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Finding the optimum material with improved properties for a given application is challenging because data acquisition in materials science and chemistry is time consuming and expensive. Therefore, dealing with small datasets is a reality in chemistry, whether the data are obtained from synthesis or computational experiments. In this work, we propose a new artificial intelligence method based on active learning (AL) to guide new experiments with as little data as possible, for optimum experimental design. The AL method is applied to AB[O.sub.3] perovskites, where a descriptor based on atomic properties was developed. Several regressor algorithms were employed: artificial neural network, Gaussian process, and support vector regressor. The developed AL method was applied in the experimental design of two important materials: non-stoichiometric perovskites ([Ba.sub.(1-x)][A.sub.x][Ti.sub.(1-y)][B.sub.y[O.sub.3]) due to substituting ionic sites with different concentrations and elements (A = Ca, Sr, Cd; B =Zr, Sn, Hf), aiming at the maximization of the energy storage density, and stoichiometric AB[O.sub.3] perovskites where different elements are changed in the A and B sites for the minimization of the formation energy. AL for experimental design is implemented in the machine learning agent for chemistry and design (MLChem4D) software, which has the potential to be applied in inorganic and organic synthesis (e.g., search for the optimum concentrations, catalysts, reactants, temperatures, and pH to improve the yield) and materials science (e.g., search the periodic table for the proper elements and their concentrations to improve the materials properties). The latter marks the first MLChem4D application for the design of perovskites. Key words: materials, perovskites, machine learning, active learning, design of experiment, transition metal oxides, 1. Introduction Gaining insight about the next experimental conditions to find new materials with improved properties (such as bandgap, mechanical properties, formation energy, convex hull energy, and energy storage density) [...]

Li metal batteries with garnet‐type solid electrolytes have the potential to increase specific energy and power densities of current Li‐ion batteries. Li metal batteries have been hampered by the poor wettability of solid electrolyte with elemental lithium. Here, to resolve the solid garnet electrolyte/Li interface issue, a scalable, cost‐effective, and efficient surfactant‐assisted wet‐chemical strategy is developed. A ZnF2 interlayer coating is applied on Ba and Ta ‐co‐doped Li7La2.75Ba0.25Zr1.75Ta0.25O12 that formed LiF and Li‐Zn alloy upon contact with molten Li. Conformal contact applying a homogenous surfactant‐assisted ZnF2 coating reduced the interfacial resistance from 87 to 15.5 Ω cm2 which enhanced critical current density to a record high value of 5 mA cm−2 at room temperature. Dense and Li2CO3 free garnet solid electrolyte assisted in achieving long‐term stability for 1000 cycles at 1 mA cm−2. Interface stabilized Li/ZnF2‐ solid electrolyte/liquid electrolyte/LiFePO4 cell displayed a 90% capacity retention over 800 cycles at 0.2 C, with Coulombic efficiency of 99% as well as excellent cycle stability at 1 C, with ≈91% of capacity retention for 500 cycles. Using a new design principle for Li anode interfaces, next‐generation power‐intensive and stable solid‐state Li metal batteries can be developed. [ABSTRACT FROM AUTHOR]

Current lithium-ion batteries have been widely used in portable electronic devices, electric vehicles, and peak power demand. However, the organic liquid electrolytes used in the lithium-ion battery are flammable and not stable in contact with elemental lithium and at a higher voltage. To eliminate the safety and instability issues, solid-state (ceramic) electrolytes have attracted enormous interest worldwide, owing to their thermal and high voltage stability. Among all the solid-state electrolytes known today, the Li-stuffed garnet is one of the most promising electrolytes due to its physical and chemical properties such as high total Li-ion conductivity at room temperature, chemical stability with elemental lithium and high voltage lithium cathodes, and high electrochemical stability window (6 V vs. [Li.sup.+]/Li). In this short review, we provide an overview of Li-stuffed garnet electrolytes with a focus on their structure, ionic conductivity, transport mechanism, chemical stability, and battery applications. Key words: solid electrolytes, Li-rich garnets, ionic conductivity, chemical stability, interface, solid-state Li batteries. Les batteries au lithium-ion actuelles sont largement utilisées dans les appareils électroniques portables et les véhicules électriques ainsi que dans des applications à demande de puissance maximale. Cependant, les électrolytes liquides organiques utilisés dans les batteries au lithium-ion sont inflammables et ne sont pas stables au contact du lithium métal et à des tensions plus élevées. En vue d'éliminer les problèmes de sécurité et de in stabilité, les électrolytes solides (céramiques) ont suscité un intérêt énorme dans le monde entier, en raison de leur stabilité thermique et à haute tension. Parmi tous les électrolytes solides connus à ce jour, le grenat rempli de lithium est l'un des électrolytes les plus prometteurs en raison de ses propriétés physiques et chimiques, notamment la conductivité ionique du lithium total élevée à température ambiante, la stabilité chimique en présence de lithium métal et de cathodes au lithium à haute tension, ainsi que la fenêtre de stabilité électrochimique élevée (6 V vs [Li.sup.+]/Li). Dans ce bref article de synthèse, nous présentons un aperçu des électrolytes à base de grenat rempli de lithium, en nous intéressant à leur structure, à leur conductivité ionique, à leur mécanisme de transport, à leur stabilité chimique et à leurs applications aux batteries. [Traduit par la Rédaction] Mots-clés : électrolytes solides au lithium-ion, grenats riches en Li, conductivité ionique, stabilité chimique, interface, batteries à électrolyte solide au lithium., Introduction All-solid-state batteries (ASSBs) containing a Li metal anode are projected as the ultimate battery technology due to their higher energy density and better safety than the present Li-ion batteries [...]

Development and application of large‐scale energy storage systems are surging due to the increasing proportion of intermittent renewable energy sources in the global energy mix. Redox flow batteries are prime candidates for large‐scale energy storage due to their modular design and scalability, flexible operation, and ability to decouple energy and power. To date, several different redox couples are exploited in redox‐flow batteries; some are already commercialized. This battery technology is facing a lot of challenges in the science, engineering, and economic front. Issues plaguing flow batteries are low energy density, high overall cost, poor stability of electrolytes, shifting of solvent from anolyte to catholyte while using cation exchange membrane, reverse flow with anion exchange membrane, and corrosion of graphite felt in the catholyte side. Significant research efforts are ongoing to address these challenges. This comprehensive and critical review summarizes the recent progress in electrolyte technologies, including electrochemical performance and stability, strategies to enhance the energy and power densities and, in the end, the levelized and life‐cycle cost of these batteries analyzed. A comprehensive outlook on this technology with respect to practical energy storage applications is also provided. [ABSTRACT FROM AUTHOR]

Garnet‐type Li7La3Zr2O12 electrolytes have garnered significant attention as promising solid‐state electrolyte candidates in all‐solid‐state lithium batteries (ASSLBs). However, its susceptibility to forming Li2CO3 upon atmospheric exposure leads to performance degradation, limiting its application. This study introduces a co‐doping strategy of Mg and Ta to enhance the properties of garnet electrolytes. Pure cubic Mg and Ta‐doped LLZO electrolytes are successfully synthesized using the solid‐state reaction method. Experimental results, coupled with density functional theory (DFT) calculation, reveal that Mg2+ doping occurs primarily at the La site (24c). This substitution, given the substantial disparity in ionic radii between Mg2+ and La3+, effectively narrows the transport bottleneck for Li‐ions, resulting in a decreased ionic conductivity and an increased activation energy. Li6.6La2.8Mg0.2Zr1.4Ta0.6O12 exhibits a relative density of ≈92.6%, demonstrating outstanding performance with a room temperature ionic conductivity of 4.31 × 10−4 S cm−1 and low electronic conductivity of 2.48 × 10−8 S cm−1. Notably, after 4 months of atmospheric exposure, its ionic conductivity decreased to ≈78% of the initial value, attributable to Li2CO3 formation. Furthermore, the material demonstrated exceptional long‐term cycle stability over 1000 h at a current density of 0.1 mA cm−2 at 25 °C, indicating effective suppression of Li dendrite formation. [ABSTRACT FROM AUTHOR]