Synthesis and electrochemical properties of hydrangea-like (NH4)2V4O9/V5O12•6H2O cathode for zinc-ion battery

Energy density, power density, as well as the cost of aqueous zinc-ion batteries (AZIBs), are largely determined by the cathode material. Among the various cathodic candidates, vanadium-based materials with various oxidation states of vanadium cations and open frameworks have emerged as highly promising options. In this work, a heterogeneous with hydrangea-like (NH4)(2)V4O9/V5O12 & BULL;6H(2)O as cathode materials for AZIBs. The hydrogen bonds formed by NH4+ of (NH4)(2)V4O9, in conjunction with the lattice water in V5O12 & BULL;6H(2)O, sufficiently strengthen the cohesion of the layered structure and expand the interlayer space. As a result, accelerating the diffusion of Zn2+ ultimately leads to an enhanced overall discharge capacity. Remarkably, the hydrangea-like (NH4)(2)V4O9/V5O12 & BULL;6H(2)O electrode at a current density of 100 mA g(-1) shows a high reversible capacity of 209 mAh g(-1) after 150 cycles and higher rate capability (172 mAh g(-1) at 500 mA g(-1)). The outstanding electrochemical performance can be attributed to the unique structure of the cathode material and accelerated diffusion coefficient of Zn2+.