Coulombic Efficiency of Lithium Deposition and Stripping on Lithium Metal: A New Method for Measuring

Abstract

Rechargeable lithium metal batteries (RLMBs) have been extensively investigated as a next-generation battery for electric vehicles because of their two times higher specific energy density than conventional lithium-ion batteries. However, RLMBs have not been commercialized yet, because of the low coulombic efficiency (CE) of the lithium deposition and stripping process and lithium dendrite formation. CEs measured by a conventional method with a Li/electrolyte/Cu were considerably lower than those measured using full cells of Li/electrolyte/oxide cathode. The discrepancy is considered to be due to the non-reversibility of the Cu electrode for the lithium deposition and stripping process. Here, we propose a new method to determine the CE of lithium deposition and stripping on lithium metal from the loss of electrolyte using a Li/electrolyte/Li cell with a limited amount of electrolyte.