Properties of Lithium Metal for Solid State Batteries

Abstract

The advancements in lithium ion batteries (LIBs) over the last three decades has significantly altered the modern world. The availability of efficient, portable electrical energy storage has enabled the proliferation of personal electronics, improved the viability of renewable energy sources such as wind and solar, and begun to transform the transportation sector.

Current LIB technology has enabled a diverse electric vehicle (EV) market in passenger cars, however adoption remains low compared to internal combustion engine (ICE) vehicles. Modern EVs still require customers to compromise when compared to ICE powered vehicles, primarily in the areas of cost and/or range. These limitations come from the performance of available technology, which continues to drive the evolutionary improvement of LIBs. The ecosystem of energy storage would benefit greatly from a revolutionary increase in battery performance. As the third lightest element and the lowest reduction potential, lithium metal is the ideal battery anode and has been a focal point since the 1960s. Despite decades of research, many technical challenges have prevented the usage of lithium anodes. Recent discoveries of several solid state electrolytes has renewed the prospects of lithium anode adoption.

In this work, we will study several of the properties of lithium metal in the context of future lithium metal solid state batteries (LMSSB). Despite the long history of lithium metal in batteries, relatively little is known regarding its elemental mechanical properties and their sensitivities to parameters like aspect ratio, temperature or strain rate. This is particularly true in the thin film form factor required by LMSSBs. Lithium metal is not stable in the ambient environment, which has complicated mechanical studies in addition to raising questions regarding its safety. Due to these knowledge gaps, this work will also explore the potential safety implications of LMSSB arising from the usage of lithium metal. Our study will inform future designers of LMSSB of the mechanical limits of lithium metal and assess the potential safety consequence of its possible future use.