Chlorine-rich lithium argyrodite enables stable interfacial Li plating/stripping behavior in anode-free all-solid-state batteries

Abstract

Reversible Li plating/stripping of anode-free all-solid-state batteries is enabled by the synergistic effect of superionic Li _5.5PS _4.5Cl _1.5 and Li-alloying interlayer.

Abstract

Anode-free all-solid-state batteries (AFASSBs) have the advantages of a simplified manufacturing process because of the absence of a lithium anode. Here, we systematically investigate the effect of various solid electrolytes (SEs) on the electrochemical properties of AFASSBs without stack pressure. The results show that argyrodites promote Li plating/stripping, whereas other SEs are rapidly degraded. Interestingly, Li _5.5PS _4.5Cl _1.5, with an ionic conductivity of 9.8 mS cm ⁻¹, provides better capacity and cyclability than Li ₆PS ₅Cl (4.3 mS cm ⁻¹), indicating that superionic halogen-rich Li-argyrodites are beneficial for AFASSBs. A model study based on a prelithiated current collector reveals that the elimination of the initial Li nucleation reaction further improves the interfacial stability of Li _5.5PS _4.5Cl _1.5. Consequently, the combination of Li _5.5PS _4.5Cl _1.5 and Ag–C achieves the highest coulombic efficiency owing to the synergistic effect of a chlorine-rich SE and an Li-alloying interlayer. These findings show the potential of utilizing superionic halogen-rich Li-argyrodites and alleviating the Li nucleation overpotential in AFASSBs.