Surface-Based Li+ Complex Enables Uniform Lithium Deposition for Stable Lithium Metal Anodes

Uncontrollable Li dendrites growth and low Coulombic efficiency (CE) have severely prevented the practical applications of Li metal anode. Here, we propose to use poly(ethylene glycol) (PEG) as an electrolyte additive for suppressing dendritic growth and improving the cycling stability of Li metal anode. The PEG molecule can be absorbed on the surface of Li metal and complex with the Li+ ions effectively, which ensures a homogeneous diffusion of Li+ near the electrode surface and fundamentally avoids dendrite formation. Thus, full cells with LiFePO4|Li configuration can even maintain ∼100% capacity with CE > 99.5% after 250 cycles at 5.0 C.