Zinc-ion
batteries have gained considerable attention owing to
their cost-effectiveness, high energy density, and environmental friendliness
compared with lithium-ion batteries. However, the development of suitable
electrolytes and active materials remains a challenge that must be
addressed. In this study, for the first time, Keggin bicapped-type
polyoxovanadate KxH9(PV14O42) (KPV) was used as the active material for
zinc-ion batteries. Owing to the multiple vanadium and oxygen atoms
in KPV, the structure can accommodate and provide a fast kinetic reaction
to store Zn2+, thus benefiting from a highly reversible
capacity of 413.3 mAh g–1 and high energy and power
densities of 348.8 Wh kg–1 and 42.15 kW kg–1, respectively, and maintaining a Coulombic efficiency of nearly
97.96% after 2000 cycles. In addition, the fabricated cell was subjected
to critical temperature testing ranging from −20 to 40 °C
and the results showed a remarkably high reversible capacity of 375.5
mAh g–1 (0.5 A g–1) at 40 °C.
This highlights the potential for designing active materials for high-energy
storage devices.