  In the pursuit of advanced energy storage solutions, the crystal structure of
ionic conductors plays a pivotal role in facilitating ion transport. The
conventional structural design principle that compounds with the body-centered
cubic (BCC) anionic frameworks have high ionic conductivity is well known. We
have extended the conventional design principle by uncovering that many of the
anionic frameworks of Ag-ion conductors are characterized by tetrahedrally
packed (TP) structures. Leveraging our findings, we have virtually screened TP
framework compounds, uncovering their intrinsic potential for superior ionic
conductivity through first-principles molecular dynamics simulations. Our
design principle is applicable to Ag$^+$ and other mobile ions, including
Li$^+$ and F$^-$. We proposed the Met2Ion method to generate ionic crystal
structures using metal crystal structures as templates and demonstrated that
new ionic conductors with TP frameworks can be discovered. This work paves the
way for the discovery and development of next-generation energy storage
materials with enhanced performance.
