High-entropy mechanism to boost ionic conductivity

Advances in solid-state batteries have primarily been driven by the discovery of superionic conducting structural frameworks that function as solid electrolytes. We demonstrate the ability of high-entropy metal cation mixes to improve ionic conductivity in a compound, which leads to less reliance on specific chemistries and enhanced synthesizability. The local distortions introduced into high-entropy materials give rise to an overlapping distribution of site energies for the alkali ions so that they can percolate with low activation energy. Experiments verify that high entropy leads to orders-of-magnitude higher ionic conductivities in lithium (Li)-sodium (Na) superionic conductor (Li-NASICON), sodium NASICON (Na-NASICON), and Li-garnet structures, even at fixed alkali content. We provide insight into selecting the optimal distortion and designing high-entropy superionic conductors across the vast compositional space.

Automated summary

Experiments demonstrate that using high-entropy metal cation mixes can improve the ionic conductivity of a compound, reduce reliance on specific chemistries, and enhance synthesizability. Local distortions introduced into high-entropy materials create an overlapping distribution of site energies for alkali ions, allowing them to percolate with low activation energy. This study provides important insights into selecting optimal distortion and designing high-entropy superionic conductors across a wide compositional space.