of materials. The crystalline material (space group Fm3m), which shows reversible thermal phase transitions, can be readily obtained by ball mill synthesis from the elements followed by moderate thermal treatment of the mixture. Lithium diffusion pathways via both tetrahedral and octahedral voids are analyzed by temperature-dependent powder neutron diffraction measurements in combination with maximum entropy method and DFT calculations. Moreover, the lithium ion mobility structurally indicated by a disordered Li/Si occupancy in the tetrahedral voids plus partially filled octahedral voids is studied by temperature-dependent impedance and 7Li NMR spectroscopy.

Lithium iron phosphate LiFePO4 triphylite is now one of the core positive electrode (cathode) materials enabling the Li-ion battery technology for stationary energy storage applications, which are ...

All-solid-state batteries are promising candidates for next-generation energy-storage devices. Although the list of candidate materials for solid electrolytes has grown in the past decade, there ar...

This scientific article deals with the use of index analysis for the assessment of the competitiveness of national food products within the system of international agri-food production competitiveness. The primary objective of this scientific article is the calculation of the actual comparative advantages of separate countries of the world in foreign trade in agri-food products using the RCAij (relative trade advantages) index. First, the pattern of international competitiveness of the most important agri-food items exported by Ukraine is determined on the basis of calculation of RCAij, following which measures are proposed to raise the level of competitiveness of these national food products within world food markets. Calculations of the RCAij indices of revealed comparative advantage (RCA) have shown that Ukrainian agri-food industry in 2017 moved into third place in the level of international competitiveness. Comparative advantages, i.e. calculations using the actual comparative advantages index RCAij, were determined. These calculations demonstrate that the greatest comparative advantages in 2017 were shown by Argentina (RCAij=4.503), New Zealand (RCAij=4.361), Brazil (RCAij=2.558), and Chile (RCAij=1.324). These results show the great share of agri-food exports as compared to the overall exports of goods of the said countries, each with comparatively small volumes of food imports. The value of the index of actual comparative advantages of Ukraine reached 1.131, a result that demonstrates insignificant comparative advantages within the world market, which we link with the average volume of food products imports.

Inorganic lithium-ion conductors have garnered considerable attention as separators for all-solid-state lithium-ion battery applications, given their potential to solve the safety issues and improve the energy and power densities of conventional devices possessing liquid electrolytes. However, achieving this transition requires the optimization of solid electrolyte materials and thus, developing a better understanding of the structure–property relationships, that govern ionic transport, is of crucial importance. Herein, inspired by the growing technological interest, a systematic study on the correlations between structural modifications and transport properties in the thio-LISICON family resulting from the substitution of Ge4+ by Sn4+ within Li4Ge1–xSnxS4 has been conducted. Using Rietveld refinements against neutron diffraction data coupled with maximum-entropy method analyses of nuclear densities, a rigorous investigation into the Li+ diffusion pathways was performed. The substitution of Ge4+ by Sn4+ i...

Anionic redox is a double-edged sword for Li-ion cathodes because it offers a transformational increase in energy density that is also negated by several detrimental drawbacks to its practical implementation. Among them, voltage hysteresis is the most troublesome because its origin is still unclear and under debate. Herein, we tackle this issue by designing a prototypical Li-rich cation-disordered rock-salt compound Li1.17Ti0.33Fe0.5O2 that shows anionic redox activity and exceptionally large voltage hysteresis while exhibiting a partially reversible Fe migration between octahedral and tetrahedral sites. Through combined in situ and ex situ spectroscopic techniques, we demonstrate the existence of a non-equilibrium (adiabatic) redox pathway enlisting Fe3+/Fe4+ and O redox as opposed to the equilibrium (non-adiabatic) redox pathway involving sole O redox. We further show that the charge transfer from O(2p) lone pair states to Fe(3d) states involving sluggish structural distortion is responsible for voltage hysteresis. This study provides a general understanding of various voltage hysteresis signatures in the large family of Li-rich rock-salt compounds. The use of anionic redox chemistry in high-capacity Li-rich cathodes is being hampered by voltage hysteresis, the origin of which remains obscure. Now it has been shown that sluggish ligand-to-metal charge transfer kinetically traps an intermediate Fe4+ species and is responsible for voltage hysteresis in the prototypical Li-rich cation-disordered rock-salt Li1.17Ti0.33Fe0.5O2.

Accurate capacity estimation is critical for reliable and safe operation of lithium-ion batteries. A proposed approach exploiting features from the relaxation voltage curve enables battery capacity estimation without requiring previous cycling information. Machine learning methods are used in the approach. A dataset including 27,330 data units are collected from batteries with LiNi0.86Co0.11Al0.03O2 cathode (NCA battery) cycled at different temperatures and currents until reaching about 71% of their nominal capacity. One data unit comprises three statistical features (variance, skewness, and maxima) derived from the relaxation voltage curve after fully charging and the following discharge capacity for verification. Models adopting machine learning methods, i.e., ElasticNet, XGBoost, Support Vector Regression (SVR), and Deep Neural Network (DNN), are compared to estimate the battery capacity. Both XGBoost and SVR methods show good predictive ability with 1.1 % root-mean-square error (RMSE). The DNN method presents a 1.5% RMSE higher than that obtained using ElasticNet and SVR. 30,312 data units are extracted from batteries with LiNi0.83Co0.11Mn0.07O2 cathode (NCM battery). The model trained by the NCA battery dataset is verified on the NCM battery dataset without changing model weights. The test RMSE is 3.1% for the XGBoost method and 1.8% RMSE for the DNN method, indicating the generalizability of the capacity estimation approach utilizing battery voltage relaxation.

We report magnetic, transport, neutron diffraction, and muon spin rotation data showing that Pb$_2$CoOsO$_6$, a newly synthesized metallic double-perovskite with a centrosymmetric space group at room temperature, exhibits a continuous second-order phase transition at 45 K to a magnetically ordered state with a non-centrosymmetric space group. The absence of inversion symmetry is very uncommon in metals, particularly metallic oxides. In contrast to the recently reported ferroelectric-like structural transition in LiOsO$_3$, the phase transition in Pb$_2$CoOsO$_6$ is driven by a long-range collinear antiferromagnetic order, with propagation vector $\textbf{k} = (\frac{1}{2},0,\frac{1}{2})$, which relieves the frustration associated with the symmetry of themagnetic exchanges. This magnetically-driven loss of inversion symmetry represents a new frontier in the search for novel metallic behavior., 5 pages, 3 figures

Accurate capacity estimation is crucial for the reliable and safe operation of lithium-ion batteries. In particular, exploiting the relaxation voltage curve features could enable battery capacity estimation without additional cycling information. Here, we report the study of three datasets comprising 130 commercial lithium-ion cells cycled under various conditions to evaluate the capacity estimation approach. One dataset is collected for model building from batteries with LiNi0.86Co0.11Al0.03O2-based positive electrodes. The other two datasets, used for validation, are obtained from batteries with LiNi0.83Co0.11Mn0.07O2-based positive electrodes and batteries with the blend of Li(NiCoMn)O2 - Li(NiCoAl)O2 positive electrodes. Base models that use machine learning methods are employed to estimate the battery capacity using features derived from the relaxation voltage profiles. The best model achieves a root-mean-square error of 1.1% for the dataset used for the model building. A transfer learning model is then developed by adding a featured linear transformation to the base model. This extended model achieves a root-mean-square error of less than 1.7% on the datasets used for the model validation, indicating the successful applicability of the capacity estimation approach utilizing cell voltage relaxation.

Among the different piezoceramics, ${\mathrm{Na}}_{0.5}{\mathrm{Bi}}_{0.5}\mathrm{Ti}{\mathrm{O}}_{3}$ (NBT)-based systems have the unique distinction of exhibiting very large electrostrain $(g0.5%)$ when pushed at the threshold of ergodic--nonergodic relaxor transition. However, this strategy severely compromises the system's weak-signal piezoelectric response (${d}_{33}$). Here, we show that a similar level of electrostrain is feasible together with high ${d}_{33}$ by a different approach. In our approach, the system is kept well within the nonergodic relaxor regime close to an interferroelectric instability, and the inherent structural (tilt) disorder is exploited for large reverse switching of the ferroelastic domains in the field-stabilized ferroelectric phase. A synergy of this combination is demonstrated in $(1\ensuremath{-}x){\mathrm{Na}}_{0.5}{\mathrm{Bi}}_{0.5}\mathrm{Ti}{\mathrm{O}}_{3\ensuremath{-}}(x){\mathrm{K}}_{0.5}{\mathrm{Bi}}_{0.5}\mathrm{Ti}{\mathrm{O}}_{3}$; $x=0.25$ which exhibit electrostrain of \ensuremath{\sim}0.6% and ${d}_{33}$ (\ensuremath{\sim}210 pC/N). With the added advantage of high depolarization temperature $({T}_{d}\ensuremath{\sim}185{\phantom{\rule{4pt}{0ex}}}^{\ensuremath{\circ}}\mathrm{C})$ this piezoceramic stands unique for showing the best combination of the three most sought after properties.

The structural complexities of the lead-free piezoelectric system $(1\text{\ensuremath{-}}x){\mathrm{Na}}_{0.5}{\mathrm{Bi}}_{0.5}{\mathrm{TiO}}_{3}\text{\ensuremath{-}}x{\mathrm{BaTiO}}_{3}$ (NBT-BT) continues to pose challenge regarding understanding the mechanisms underlying several interesting phenomena. Issues like (i) whether thermal depoling across compositions is triggered by a structural transformation event or not, (ii) what causes the average Cc structure to partially transform to $R3c$ at $x\ensuremath{\sim}0.03$ in unpoled specimens, (iii) what makes complete depoling of the compositions $0.03\ensuremath{\le}x\ensuremath{\le}0.05$ occur in a considerably small temperature interval as compared to those for $xl0.03$, (iv) what makes the $R3c$-$P4bm$ transition temperature $({T}_{2})$ abruptly become smaller than the depolarization temperature $({T}_{d})$ at $x=0.06$, etc., have remain unresolved. Here, we offer structural insights on these issues by carrying out a detailed investigation using a set of complementary tools involving temperature-dependent x-ray powder diffraction, neutron powder diffraction, dielectric, ferroelectric, piezoelectric, and thermally induced depoling current measurements. We show that onset of thermal depoling in NBT $(x=0)$ well below its depolarization temperature is caused by abrupt reduction of intrinsic polarization in the ferroelectric $R3c$ phase, triggered by the appearance of the $P4bm$ phase. Our study suggests that partial conversion of the Cc average structure to $R3c$ in unpoled NBT-BT at $x\ensuremath{\sim}0.03$ (more precisely in the range $0.03\ensuremath{\le}x\ensuremath{\le}0.05$) is catalyzed by the appearance of $P4bm$ phase. The overlap of ${T}_{d}$ and ${T}_{2}$ for this composition range is correlated with the collapse of the tetragonality of the $P4bm$ phase and significantly reduced kinetic barrier associated with the $R3c\ensuremath{\rightarrow}P4bm$ transformation. We show that the abrupt crossover between ${T}_{d}$ and ${T}_{2}$ at $x=0.06$ is due to takeover of the thermal depoling process by an emergent tetragonal $(P4mm)$-like ferroelectric distortion. We present updated phase diagrams of poled and unpoled specimens which highlight all the subtle details needed to explain the temperature-dependent properties of this complex piezoelectric alloy system.

We studied the structural evolution and cycling behavior of TiNb

Fe

Journal of alloys and compounds 858, 157742 (2021). doi:10.1016/j.jallcom.2020.157742, Novel bismuth niobates Bi1.5Mg1–xNaxNb1.5O7–δ and Bi1.5Mg0.9–xNaxNb1.5O7–δ (0 ≤ x ≤ 0.50) with the pyrochlore structure have been investigated experimentally and theoretically. The compounds were synthesized by an organic-inorganic precursors combustion method. The pyrochlore structure was formed at x = 0.10; 0.25 for cation completed and 0.25; 0.40 for cation deficient compositions, respectively. From differential scanning calorimetry (DSC) and thermogravimetry (TG), the thermal stability of the compounds up to their melting points (1250–1270 °C) was concluded. The single-crystal forms of the pyrochlores can be easily obtained from the melts. Structural characterization was performed using a Rietveld refinement against X-ray diffraction (XRD) as well as the simultaneous refinement using high resolution neutron powder diffraction (NPD) and synchrotron X-ray diffraction (SXRD) data. According to the results, the displacements of A (from 16c to 96g) and O′ (from 8a to 32e or 96g) atoms from ideal pyrochlore sites as well as the Na atoms distribution in the bismuth sub-structure, and the Mg atoms in the niobium sub-structure were determined. The same distribution of dopants in the structure was proven by DFT-PBE simulations of crystal structure and thermodynamic properties. The most preferable (Bi1.5Mg0.5)(Nb1.5Mg0.5)O7 and (Bi1.5Na0.5)(Nb1.5Mg0.5)O7 models were predicted. Both calculated/experimental direct band gap values were found to decrease from Mg-doping (3.20/3.21 eV) to Mg, Na-codoping (3.16/3.15 eV). The electrical properties were investigated by impedance spectroscopy method in air, in oxygen, and humid atmospheres in the temperature range of 25–750 °C. The typical dielectric behavior of the compounds up to 200 °C was detected. With the Na content rising the increasing of ε′ values from 86 (x = 0) to 145 (x = 0.4) was revealed at the same tanδ ≈ 0.0025 (1 MHz, 25 °C). Calculated temperature coefficients of capacitance (TCC) values varied from −594 to −724 ppm/°C (25–280 °C). Besides, contribution from electronic conductivity (T < 360 °C), proton transport below 360–400 °C as well as the ionic (oxygen) conductivity at T > 400 °C were observed., Published by Elsevier, Lausanne

Journal of physics / Condensed matter 33, 105901 (2021). doi:10.1088/1361-648X/abcdb0, Diffraction and imaging using x-rays and neutrons are widely utilized in different fields ofengineering, biology, chemistry and/or materials science. The additional information gainedfrom the diffraction signal by x-ray diffraction and computed tomography (XRD-CT) can givethis method a distinct advantage in materials science applications compared to classicaltomography. Its active development over the last decade revealed structural details in anon-destructive way with unprecedented sensitivity. In the current contribution an attempt toadopt the well-established XRD-CT technique for neutron diffraction computed tomography(ND-CT) is reported. A specially designed ‘phantom’, an object displaying adaptable contrastsufficient for both XRD-CT and ND-CT, was used for method validation. The feasibility ofND-CT is demonstrated, and it is also shown that the ND-CT technique is capable to provide anon-destructive view into the interior of the ‘phantom’ delivering structural informationconsistent with a reference XRD-CT experiment., Published by IOP Publ., Bristol

ACS applied materials & interfaces 13(5), 6309-6321 (2021). doi:10.1021/acsami.0c20905, We studied the structural evolution and cycling behavior of TiNb$_2$O$_7$ (TNO) as a cathode in a nonaqueous hybrid dual-salt Mg–Li battery. A very high fraction of pseudocapacitive contribution to the overall specific capacity makes the material suitable for ultrafast operation in a hybrid battery, composed of a Mg-metal anode, and a dual-salt APC–LiCl electrolyte with Li and Mg cations. Theoretical calculations show that Li intercalation is predominant over Mg intercalation into the TNO in a dual-salt electrolyte with Mg$^{2+}$ and Li$^+$, while experimentally up to 20% Mg cointercalation was observed after battery discharge. In hybrid Mg–Li batteries, TNO shows capacities which are about 40 mA h g$^{–1}$ lower than in single-ion Li batteries at current densities of up to 1.2 A g$^{–1}$. This is likely due to a partial Mg cointercalation or/and location of Li cations on alternative crystallographic sites in the TNO structure in comparison to the Li-intercalation process in Li batteries. Generally, hybrid Mg–Li cells show a markedly superior applicability for a very prolonged operation (above 1000 cycles) with 100% Coulombic efficiency and a capacity retention higher than 95% in comparison to conventional Li batteries with TNO after being cycled either under a low (7.75 mA g$^{–1}$) or high (1.55 A g$^{–1}$) current density. The better long-term behavior of the hybrid Mg–Li batteries with TNO is especially pronounced at 60 °C. The reasons for this are an appropriate cathode electrolyte interface containing MgCl$_2$ species and a superior performance of the Mg anode in APC–LiCl electrolytes with a dendrite-free, fast Mg deposition/stripping. This stable interface stands in contrast to the anode electrolyte interface in Li batteries with a Li anode in conventional carbonate-containing electrolytes, which is prone to dendrite formation, thus leading to a battery shortcut., Published by Soc., Washington, DC

In the scientific article the need to develop organic production as an important priority for the development of the state food industry are emphasized. A comparative description of European countries with similar natural development potential of the organic sector to Ukraine is made, the volume of the domestic market of organic products in Ukraine is analyzed. The research revealed that Ukraine is a world leader in the production of organic honey, occupies a leading position in the area of certified land, and mainly specializes in the cultivation of grain and oilseeds. It is determined that the key element in the process of development of organic production in Ukraine was the adoption of the Law of Ukraine «On basic principles and requirements for organic production, circulation and labeling of organic products». The law regulates the basic principles and requirements for state organic production, circulation and labeling of organic products, principles of legal regulation of organic production, circulation of organic products and functioning of the organic products market, legal bases of central executive bodies, organic market participants and public policy in these areas. It is proved that an important step towards the development of state organic production is the adoption by the Government of the «Procedure for certification of organic production and circulation of organic products», which was developed taking into account the requirements of EU legislation. The document defines the rules of certification of organic production and circulation of organic products, as well as the procedure for issuing a certificate, its duplicate and form. Given that Ukraine is a leading supplier of organic products to foreign markets, as evidenced by the above data, the introduction of its own certification system will enhance Ukraine’s image in the world trade arena. In addition, it will contribute to the sustainable development of the state organic sector, increase the transparency of production and saturate the state market with organic products. The author notes the first important steps in the development of state organic production, based on which the main problems of such development are identified, which will form an effective infrastructure of the organic market, ensure both environmental and food security of agriculture as a whole.

Anionic redox is a double-edged sword for Li-ion cathodes because it offers a transformational increase in energy density that is also negated by several detrimental drawbacks to its practical implementation. Among them, voltage hysteresis is the most troublesome because its origin is still unclear and under debate. Herein, we tackle this issue by designing a prototypical Li-rich cation-disordered rock-salt compound Li

The complex interplay of local disorder with the structure and dynamics and their role in enhancing the electromechanical response makes relaxor ferroelectric materials fascinating both from the scientific and technological standpoints. It is generally believed that in chemically disordered ferroelectric solid solutions, the normal ferroelectric state gradually yields to a relaxor ground state on increasing the concentration of localized (point-defect-like) random-field centers. That a different kind of process can spontaneously stabilize a relaxor ground state is less known, especially in the family of ferroelectric perovskites. We demonstrate the occurrence of this less-known phenomenon in $(1\ensuremath{-}x){\mathrm{K}}_{0.5}{\mathrm{Bi}}_{0.5}\mathrm{Ti}{\mathrm{O}}_{3}\text{\ensuremath{-}}(x){\mathrm{Na}}_{0.5}{\mathrm{Bi}}_{0.5}\mathrm{Ti}{\mathrm{O}}_{3}[(1\ensuremath{-}x)\mathrm{KBT}\ensuremath{-}(x)\mathrm{NBT}]$. Unlike the gradual evolution common to most ferroelectric solid solutions, KBT-xNBT exhibits an abrupt crossover from a normal ferroelectric ground state to a full-blown relaxor ground state for $xg0.58$. We show that this abrupt crossover to the relaxor state is caused by stabilization of an incommensurate-like/highly disordered $M$-point ferroelastic distortion in the ergodic/paraelectric temperature regime. The abrupt crossover manifests as composition driven anomalous changes in several important properties such as dielectric response, electromechanical properties, tetragonality, and coercive field, electrostrain, and mimics a scenario often encountered in composition driven interferroelectric transformations.

Colleges and universities in the United States and in other countries are admitting and educating an increasing number of international students. This trend creates both challenges and opportunitie...