Dynamic surface protective layer on a metallic lithium anode with electronic and ionic dual conductivity

A dynamic surface protective layer is formed by the electrochemical polymerization of polycyclic aromatic hydrocarbons. The newly formed Li dendrites can become dissolved in the protective layer, forming a conjugated Li+ and a dislocated e− π system. The protective layer is electronic and ionic dual conductive, which significantly reduces the interfacial impedance. Li dendrite formation can be mitigated since the newly formed Li dendrite becomes dissolved in the protective layer. The dissolved Li can disperse throughout the Li electrode surface and become re-deposited. Due to the elastic nature of the protective layer, it can stay on the Li surface during the Li volume change. The dissolution of Li dendrite and the formation of the elastic protective layer are visually observed in an in-situ electrochemical optical experiment.