The Mechanical Behavior of Li Metal Anodes During Electrochemical Cycling

Pure lithium metal anodes are highly promising due to their superior capacities yet remain challenging to implement commercially. Key remaining challenges include non-uniform deposition of the Li metal which can lead to dendrite formation and capacity loss, as well as mechanical stresses and strains induced by the “infinite volume change” associated with its host-less nature during electrodeposition. These issues are intimately connected to the mechanical properties of lithium itself, as well as details of its behavior during electrochemical cycling. With these issues in mind, we investigated the mechanical response of pure Li metal during electrodeposition at room temperature. The tests revealed rate-dependent mechanical behavior during electrodeposition, which we largely attribute to the strain-rate dependent mechanical properties of lithium itself by drawing an analogy between the deposition rate and the strain-rate. This talk will further discuss the practical implications of these experimental observations, particularly concerning dendrite growth in batteries. Specifically, this talk will provide general insight into lithium penetration into solid-state electrolytes, which must be prevented to fully harness the potential of lithium metal anodes in future battery technologies.