Towards lower annealing temperatures and enhanced functional properties in aerosol-deposited piezoelectric thick films: A study of the effect of Li additive on BaTiO3 films

The effect of incorporating Li additive (Li₂CO₃) into aerosol deposited BaTiO₃ thick films was investigated. The addition of Li₂CO₃ to the deposited powder facilitated grain growth during post deposition process, even for low annealing temperatures (≤ 700 °C). Therefore, this additive decreased the threshold for ferro/piezoelectricity recovery from 800 °C to 650 °C. Furthermore, annealing at temperatures ≥ 800 °C yielded grain sizes ranging from 100 nm to 700 nm, unprecedented in our previous investigations. Substantially improved ferroelectric and piezoelectric responses were obtained in the 800–900 °C range, with P_r values doubling to 12 µA.cm⁻² for films annealed at 900 °C. Moreover, the use of this additive improved leakage behavior, achieving a leakage current density of 0.1 µA.cm⁻² and an electrical resistivity of 10¹¹ Ω.cm at 700 °C. Microscopic analyses revealed a carbon containing secondary phase at grain boundaries, probably corresponding to Li₂CO₃.