The Impact of Boron Compounds on the Structure and Ionic Conductivity of LATP Solid Electrolytes

The increasing demand for safe and high-energy-density battery systems has led to intense research into solid electrolytes for rechargeable batteries. One of these solid electrolytes is the NASICON-type Li_1+xAl_xTi_2-x(PO₄)₃ (LATP) material. In this study, different boron compounds (10% B₂O₃ doped, 10% H₃BO₃ doped, and 5% B₂O₃ + 5% H₃BO₃ doped) were doped at total 10 wt.% into the Ti⁴⁺ sites of an LATP solid electrolyte to investigate the structural properties and ionic conductivity of solid electrolytes using the solid-state synthesis method. Characterization of the synthesized samples was conducted using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). The XRD patterns of the boron-doped LATP (LABTP) samples show that the samples have a rhombohedral phase with space group R3¯c together and low amounts of impurity phases. While all the LABTP samples exhibited similar ionic conductivity values of around 10^-4 S cm^-1, the LABTP2 sample doped with 10 wt.% H₃BO₃ demonstrated the highest ionic conductivity. These findings suggest that varying B³⁺ ion doping strategies in LATP can significantly advance the development of solid electrolytes for all-solid-state lithium-ion batteries.