Self-Healing Janus Interfaces for High-Performance LAGP-Based Lithium Metal Batteries

The application of NASICON-type Li 1.5 Al 0.5 Ge 1.5 P 3 O 12 (LAGP) solid electrolyte in lithium (Li) metal batteries has been retarded by its instability toward metallic Li and the poor interfacial compatibility with cathodes. Here we report a durable LAGP-based Li metal battery by employing self-healing polymer electrolytes (SHEs) as Janus interfaces. The SHEs were constructed on both sides of LAGP pellets by in situ polymerizing a functional monomer and a cross-linker in ionic liquid-based (anodic side in contact with Li metal) or adiponitrile (AN)-based (cathodic side) electrolytes. The as-developed SHEs show flame-retardant, high ionic conductivity (>10 –3 S cm –1 at 25 °C), excellent interfacial compatibility with electrodes, and effective inhibition of Li dendrite formation. The LAGP-based Li metal||LiMn 2 O 4 batteries with the SHE interfaces deliver a high reversible capacity with a long cycle.