A High-Throughput Platform for Combinatorial Synthesis and Characterization of Thiophosphate Solid Thin-Film Electrolytes

Research in thin-film battery materials is scarce, and reports of sulfur-based solid electrolytes and battery electrodes in thin-film form are particularly few. Even if we disregard the possible practical applications of thin-film materials in bulk solid-state batteries, dedicated work on sulfide battery materials in thin-film form would be highly beneficial for a very simple reason. Bulk synthesis of sulfide solid electrolytes is not amenable to parallelized, high-throughput experimentation by combinatorial methods. Conversely, an appropriately designed thin-film deposition system is an ideal platform for rapid exploration of new battery materials.<br/><br/>In this contribution, I will present our recently acquired, highly customized thin-film synthesis platform dedicated to air-sensitive sulfides, thiophosphates and related materials containing sulfur and phosphorus. To the best of my knowledge, this is the only synthesis platform in the world where it is possible to deposit thin-film thiophosphate superionic conductors of any elemental composition in a high-throughput, combinatorial fashion. Our thin-film deposition setup is designed to easily obtain compositional gradients (e.g., a P/S ratio gradient in one direction and a Li/Ge ratio in the perpendicular direction). Together with the automated, mapping-type characterization instruments in our laboratories, these combinatorial methods enable fast screening of multicomponent phase diagrams of sulfides (as well as process parameters at constant composition) in the search for optimal properties in emerging or completely new battery materials. Materials of interest can be either electrodes or solid electrolytes.<br/><br/>As a material scientist within the optoelectronics field specializing in sulfides, I hope that this contribution will promote discussion and potential future collaboration with sulfide battery experts.