The 3D Flower–Like MnV12O31·10H2O as a High‐Capacity and Long‐Lifespan Cathode Material for Aqueous Zinc‐Ion Batteries

Abstract

Selecting the right cathode material is a key component to achieving high‐energy and long‐lifespan aqueous zinc‐ion batteries (AZIBs); however, the development of cathode materials still faces serious challenges due to the high polarization of Zn2+. In this work, MnV12O31·10H2O (MnVO) synthesized via a one‐step hydrothermal method is proposed as a promising cathode material for AZIBs. Because the stable layered structure and hieratical morphology of MnVO provide a large layer space for rapid ion transports, this material exhibits high specific capacity (433 mAh g−1 at 0.1 A g−1), an outstanding long‐term cyclability (5000 cycles at a current density of 3 A g−1), and an excellent energy density (454.65 Wh kg−1). To illustrate the intercalation mechanism, ex situ X‐Ray diffraction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy are adopted, uncovering an H+/Zn2+ dual‐cation co‐intercalation processes. In addition, density‐functional theory calculation analysis shows that MnVO has a delocalized electron cloud and the diffusion energy barrier of Zn2+ in MnVO is low, which promotes the Zn2+ transport and consequently improves the reversibility of the battery upon deep cycling. The key and enlightening insights are provided in the results for designing high‐performance vanadium‐oxide‐based cathode materials for AZIBs.

Keywords

• aqueous Zn-ion batteries
• high reversibility
• MnV12O31·10H2O
• vanadate
• Zn2+/H+ hybrid storage mechanism