Solid-State NMR Guided Discoveries of Low-Cost, High-Performance Solid Electrolytes

Developing low-cost and high-performance solid electrolytes is key to producing inexpensive solid-state batteries. Leveraging cost-effective precursors for synthesizing highly conductive and stable solid electrolytes under mild conditions is a promising approach. We have demonstrated the feasibility of such an approach in several cases, including thiophosphate-, phosphate-, and halide-based solid electrolytes. Solid-state NMR investigations of structure-ion transport correlation have been critical to guiding the synthesis and optimization of these solid electrolytes. In particular, we have employed high-resolution NMR spectroscopy complemented by diffraction techniques to determine long- and short-range structures, NMR relaxometry to probe ion dynamics, NMR diffusometry to measure tracer diffusivity, and electrochemically driven tracer-exchange NMR to map out ion transport pathways. Such a systematic investigation allows for a fundamental understanding of how structural attributes affect different aspects of ion transport properties. In conduction with <i>in situ</i> NMR, we can establish synthesis-structure-property relationships, which we use to advise synthesis strategies.