Enhanced Ionic Conductivity of Fluoride-Doped LiTi₂(PO₄)₃ as Solid Electrolyte of Lithium-Ion Battery

Abstract

In this study, LiTi2(PO4)3 (LTP) was synthesized by the addition of lithium fluoride (LiF) of 0 %, 5 %, and 10 wt.%. A wet solid-state reaction method is applied by mixing Li2CO3, TiO2, and NH4H2PO4 into a ball mill, then calcined at 900o C for 12 hr. XRD pattern of Fluoride-doped LTP is indexed and found in two phases. First is the Nasicon phase (LiTi2(PO4)3) with rhombohedral structure, and second, the Olivine phase (LiTiPO5) with orthorhombic structure at the addition of 5 % and 10 wt. % of LiF. The higher LiF decreases the cell volume while the crystallite size, particle size, and material density increase. The morphology of the Fluoride-doped LTP is increasingly homogeneous and more rectangle-shape. LTP 2, adding 10 wt. % of LiF, has high ionic conductivity at 4.77 10-4 S cm-1 as a promising candidate material for solid-electrolyte of lithium-ion battery.