Ferrocene Preintercalated Vanadium Oxides with Rich Oxygen Vacancies for Ultrahigh Rate and Durable Zn-Ion Storage

The vanadium oxides with classical high-capacity materials as well as high operating voltage have been regarded as appealing electrodes for aqueous zinc-ion batteries (AZIBs) owing to their multiple valences and adjustable ion-diffusion channels. However, the developed AZIBs cathodes have always suffered from sluggish Zn2+ diffusion kinetics and less stable layered structure, thus resulting in the inadequate electrochemical performance. In this work, unique organometallic (ferrocene) reintercalated inorganic (vanadium oxide) cathodes (Fec/Od-VO) with defective crystal structure were firstly synthesized via a redox intercalation method for ultrahigh-rate and ultralong-life aqueous ZIBs. The unique organometallic can not only enlarge interlayer distances between the V-O layers, with expediting channels for fast Zn2+ diffusion, but also introduce the rich oxygen vacancies to facilitate the surface reversible Zn2+ adsorption. The resulting Fec/Od-VO displays a high discharge capacity (411.7 mAh g−1 at 0.5 A g−1) and superior long-term cycling stability (86.5% retention over 3000 cycles at 20 A g−1). This enlightened design combining interlayer regulation with oxygen defect engineering proves to be a new modus operand toward advanced AZIBs by redox intercalation of unique organometallic.