Submicron interlayer for stabilizing thin Li metal powder electrode

Abstract

The surface area of the lithium metal electrode must be considered when attempting to suppress dendritic growth of lithium metal, as surface area can lower the effective current density. For this reason, lithium metal powder (LiMP) has attracted much attention for use in electrodes because of its higher surface area. However, repeated cycling, even in aging time, leads to delamination of lithium particles from flat metal current collectors and results excess dead lithium particles, even in LiMP electrodes. Herein, this problem is addressed by coating submicron-thickness carbon interlayers on copper current collectors for LiMP electrodes. This thin carbon layer plays important roles in both maintaining the interfacial contact between Cu foil and LiMP particles and lowering overpotential in Li/Li symmetric cells, which leads to improve electrochemical performance in thin LiMP (40 μm) based cell. These enhancements are related to the enlarged surface area, as confirmed by higher adhesion of the electrode after precycling. Furthermore, the carbon materials are also believed to contribute to seeding for efficient lithium nucleation. Thus, thin carbon layers on current collectors can provide simple but powerful enhancements to the electrochemical performance of high-energy-density LMSBs. © 2020 Elsevier B.V.