Garnet related lithium ion conductor processed by spark plasma sintering for all solid state batteries

Abstract: Oxide based all solid state battery (ASSB) system requires a highly enhanced cell assembly technology due to the sintering issue although various inorganic based lithium ion conductors have been proposed and tried to adopt battery system. In present research, compatibility of Li-La-(Zr-Ta)-O garnet related lithium ion conductors for ASSB system processed by spark plasma sintering (SPS) are reported, and the challenges are discussed with respect to the material and process issues. Li7La3Zr1.5Ta0.5O12 processed by SPS shows the high ionic conductivity of 1.35x10-3 and 1.23x10-2 at 25 oC and 80 oC, respectively, and it also shows the structural stability, which is one of the critical issues for garnet structured material, under severe SPS process condition. ASSB with a surface capacity of 0.2 mAhcm-2 at 80 oC is assembled using Li4Ti5O12-Li7-xLa3Zr1.5Ta0.5O12-d composite electrode by SPS, and the well organized battery structure with lithium diffusion percolation path and the low solid contact resistance is obtained without any defects and undesirable reaction from sintering method.