High-throughput exploration of the Na₂O-ZrO₂-SiO₂-P₂O₅ composition space using thin film material libraries

The composition space Na₂O-ZrO₂-SiO₂-P₂O₅ was explored using thin film material libraries and high-throughput characterization methods. The combinatorial synthesis comprised non-reactive magnetron co-sputtering at room temperature from two elemental targets Zr and Si, and a compound Na₃PO₄ target followed by a two-step annealing process. The NASICON phase formed for all compositions on the material library produced at the optimized deposition parameters, also displaying a phase-pure Na_1+xZr₂Si_xP_3−xO₁₂ (x = 0.4—2.9) region. Analytical TEM analysis of the NASICON phase at a measurement area with stoichiometric composition revealed a fine-grained microstructure and homogeneous Si distribution, in contrast to Na-P excess conditions, where large Si-free NASICON grains have formed.