Densification effect of perovskite-type Li3xLa2/3-xTiO3 solid-state electrolytes for energy storage applications.

This study focuses on developing a perovskite Li 3x La 2/3-x TiO 3 (LLTO) electrolyte using a simple and effective sol-gel technique. This study aims to enable the hopping of lithium ions in lanthanum sites, which enhances the overall ionic conductivity of the material. By employing an ion conduction mechanism, we investigated the conductivity of powdered and pelletized (dense) LLTO materials. Dense-LLTO exhibits a higher grain ionic conductivity of σ = 1.32 × 10−4 S/cm at room temperature, whereas powdered-LLTO gives a significantly lower conductivity. This significant difference in conductivity can be attributed to the closely packed arrangement of ions in the dense-LLTO structure, which minimizes the evaporation of lithium (Li) in lanthanum (La) sites and promotes ion mobility. Therefore, the thermal treatment process plays a crucial role in facilitating the ion(s) movement and its impact on the ionic conductivity of LLTO, which is mainly influenced by the lithium content. To further evaluate the practical application of LLTO as a solid electrolyte, we constructed a solid-state device with LiFePO 4 /LLTO/AC. The LLTO electrolyte is sandwiched between the activated carbon and LiFePO 4 electrodes. This device exhibits an impressive energy density, achieving 2.42 Wh/kg and a power density of 192 W/kg. Moreover, the device demonstrates better rate capability, allowing for efficient charge and discharge processes. Remarkably, the cyclic stability analysis revealed a retention rate of 92 % over 10,000 cycles, indicating the robustness and durability of the LLTO-based solid-state battery system. These findings highlight the potential of LLTO as a promising solid electrolyte material for advanced energy storage devices. The sol-gel synthesis method provides a simple and effective approach for obtaining high-performance LLTO electrolytes. The enhanced ionic conductivity and excellent electrochemical performance of the solid-state LiFePO 4 /LLTO/AC device demonstrate the feasibility and prospects of LLTO-based batteries in practical applications, offering improved energy density, power density, and long-term cycling stability. [ABSTRACT FROM AUTHOR]