High-Rate Lithium Metal Plating and Stripping on Solid Electrolytes Using a Porous Current Collector with a High Aperture Ratio

Abstract

Dendritic Li metal growth and low Coulombic efficiency hinder the Li metal negative electrode’s applications. Solid electrolytes (SEs) have the potential to inhibit the growth of dendritic Li metal due to their high mechanical strength and number of transmissions; however, the extrusion of the Li metal into voids and cracks in the SEs due to the increased mechanical stress of the Li metal during the plating reaction makes it difficult to prevent internal short circuits. Here, this obstacle was uniquely solved using a porous current collector (PCC) with a high aperture ratio. Li metal plating in many pores of the PCC prevented the increase of mechanical stress of the Li metal. Moreover, the combination with the SE, which also has a high tolerance to the dendritic Li metal growth, showed a synergic effect. Additionally, the Au coating on the PCC’s surface extended the Li plating/stripping performance. As a result, a record-high value of critical current density (the maximum plating/stripping current density without internal short circuits) over 6 mA cm–2 was recognized by the galvanostatic Li metal plating/stripping tests. Notably, the excellent cycle performance with a high average Coulombic efficiency of 98.7% for 300 cycles was also achieved in the Li electrode-free system. Our works exhibit the potential for attaining Li metal all-solid-state cells.