Composition solid electrolytes (1 − x)LiClO₄-xMgO are synthesized and their physicochemical properties are studied. According to the data of differential scanning calorimetry, for sufficiently high oxide concentrations, all lithium perchlorate is present in the composite in the amorphous state. Impedance spectroscopic studies demonstrate that the conductivity of composites passes through a maximum at x = 0.8−0.9, reaching ∼10⁻² S/cm at 200°C. Based on voltammetric characteristics, it is shown that the voltage of electrochemical decomposition of composites in vacuum does not exceed 3.5–4.0 V, decreasing to 1.8–2.0 V in humid atmosphere. The conductivity of studied composites in vacuum may apparently be attributed to lithium ions, and these solid electrolytes can be used in solid-state electrochemical lithium cells.

Composite solid electrolytes (C₄H₉)₄NBF₄–Al₂O₃ are synthesized in a wide range of composition. Their thermal, structural, and conducting properties are studied. The conductivity of the composites passes through a maximum at x ~ 0.9 and reaches 7.2 × 10^–4 S/cm at 150°C for the 0.1(C₄H₉)₄NBF₄–0.9Al₂O₃ composite. The absence of thermal effect at the melting temperature of the ionic salt and the absence of peaks of tetrabutylammonium tetrafluoroborate in the diffraction pattern for a composite, which exhibits a high ionic conductivity, indicate that at x ≥ 0.9, (C₄H₉)₄NBF₄ is in the amorphous state, and ionic transfer occurs along the ionic salt/oxide interface.

The study demonstrates that the introduction of the electrochemically inactive dielectric additive Li₂TiO₃ to LTO results in a strong decrease in the grain boundary resistance of LTO-Li₂TiO₃ (LTC) composites at a low concentration of Li₂TiO₃. With the increase in the concentration of Li₂TiO₃ in LTC composites, the grain boundary resistance goes through a minimum and increases again due to the growth of the insulation layer of small Li₂TiO₃ particles around LTO grains. For LTO-TiO₂ (LTT) composites, a similar effect was observed, albeit not as strong. It was found that LTC composites at low concentration of Li₂TiO₃ have unusually high charge–discharge capacity exceeding the theoretical value for pure LTO. This effect is likely to be caused by the occurrence of the electrochemical activity of Li₂TiO₃ in the vicinity of the interfaces between LTO and Li₂TiO₃. The increase in the capacity may be qualitatively described in terms of the model of two-phase composite in which there is the interface layer with a high capacity. Contrasting with LTC composites, in LTT composites, no capacity enhancement was observed, which was likely due to a noticeable difference in crystal structures of LTO and TiO₂ preventing the formation of coherent interfaces.