The Europium-Based Artificial Solid Electrolyte Interphase for High-Performance Aqueous Zinc-Ion Batteries

With their high safety, high specific capacity, and low economic cost, the environmentally friendly aqueous zinc-ion batteries (AZIBs) are a prospective energy storage technology. However, the challenges faced, such as promiscuous growth of dendrites, water-related corrosion reactions, and weak ion migration ability, significantly affect the development of AZIBs. Herein, poly(vinylidene fluoride) (beta-PVDF) with high polarity was used as carrier, and a certain amount of europium chloride was doped to create an artificial solid electrolyte interface (ASEI) layer with hydrophilicity (denoted as PVDF-Eu). The resulting ASEI facilitates the uniform distribution of zinc ions (Zn2+), so as to enable uniform Zn deposition. Additionally, the ASEI can effectively suppress the side reactions and improve the cyclic stability of the cells. Consequently, with the effective assistance of the ASEI, the symmetrical Zn//Zn cell can achieve stable plating/stripping for 500 h at a current density of 20 mA cm-2. The Zn//Cu asymmetrical cell can achieve stable cycles of up to 2250 with an initial Coulombic efficiency of 98.5%. The capacity retention rate of a sodium vanadate based zinc-ion full cell reaches 90.6% after 900 cycles at 10 A g-1. This ASEI strategy demonstrates a method to enhance the performance of AZIBs.