What dictates soft clay-like lithium superionic conductor formation from rigid salts mixture

Soft clay-like Li-superionic conductors, integral to realizing all-solid-state batteries, have been recently synthesized by mixing rigid-salts. Here, through computational and experimental analysis, we clarify how a soft clay-like material can be created from a mixture of rigid-salts. Using molecular dynamics simulations with a deep learning-based interatomic potential energy model, we uncover the microscopic features responsible for soft clay-formation from ionic solid mixtures. We find that salt mixtures capable of forming molecular solid units on anion exchange, along with the slow kinetics of such reactions, are key to soft-clay formation. Molecular solid units serve as sites for shear transformation zones, and their inherent softness enables plasticity at low stress. Extended X-ray absorption fine structure spectroscopy confirms the formation of molecular solid units. A general strategy for creating soft clay-like materials from ionic solid mixtures is formulated. Soft clay-like superionic conductors are integral for realising all-solid-state batteries. Here the authors provide fundamental insights into how a soft clay-like Li-superionic conductor, and soft clays in general can be created from a rigid-salts mixture.

Automated summary

In this study, the authors investigate the formation mechanism of soft clay-like Li-superionic conductors. By mixing rigid salts and promoting the formation of molecular solid units during anion exchange, they are able to create a material with softness and plasticity. This research provides fundamental insights and a general strategy for creating soft clay-like materials from a mixture of rigid salts.