An insulating material in a structured host enables sustainable formation of a granular Li metal for highly durable Li metal battery

Abstract

© 2022 Elsevier B.V.For using Li metal anode, controlling Li metal morphology for long-term cycles is an essential requirement, but the porous Li metal easily form due to a dendritic Li growth. Here, we report on a novel strategy to reversibly form a granular Li metal by confining Li deposition sites and controlling the Li metal morphology via a structured functional host that is composed of small portion of a Li-alloying region and large portion of an insulating region. The insulating region confines the nucleation sites to the Li-alloying region because the nucleation cannot occur in the insulating region, and strongly affects the growth/morphology of the Li metal because the insulating particles mitigate the Li+ concentration around the Li-alloying particles. The persistent effects of the confinement and control of the Li metal morphology enable to sustainably form the granular Li metal. The Cu electrode with the functional host structure achieve Coulombic efficiency of >98% over 500 cycles, and can reversibly deposit Li metal with LiCoO2 cathode even in typical standard carbonate electrolytes. The findings reveal novel capabilities of insulating materials for sustainable use of Li and provide a new avenue for designing practical use of Li metal for durable Li metal batteries.