High‐Throughput Experimentation Unveils Composition – Structure – Conductivity Relationships in the Extended LiPON System

A high‐throughput experimental approach is developed to assess the correlations between chemical composition, structure and conduction properties of inorganic solid ionic conductors. This approach covers the preparation of a large number of samples by combinatorial synthesis, followed by fast characterization of the material library. The approach is primarily based on combinatorial synthesis by magnetron co‐sputtering and the characterization of thin film samples where lithium phosphorus oxynitride (LiPON) is chosen as a case study. A library of 76 LiPON materials is prepared in one experiment from the reactive co‐sputtering of LiPO3 and Li3PO4 in a N2 atmosphere. A specific sample design allows conducting thickness and impedance measurements, Raman spectroscopy, then fast and spatially‐resolved chemical analysis by Laser‐Induced Breakdown Spectroscopy (LIBS) on each material. Particular developments are devoted to this technique to achieve quantitative analysis of lithium in thin films. The materials cover a wide range of compositions with 0.95<Li/P<2.03 and a high N/P nitrogen content of ≈1.0‐1.2. Two distinct compositional ranges can be distinguished. For 0.95<Li/P<1.2, conductivity increases and the PO3− chains gradually disappear, whereas for 1.2<Li/P<2.03, conductivity stabilizes despite continuous structural evolution, in parallel with an increase in charge carrier concentration.