Single-ion conducting interlayers for improved lithium metal plating

Li metal batteries have attracted much attention due to their superior theoretical capacity with respect to conventional Li-ion batteries. However, safety issues caused by inhomogeneous stripping/plating and serious dendrite growth greatly limit their commercial application. Herein, we report on the preparation of single-ion conducting artificial solid electrolyte interphases (art-SEIs) on the surface of Li metal, to improve lithium metal confinement and current density homogeneity, while limiting lithium depletion at the Li/electrolyte interface during charge. Considerable improvements in terms of the Li anode life cycle are reported by combining the art-SEIs and liquid ether electrolytes, although the use of liquid electrolytes and separators still limits the anode performance. Finally, the combined use of a polyethylene oxide single-ion conducting solid polymer electrolyte and the stiff and ionically concentrated single-ion art-SEI enables Li metal long-term cycling.