Cubic phase Li7La3Zr2O12(LLZO),a member of the Li–Garnet family,is a promising solid electrolyte and has been widely studied in recent years.However,LLZO samples prepared via conventional ambient air sintering report...Cubic phase Li7La3Zr2O12(LLZO),a member of the Li–Garnet family,is a promising solid electrolyte and has been widely studied in recent years.However,LLZO samples prepared via conventional ambient air sintering reported in the published literature often contain large grains with lower than desired(<94%)relative density.In this study,a non-contact method of co-firing with mother powder method is proposed to prepare high-quality Ta-doped LLZO–MgO composite ceramics.By sintering at 1150℃for 5 h,the ceramics can reach relative density of 98.2%,conductivity of 5.17×10^-4 S cm^-1 at 25℃and fracture strength of 150 MPa.The sintered samples have uniform fine-grained microstructure and high critical current densities of 0.75–0.95 mA cm-2 at room temperature in Li–Li symmetry cell with Au modification.In addition,systematic sintering experiments and characterizations are conducted to explore the function of MgO in inhibiting the Ta-LLZO grain growth and its existing form inside the composite ceramics.展开更多
Cubic Li-Garnet Li_(7)La_(3)Zr_(2)O_(12)(c-LLZO)is one of the promising solid-state electrolyte candidates for the next generation high safety solid-state batteries.However,preparing the electrolyte has many challenge...Cubic Li-Garnet Li_(7)La_(3)Zr_(2)O_(12)(c-LLZO)is one of the promising solid-state electrolyte candidates for the next generation high safety solid-state batteries.However,preparing the electrolyte has many challenges.Li-loss during high temperature sintering is one of them.Mother powder with the same component of green garnet pellets is often used to co-fire with the pellets to compensate the Li-loss.Due to the high weight ratio of rare earth element La and non-recyclability of mother powder,it is worthy to explore low-cost mother powders to replace them.In this paper,low cost compounds such as Li_(5)AlO_(4),Li_(2)TiO_(3),Li_(2)SiO_(3),Li4SiO_(4)and(Li_(2)O)x-(ZrO_(2))_(1-x)(x=0.6-0.8)are investigated for substitution of the mother powder for compensating Li-loss during the sintering of LLZO.Dense Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)samples have been prepared by sintering with(Li_(2)O)0.733(ZrO_(2))0.267 powder at 1150℃for 5 h with the relative density of 95%and conductivity of 5.7×10^(-4)S cm^(-1)at 25℃,which show same performance with LLZTO ceramics sintered with LLZO mother powder.展开更多
基金financially supported by the National Key R&D Program of China under Grant No.2018YFB0905400,Corning Incorporatedthe National Natural Science Foundation of China under Grant No.51772315,No.51432010
文摘Cubic phase Li7La3Zr2O12(LLZO),a member of the Li–Garnet family,is a promising solid electrolyte and has been widely studied in recent years.However,LLZO samples prepared via conventional ambient air sintering reported in the published literature often contain large grains with lower than desired(<94%)relative density.In this study,a non-contact method of co-firing with mother powder method is proposed to prepare high-quality Ta-doped LLZO–MgO composite ceramics.By sintering at 1150℃for 5 h,the ceramics can reach relative density of 98.2%,conductivity of 5.17×10^-4 S cm^-1 at 25℃and fracture strength of 150 MPa.The sintered samples have uniform fine-grained microstructure and high critical current densities of 0.75–0.95 mA cm-2 at room temperature in Li–Li symmetry cell with Au modification.In addition,systematic sintering experiments and characterizations are conducted to explore the function of MgO in inhibiting the Ta-LLZO grain growth and its existing form inside the composite ceramics.
基金This work was financially supported by the National Key R&D Program of China under Grant No.2018YFB0905400Corning Incorporated,the National Natural Science Foundation of China under Grant No.51772315,No.51432010Key Fundamental Research Project from Science and Technology Commission of Shanghai Municipality(14JC1493000).
文摘Cubic Li-Garnet Li_(7)La_(3)Zr_(2)O_(12)(c-LLZO)is one of the promising solid-state electrolyte candidates for the next generation high safety solid-state batteries.However,preparing the electrolyte has many challenges.Li-loss during high temperature sintering is one of them.Mother powder with the same component of green garnet pellets is often used to co-fire with the pellets to compensate the Li-loss.Due to the high weight ratio of rare earth element La and non-recyclability of mother powder,it is worthy to explore low-cost mother powders to replace them.In this paper,low cost compounds such as Li_(5)AlO_(4),Li_(2)TiO_(3),Li_(2)SiO_(3),Li4SiO_(4)and(Li_(2)O)x-(ZrO_(2))_(1-x)(x=0.6-0.8)are investigated for substitution of the mother powder for compensating Li-loss during the sintering of LLZO.Dense Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)samples have been prepared by sintering with(Li_(2)O)0.733(ZrO_(2))0.267 powder at 1150℃for 5 h with the relative density of 95%and conductivity of 5.7×10^(-4)S cm^(-1)at 25℃,which show same performance with LLZTO ceramics sintered with LLZO mother powder.
