Interlayer Modification of Pseudocapacitive Vanadium Oxide and Zn(H O) Migration Regulation for Ultrahigh Rate and Durable Aqueous Zinc-Ion Batteries.

The interlayer modification and the intercalation pseudocapacitance have been combined in vanadium oxide electrode for aqueous zinc-ion batteries. Intercalation pseudocapacitive hydrated vanadium oxide Mn V O ·12H O with defective crystal structure, interlayer water, and large interlayer distance has been prepared by a spontaneous chemical synthesis method. The inserted Mn forms coordination bonds with the oxygen of the host material and strengthens the interaction between the layers, preventing damage to the structure. Combined with the experimental data and DFT calculation, it is found that Mn refines the structure stability, adjusts the electronic structure, and improves the conductivity of hydrated vanadium oxide. Also, Mn changes the migration path of Zn , reduces the migration barrier, and improves the rate performance. Therefore, Mn -inserted hydrated vanadium oxide electrode delivers a high specific capacity of 456 mAh g at 0.2 A g , 173 mAh g at 40 A g , and a capacity retention of 80% over 5000 cycles at 10 A g . Furthermore, based on the calculated zinc ion mobility coefficient and Zn(H O) diffusion energy barrier, the possible migration behavior of Zn(H O) in vanadium oxide electrode has also been speculated, which will provide a new reference for understanding the migration behavior of hydrated zinc-ion.