Laser-induced modification and external pressureless joining Na2FeP2O7 on solid electrolyte

Abstract

Na2FeP2O7 (NFP) ceramics show potential application as the active material for sodium ion batteries. In this study, NFP ceramics were irradiated with infrared laser light with a wavelength of 1 µm. Fe2+ ions allowing local heating and resulting in instantaneous melting and rapid cooling for glass formation. The results of differential thermal analysis and X-ray diffraction suggest that the laser-irradiated part is vitrified and that rapid cooling is achieved to prevent recrystallization. It was possible to form a molten pattern withan output of 0.22 W and a scanning rate of up to 3mm/s of laser light. Irradiation of laser light on NFP powder on NASICON-type Na3Zr2Si2PO12 solid electrolyte ceramic enabled the formation of a dense glassy NFP phase of several tenth-micrometer depths on solid electrolyte ceramic. This technique is a promising process mainly for developing an oxide-based all-solid-state battery because the contact interface can form instantaneously without external mechanical pressure.