Electronic Structure Regulation of Layered Vanadium Oxide via Interlayer Doping Strategy toward Superior High-Rate and Low-Temperature Zinc-Ion Batteries

Currently, development of suitable cathode materials for zinc-ion batteries (ZIBs) is plagued by the sluggish kinetics of Zn2+ with multivalent charge in the host structure. Herein, it is demonstrated that interlayer Mn2+-doped layered vanadium oxide (Mn0.15V2O5 center dot nH(2)O) composites with narrowed direct bandgap manifest greatly boosted electrochemical performance as zinc-ion battery cathodes. Specifically, the Mn0.15V2O5 center dot nH(2)O electrode shows a high specific capacity of 367 mAh g(-1) at a current density of 0.1 A g(-1) as well as excellent retentive capacities of 153 and 122 mAh g(-1) after 8000 cycles at high current densities up to 10 and 20 A g(-1), respectively. Even at a low temperature of -20 degrees C, a reversible specific capacity of 100 mAh g(-1) can be achieved at a current density of 2.0 A g(-1) after 3000 cycles. The superior electrochemical performance originates from the synergistic effects between the layered nanostructures and interlayer doping of Mn2+ ions and water molecules, which can enhance the electrons/ions transport kinetics and structural stability during cycling. With the aid of various ex situ characterization technologies and density functional theory calculations, the zinc-ion storage mechanism can be revealed, which provides fundamental guidelines for developing high-performance cathodes for ZIBs.