Lithium metal due to its high theoretical gravimetric and volumetric capacity (3862 Ah/kg and 2085 Ah/L) is considered to be one of the most promising candidates as negative electrode material in next generation batteries (such as S||Li and O2||Li) and also enabling all-solid-state lithium metal batteries (ASSMB) with conventional cathodes (e.g. NMC 622||Li). Besides conventional lithium foil electrodes, several studies reported that lithium powder can be successfully utilized in rechargeable lithium metal batteries (LMBs) with liquid or solid-state electrolytes. However, lithium powder electrodes (LPE) prepared by slurry casting method suffer from low capacity utilization during the lithium electrodissolution process.
Herein, we further shed light on the degradation mechanisms of LPE, during OCV periods when there is no current flowing in the cell. When aged with a common non-aqueous liquid electrolyte (1M LiPF6 in EC:DEC 3:7 w/w), LPE demonstrate obvious signs of lithium dissolution and, as a result, lower capacity utilization compared to calculated values. We have designated such a behavior as corrosion of lithium that, as will be shown, is dependent of another cell components with which lithium powder comes in contact. In addition, corrosion-current and -rate of LPE were determined, thus, providing us valuable parameters for monitoring of corrosion processes. In a broader context, these findings can be important not only for LPE, but also for conventional lithium metal electrodes.