Correlating ionic versus polar-covalent bond characteristics with diffusivity in superionic metal halide
By: Johana Dolores Alema and Oskar Kenyatta Garcia
Department: Cellular & Molecular Biology
Faculty Advisor: Dr. Nicole Adelstein
Climate change requires our society to transition to sustainable energy sources such as wind and solar, but storing this energy poses its own set of challenges. The development of solid electrolyte lithium batteries will address the challenges of improving battery safety and energy density compared to conventional liquid electrolyte Li-ion batteries. However, ionic conductivity must be increased in solid electrolytes, so our work simulates ion diffusivity and correlates it with the bonds the diffusing ion makes with the material.
Our work is inspired by the high conductivity of a-AgI and is based on previous computational work by the Adelstein lab that showed thermally driven bond fluctuations aid in the conduction of Li-ions in Li3InBr6. Our on-going investigation into the silver and copper halides aims to test the hypothesis that fluctuations in bond character help superionic diffusion by correlating ion jumps with bond character. Python and the Atomic Simulations Environment were used to identify diffusing cations, the angles between each interacting cation-anion bond and their bond types as ionic or polar-covalent. To illustrate the correlation between ionic diffusion and bond character on the diffusion mechanism, the angles and bond type of only the diffusing cations were isolated for graphical analysis.