Highly Reversible Zinc Metal Anodes Enabled by Solvation Structure and Interface Chemistry Modulation

摘要

Aqueous Zn?ion batteries (AZIBs) promise appealing advantages including safety, affordability, and high volumetric energy density. However, rampant parasitic reactions and dendrite growth result in inadequate Zn reversibility. Here, a biocompatible additive, L-asparagine (Asp), in a low-cost aqueous electrolyte, is introduced to address these concerns. Combining substantive verification tests and theoretical calculations, it is demonstrated that an Asp-containing ZnSO_4 electrolyte can create a robust nanostructured solid-electrolyte interface (SEI) by simultaneously modulating the Zn~(2+) solvation structure and optimizing the metal-molecule interface, which enables dense Zn deposition. The optimized electrolyte supports excellent Zn reversibility by achieving dendrite-free Zn plating/stripping over 240 h at a high Zn utilization of 85.5 in the symmetrical cell and an average 99.6 Coulombic efficiency for over 1600 cycles in the asymmetrical cell. Adequate full-cell performance is demonstrated with a poly(3,4-ethylenedioxythiophene) intercalated vanadium oxide (PEDOT-V_2O_5) cathode, which delivers a high areal capacity of 4.62 mAh cm~(?2) and holds 84.4 capacity retention over 200 cycles under practical conditions with an ultrathin Zn anode (20 μm) and a low negative/positive capacity ratio (≈2.4). This electrolyte engineering strategy provides new insights into regulating the anode/electrolyte interfacial chemistries toward high-performance AZIBs.