Li-ion batteries have been successf

Li-ion batteries have been successfully commercialized due to their long cycle life and high charge/discharge rate, but their energy densities with conventional graphitic anodes are insufficient for emerging applications, such as electric vehicles, grid-level energy storage , and personal electronic devices. As such, Li metal anodes that have the lowest known electrochemical potential (−3.04 V vs the standard hydrogen electrode), low density (0.53 g cm−3), and a theoretical capacity of 3860 mAh g−1are poised to meet the needs of next-generation energy storage.[2–4] Nevertheless, current Li metal batteries that use combinations of organic liquid and salt as electrolytes suffer from rapid capacity fade upon cycling.[5–7] Li metal anodes lead to inhomogeneous and unstable solid electrolyte interphases (SEIs), promote dendrite growth that short the cell, consume electrolyte during cycling, and create potential problems with flammability and explosions.