Developing Low-Temperature All-Solid-State Batteries for Aerospace Applications

Though conventional lithium-ion batteries (LIBs) are well-suited for moderate climates in most areas, the high latitude and high altitude climates on Earth and the wide operating temperature range in space environments pose a challenge to conventional LIBs that utilize organic liquid electrolytes prone to increased viscosities and freezing at ultracold temperatures. In comparison, all-solid-state batteries (ASSBs) with solid-state electrolytes (SSEs) do not freeze and provide expanded temperature tolerance. Additional key benefits, including enhanced safety and tunable cell performance, make ASSBs promising for extreme terrestrial and space applications. However, while ASSBs have demonstrated promising electrochemical performance at elevated temperatures, the operation suffers significantly at lower (such as subzero) temperatures due to sluggish charge transfer kinetics and lithium-ion transport. This diminished performance is further exacerbated by the poor interfacial contact inherent to solid-state systems. To enable ASSBs for wide temperature range in aerospace applications, it is critical to find battery materials with adequate ionic conductivity and electrochemical stability, especially at low temperatures, while also developing methods to improve solid-solid interfacial contacts and ion transport across various interfaces. In this exploratory work, we aim to identify SSEs compatible with low temperature operation. A group of commercial and in-house-synthesized SSEs are screened for ionic conductivity and activation energy using electrochemical impedance spectroscopy. The dual effects of applied stack pressure and temperature on SSE performance are evaluated using various battery cell configurations. The results of this study will be presented and discussed.