Design of Novel Solid Electrolytes and Fabrication of High-Performance Solid Batteries

In recent years, a good number of fast ionic conductors have been studied as solid electrolytes for Li-ion or Na-ion batteries. Here we will present our understanding on the advantages and disadvantages of different types for solid electrolytes, including their electrochemical properties, synthesizability, and compatibility in solid cells. Specifically, we will share our recent progresses on rational design of novel sulfide and halide solid electrolytes based on in-depth characterization and understanding of their crystal structure and structure-property relationship. Sulfides commonly offer high room temperature conductivity and good anode compatibility, but their syntheses are tricky and relatively expensive. Halides commonly show lower room temperature conductivity than sulfides, but they are easy to synthesize and stable against air. We will report the crystal structure characterization of sulfide and halide solid electrolytes with using ex situ and in situ high resolution synchrotron X-ray and neutron diffraction and pair distribution function analysis, coupled with variable temperature electrochemical impedance spectroscopy. The design of long-lasting, high-performance solid cell with using the novel electrolytes will also be discussed, including materials selection, cell fabrication and electrochemical testing conditions and protocols.