Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-therm...Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4＋ and A13＋ with PO43- Well crystallized Lil.3Alo.3Til.7（PO4）3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7（PO4）a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.展开更多
Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosit...Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosity play an important role.In a presence of more than one secondary phase and pores,image analysis must tackle the difficulties about distinguishing between these microstructural features.In this study,we study the phase evolution of LATP ceramics sintered at temperatures between 950 and 1100℃by image segmentation based on energy-dispersive X-ray spectroscopy(EDS)elemental maps combined with quantitative analysis of LATP grains.We found aluminum phosphate(AlPO4)and another phosphate phase((Lix)PyOz).The amount of these phases changes with sintering temperature.First,since the grains act as an aluminum source for AlPO4 formation,the aluminum content in the LATP grains decreases.Second,the amount of secondary phase changes from more(Lix)PyOz at 950℃to mainly AlPO4 at 1100℃sintering temperature.We also used scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)to study the evolution of the LATP grains and AlPO4,and LATP grain size increases with sintering temperature.In addition,transmission electron microscopy(TEM)was used for the determination of grain boundary width and to identify the amorphous structure of AlPO4.展开更多
文摘Lithium-ion conductor Liz.3Alo.3Ti1.7（P04）3 with an ultrapure NASICON-type phase is syn- thesized by a 1,2-propylene glycol （1,2-PG）-assisted sol-gel method and characterized by differential thermal analysis-thermo gravimetric analysis, X-ray diffraction, scanning elec- tron microscopy, electrochemical impedance spectroscopy, and chronoamperornetry test. Due to the use of 1,2-PG, a homogeneous and light yellow transparent precursor solu- tion is obtained without the precipitation of Ti4＋ and A13＋ with PO43- Well crystallized Lil.3Alo.3Til.7（PO4）3 can be prepared at much lower temperatures from 850 ~C to 950 ~C within a shorter synthesis time compared with that prepared at a temperature above 1000 ~C by a conventional solid-state reaction method. The lithium ionic conductivity of the sintered pellets is up to 0.3 mS/cm at 50 ℃ with an activation energy as low as 36.6 k J/tool for the specimen pre-sintered at 700 ℃ and sintered at 850 ℃. The high conductivity, good chemi- cal stability and easy fabrication of the Li1.3Al0.3Ti1.7（PO4）a provide a promising candidate as solid electrolyte for all-solid-state Li-ion rechargeable batteries.
文摘Lithium aluminum titanium phosphate(LATP)is one of the materials under consideration as an electrolyte in future all-solid-state lithium-ion batteries.In ceramic processing,the presence of secondary phases and porosity play an important role.In a presence of more than one secondary phase and pores,image analysis must tackle the difficulties about distinguishing between these microstructural features.In this study,we study the phase evolution of LATP ceramics sintered at temperatures between 950 and 1100℃by image segmentation based on energy-dispersive X-ray spectroscopy(EDS)elemental maps combined with quantitative analysis of LATP grains.We found aluminum phosphate(AlPO4)and another phosphate phase((Lix)PyOz).The amount of these phases changes with sintering temperature.First,since the grains act as an aluminum source for AlPO4 formation,the aluminum content in the LATP grains decreases.Second,the amount of secondary phase changes from more(Lix)PyOz at 950℃to mainly AlPO4 at 1100℃sintering temperature.We also used scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)to study the evolution of the LATP grains and AlPO4,and LATP grain size increases with sintering temperature.In addition,transmission electron microscopy(TEM)was used for the determination of grain boundary width and to identify the amorphous structure of AlPO4.
