Zinc anode stabilized by an organic-inorganic hybrid solid electrolyte interphase

Metallic zinc (Zn) anode holds great promise for aqueous batteries but suffers from the dendrite growth and water-induced side reactions due to the absence of a stable solid electrolyte interphase (SEI) layer. Herein, we propose an efficient strategy to in-situ build a robust organic-inorganic hybrid SEI on Zn electrode (denoted as SEI-Zn) by electrochemically pre-cycling Zn electrodes in an organic electrolyte consisting of zinc trifluoromethanesulfonate salt and triethyl phosphate solvent. The as-formed SEI features an organic-rich outer layer and an inorganic Zn3(PO4)2-ZnF2-ZnS rich inner layer arising from the reductive decomposition of the organic electrolyte, which can isolate active Zn from the bulk electrolyte and allow a rapid and uniform Zn2+ diffusion. When the tailored SEI-Zn is applied into aqueous systems, the hydrogen evolution and Zn corrosion are significantly suppressed, whilst a dendrite-free Zn deposition with a preferred (002) orientation is characterized. The presence of SEI enables a prolonged lifespan of symmetric Zn//Zn cells over 2500 and 450 h at 1.0 and 10.0 mA cm−2, respectively, significantly outperforming the bare Zn counterpart. Moreover, both coin- and pouch- type SEI-Zn//V2O5·nH2O full batteries exhibit excellent cycling durability. This work will inspire the design of SEI on metal anodes for stable aqueous batteries.