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

Abstract

For lithium metal batteries (LMBs), the intrinsic issues of lithium dendrites and an unstable interface between the 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. Constructing a V₁₀ artificial solid electrolyte interface (ASEI) protective layer on lithium metal is a simplified and effective strategy for suppressing the growth of lithium dendrites. During the lithium plating/stripping process, V₁₀ reversibly transforms into Li_x[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 the anode surface. Therefore, the electric field strength on the lithium anode surface is adjusted to suppress dendrite growth. Additionally, V₁₀ accelerates the desolvation of lithium ions 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 mA h cm⁻², with an overpotential of only 110 mV. The assembled Li–S cells demonstrate excellent rate performance, achieving the reversible capacity of 470 mA h g⁻¹ under 5C.