Preparation and characterization of three dimensionally ordered macroporous Li5La3Ta2O12 by colloidal crystal templating for all-solid-state lithium-ion batteries

Three dimensionally ordered macroporous (3DOM) membranes of Li5La3Ta2O12 (LLTO) for all-solid-state lithium-ion batteries were prepared by using colloidal crystal templating of mono dispersed polystyrene (PS) spheres combined with sol–gel synthesis of LLTO precursor. During the sol–gel synthesis, the appropriate mixtures of CH3COOLi, La(NO3)3·6H2O and Ta(OC2H5)5 were dissolved in two different solvents to prepare garnet-type LLTO. Various sizes of mono dispersed (1, 3 and 5 μm) PS beads were used as a template to investigate the size effect of template on the network formation of LLTO membranes. The transformation from precursor solutions, which are added onto the PS template, to crystalline phase, was investigated by TG analysis and X-ray powder diffraction (XRPD). The morphology of the PS templates and the 3DOM garnet membranes were investigated by Scanning Electron Microscopy. The templates made from 5 μm PS spheres were found to be the most suitable template to obtain 3DOM membranes of LLTO.