Exploration of Metal Alloys as Zero-Resistance Interfacial Modification Layers for Garnet-Type Solid Electrolytes

摘要

A solid-state battery with a lithium-metal anode and a garnet-type solidelectrolyte has been widely regarded as one of the most promising solutionsto boost the safety and energy density of current lithium-ion batteries.However, lithiophobic property of garnet-type solid electrolytes hinders theestablishment of a good physical contact with lithium metal, bringing abouta large lithium/garnet interfacial resistance that has remained as the greatestissue facing their practical application in solid-state batteries. Herein, a meltquenchingapproach is developed by which varieties of interfacial modificationlayers based on metal alloys can be coated uniformly on the surface ofthe garnet. It is demonstrated that with an ultrathin, lithiophilic AgSn_(0.6)Bi_(0.4)O_xcoating the interfacial resistance can be eliminated, and a dendrite-freelithium plating and stripping on the lithium/garnet interface can be achievedat a high current density of 20 mA cm~(?2). The results reveal that the uniformcoating on the garnet surface and the facile lithium diffusion through thecoating layer are two major reasons for the excellent electrochemical performances.The all-solid-state full cell consisting of the surface modified garnettypesolid electrolyte with a LiNi_(0.8)Mn_(0.1)Co_(0.1)O_2 cathode and a lithium–metalanode maintains 86 of its initial capacity after 1000 stable cycles at 1 C.