Understanding Lithium Hydride in Lithium Metal Batteries: Advances, Controversies, and Perspectives

Lithium metal batteries exhibit significantly higher energy densities compared to state-of-the-art lithium-ion batteries. However, their commercialization is critically impeded by safety hazards arising from lithium dendrite growth. In 2018, a new dendrite of lithium hydride (LiH) was identified within the lithium metal anode, garnering widespread attention and inciting intense debate. Research on the location, morphology, content, formation mechanisms, and effects of LiH on battery performance has yielded diverse and sometimes conflicting results. This review summarizes the latest advancements in LiH research, discusses the prevailing controversies, and outlines future perspectives in the field.