Selection of Redox Mediators for Reactivating Dead Li in Lithium Metal Batteries

摘要

Li metal batteries have suffered from dendrite growth and its derived deadLi formation for a long time. A new lithium restoration method through theshuttling of redox mediators has been proposed recently. However, the sidereaction of severe self-discharge often occurs when some redox mediators areused. Here, a selection principle of redox mediators for reactivating dead Liin lithium metal batteries is put forward, which is able to reactivate the deadLi effectively and reduce the self-discharge at the same time. Three redoxmediators of ferrocene (Fc), 10-methylphenothiazine (MPT), and thianthrene(Th) with different redox potentials are tested in LiFePO_4Cu anode-free Limetal batteries to clarify the selection principle. Furthermore, 2,2,6,6-tetramethylpiperidinooxy(TEMPO), which is speculated to be a suitable one forreactivating dead Li in lithium metal batteries, is verified. This work providesa universal selection principle of redox mediators and may boost its practicalapplication in Li metal batteries.