Nanoscale Mapping of Extrinsic Interfaces in Hybrid Solid Electrolytes

Inorganic-organic hybrid solid electrolytes are promising material systems for all solid-state batteries (ASSBs). These electrolytes contain numerous solid-solid interfaces that govern transport pathways, electrode vertical bar electrolyte compatibility, and durability. This paper evaluates the role that electrode vertical bar electrolyte interfaces and electrolyte structure have on electrochemical performance. Atomic force microscopy techniques reveal how mechanical, adhesion, and morphological properties transform in a series of model hybrid solid electrolytes. These measurements are mapped to sub-surface microstructurel features using synchrotron nano-tomography. Hybrid solid electrolytes with shorter polymer chains demonstrate a higher adhesion (>100 nN), Young's Modulus (6.4 GPa), capacity (114.6 mAh/g), and capacity retention (92.9%) than hybrid electrolytes with longer polymer chains (i.e., higher molecular weight). Extrinsic interfacial properties largely dictate electrochemical performance in ASSBs. Microstructurel control over inorganic constituents may provide a means for tailoring interfacial properties in hybrid solid electrolytes.