Solid-State Synthesis of 70 nm Li^sub 4^Ti^sub 5^O^sub 12^ Particles by Mechanically Activating Intermediates with Amino Acids

A novel synthetic method of fine particles of highly pure ... with the smallest possible particle size was proposed. A stoichiometric mixture of ...*... and anatase fine particles of ca. 50 nm was calcined at 773 K to obtain an intermediate, comprising ... and unreacted titania. The intermediate was then intensively milled by a planetary ball mill for 1 h. After adding an amino acid, glycine, alanine (ALA), or l-phenylalanine (PHE), the mixture was further milled under a milder condition for another 3 h and subjected to a second calcination at 973 K for 1 h to obtain ... with a phase purity above 97%. When we used ALA or PHE as an additive, the microscopically determined average particle size of ... was 70±10 nm. The mechanisms and significance of the present two-step calcination with mechanical activation and addition of an amino acid to the intermediate were discussed in terms of the topotactic nature of transformation between the two layer-structured species: ... and ... (ProQuest: ... denotes formulae/symbols omitted.)