Utilizing decavanadate as an artificial solid electrolyte interface to effectively suppress dendrite formation on lithium metal anode

Abstract

For lithium metal batteries (LMBs), the intrinsic issues of lithium dendrites and unstable interface between lithium metal anode and electrolyte pose severe safety risks. In this study, a novel strategy is proposed for modifying the lithium surface using the decavanadate Na6V10O28⋅18H2O (V10) as a protective layer. The constructing V10 artificial solid electrolyte interface (ASEI) protective layer on lithium metal is a simplified and effective strategy for conquering lithium dendrites. During lithium plating/stripping process, V10 reversibly transforms into Lix[V10O28] (x = 6-9), serving as an “ion sponge” to absorb a large amount of lithium ions to compensate for the shortage of lithium ions on anode surface. Therefore, the electric field strength on lithium anode surface is adjusted to suppress dendrites growth. Additionally, V10 accelerates the desolvation of lithium ion from solvent clusters, which contributes to the homogeneous migration of lithium ions. Consequently, Li//Li symmetric cells using V10 modified foils exhibit stable cycling for 1200 h under the conditions of a current density of 5 mA cm-2 and an areal capacity of 1 mAh cm-2, with an overpotential of only 110 mV. The assembled Li-S cells demonstrate excellent rate performance, achieving the reversible capacity of 470 mAh g-1 under 5 C.