Processing–Structure–Function Relationships in Solid–State Batteries

Abstract

Transportation contributes to almost one-quarter of the current energy related greenhouse gas emissions in the United States. Electrification of the transportation sector is key to meet the emissions criteria set by the Paris climate agreement in 2016 (< 2 °C pathway). Electrification of the transportation sector relies on radical re-imagining of energy storage technologies to provide affordable, high energy density, durable and safe systems. Next generation energy storage systems will need to utilize high energy density anodes, like Li or Na metal to achieve the required performance metrics (longer vehicle range, long life, production costs, safety). Solid-state batteries (SSBs) comprising of solid electrolytes (SEs) are promising alternatives for achieving these metrics by enabling energy dense alkali metal anodes and high voltage cathodes. However, solid state batteries suffer from poor capacity retention, coulombic efficiencies as well as lifetimes which impede their practical applications. An understanding about structure-function relationships in solid state batteries can enable high performing systems that are commercially viable. This research seeks to use direct and indirect characterization techniques to unravel dynamic material transformations in solid state batteries. Correlating the microstructure of solid electrolytes with their performance is achieved through synchrotron imaging techniques combined with electrochemical characterization and modeling. Furthermore, operando studies are carried out to evaluate evolution of structure in all-solid-state batteries as a function of their performance. Synchrotron tomography and diffraction studies provide valuable insight into the impact of electrolyte microstructure (grains, pores), electrode morphology and interphase chemistry on the electrochemical performance of solid-state batteries. Finally, the information derived from the previous studies is leveraged to engineer high performance electrolyte systems. The overarching goal of the proposed research is aimed at understanding the fundamental processing-structure-function correlations in solid-state electrolytes. The results of these studies are expected to inform rational design of next generation of solid-state battery systems. Further, the proposed research will contribute towards enabling scalable production of high-performance solid electrolytes and towards commercialization of these systems.