Microwave synthesis and sintering of Bi₄Ti₃O₁₂, the Aurivillius compound: structural and chemical effects of attempted lithiation

Abstract

Layered bismuth titanate, Bi₄Ti₃O₁₂ (BTO) (Aurivillus phase) has been synthesized using microwave route. BTO has been prepared using conventional ceramic method also for comparison. Li⁺ intercalation into BTO has been attempted using a soft chemistry route. Inductively coupled plasma (ICP) has been used to estimate Li⁺ quantitatively and the lithiated sample is found to be Li_2.38Bi₄Ti₃O₁₂. Infrared and UV-visible spectroscopies along with ESR and ⁷Li MAS NMR have been used to characterize the lithiated compound. Electrical conductivity of lithiated sample has also been examined. The pristine BTO has been sintered both using microwave and conventional heating. Sintered samples reveal very interesting morphology. The characteristic plate like growth in sintered samples appears more prominently in microwave sintering. Schematic molecular orbital (MO) diagram based band structure has been proposed which provides consistent rationalization of the observed properties.