Exploring Chemical Space and Substitution Effects to Develop Stable, High-Conductivity Solid-State Electrolytes for Na-Ion Batteries

Chi-Hsuan Lee^1*, Chun-Wei Pao¹

¹Research Center for Applied Sciences, Academia Sinica, Taipei city, Taiwan

* Presenter:Chi-Hsuan Lee, email:frankreichparis@gmail.com

All-solid-state batteries (ASSBs) are well-positioned to cater to the increasing demand for high-energy-density storage technologies. Developing such a battery system requires solid-state electrolytes (SSEs) with high ion conductivity at room temperature, along with excellent electrochemical stability and interface compatibility. Sodium-ion batteries (SIBs) are considered a promising alternative to lithium-ion batteries (LIBs) for large-scale energy storage systems because sodium is highly abundant, environmentally friendly, and inexpensive. First-principle calculations reveal the significant impact of varying compositional ratios of halides on the structural properties and stabilities. The evaluation of Na-ion conductivities is conducted using ab initio molecular dynamics simulations, which are enhanced by active machine learning algorithms in advance. The calculated mixing energy among halogen substitutions serves as an indicator of phase stability, while aliovalent cation substitutions induce structural distortions, thereby adjusting Na-ion activation energy and enhancing conductivity.

Keywords: ab-initio molecular dynamics, ionic conductivity, activation energy