The glasses with the composition of 37.5Li2O–(25−x)Fe2O3–xNb2O5–37.5P2O5 (mol%) (x = 5, 10, 15) were prepared, and it was found that the addition of Nb2O5 was effective for the glass formation in the lithium iron phosphate system. The glass–ceramics consisting of NaSiCON-type Li3Fe2(PO4)3 crystals with an orthorhombic structure were developed through conventional crystallization in an electric furnace, showing electrical conductivities of 3 x 10−6S/cm at room temperature and the activation energies of 0.48eV (x = 5) and 0.51eV (x = 10) for Li+ ion conduction at 30 to 200C. A continuous wave Nd:YAG laser (wavelength: 1064nm) with powers of 0.14–0.30W and a scanning speed of 10μm/s was irradiated onto the surface of the glasses, and the formation of Li3Fe2(PO4)3 crystals was confirmed from X-ray diffraction analyses and micro-Raman scattering spectra. The crystallization of the precursor glasses was considered as new route for the fabrication of Li3Fe2(PO4)3 crystals being candidates for use as electrolyte materials in Li ion secondary batteries.

Lithium Ion Conductive Glass–Ceramics with Li3Fe2(PO4)3 and YAG Laser-Induced Local Crystallization in Lithium Iron Phosphate Glasses. K.Nagamine, K.Hirose, T.Honma, T.Komatsu: Solid State Ionics, 2008, 179[13-14], 508-15