The rapid development of portable electronic devices and the efforts to find alternatives to fossil fuels have triggered the rapid development of battery technology. The conventional lithium-ion batteries have reached a high degree of sophistication. However, improvements related to specific capacity, charge rate, safety and sustainability are still required. Solid state batteries try to answer these demands by replacing the organic electrolyte of the standard battery with a solid (crystalline, but also polymer and hybrid) electrolyte. One of the most promising solid electrolytes is Li_3xLa_2/3−xTiO₃ (LLTO). The material nevertheless presents a set of key challenges that must be resolved before it can be used for commercial applications. This review discusses the synthesis methods, the crystallographic and the ionic conduction properties of LLTO and the main limitations encountered through a number of selected studies on this material.

Thermal protection systems (TPS) for aerospace industry require the use of coatings made from ultra-high temperature ceramics (UHTCs), a class of materials based on oxides, nitrides, carbides and borides of transitional metals. Yttria-doped zirconia is the actual “gold standard” for aerospace coatings but the high temperature phase transitions limit its use in developing a new generation of TPS. Rare earth zirconia pyrochlores Ln₂Zr₂O₇ (Ln = La, Nd, Sm, Gd, Yb) emerged as future candidates for high temperature coatings due to their high thermal stability on a large temperature range. Here, we review the crystalline structures’ electronic and thermal properties of these materials, the main methods proposed for their synthesis, their advantages and disadvantages. The use of mixed rare earths as dopant for zirconia ceramics is presented further. Finally, the potential applications as thermal barrier coatings (TBCs) are presented.

Lithium lanthanum titanate (LLTO) is a very promising material due to its ability to conduct lithium ions. It has many potential applications in the field of lithium batteries and sensors. Typical synthesis methods include solid-state reaction and sol–gel synthesis. We report a novel solvothermal synthesis method that produces almost single-phase LLTO samples at significantly reduced costs. The samples thus obtained were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrical impedance spectroscopy (EIS), and chemical analysis. The results obtained for the newly synthesized samples were compared with results obtained from samples prepared using the solid-state reaction method. The XRD data show the formation of orthorhombic LLTO for the solvothermal synthesis, tetragonal LLTO for the hydrothermal synthesis, and cubic LLTO for the solid-state reaction. Additionally, XRD showed that the solid-state reaction of LLTO is a multi-stage process in which intermediary compounds such as La₂Ti₂O₇ are formed. The bulk ionic conductivity of the LLTO samples produced through the solvothermal and hydrothermal processes is estimated at 10⁻⁴ S/cm, and the grain boundary conductivity is estimated at 10⁻⁶ S/cm.

This study investigates the application of robocasting technology for fabricating high-density yttria-stabilized zirconia (8YSZ) electrolytes used in solid oxide fuel cells (SOFCs). The primary goal is to overcome the limitations of traditional manufacturing techniques, such as low density and poor microstructural control. Using a combination of hydrothermal synthesis, rheological testing, and robocasting, we achieved dense 8YSZ structures (over 95% density) with minimal porosity. The fabricated electrolytes underwent sintering and debinding processes, with thermal treatment profiles optimized for structural integrity. A microstructural analysis through SEM and XRD confirmed the formation of stable crystalline phase. This research opens new avenues for the use of additive manufacturing in electrochemical applications, particularly for producing complex ceramic components with superior characteristics.