3D Porous Urchin-like NH4V3O8·2H2o Microspheres Constructed for High-Performance and Long-Life Rechargeable Aqueous Zinc Ion Battery

Abstract

As one of the promising alternative energy storage systems, aqueous-based rechargeable zinc-ion batteries have received continuous attention owing to their high abundance, cost effectiveness, and high safety. However, the development of suitable cathode materials with superior electrochemical performances are severely hampered by the unstable structural property during Zn2+ intercalation/deintercalation, and the sluggish kinetics of Zn2+ with divalent charge into the host structure. In the present work, a highly reversible aqueous Zn2+ battery is first demonstrated in aqueous electrolyte by employing 3D porous urchin-like NH4V3O8·2H2O microspheres assembled from ultrathin nanowires as cathode materials. Benefiting from the synthetic merits of the unique 3D porous architecture, it can provide numerous accessible channels for fast kinetics of Zn2+, short diffusion path for Zn2+ migration, and promote the rapid transfer of electrons. As a result, the NH4V3O8·2H2O microspheres cathode exhibits excellent electrochemical performances with a high reversible capacity of 415 mAh g-1 at 0.2 A g-1, superior rate capability, and durable cycling stability with a capacity retention of 80% after 2000 cycles under the high current density of 10 A g-1. Our result demonstrates that such porous NH4V3O8·2H2O microspheres cathode material is a potential candidate for the high performance rechargeable aqueous zinc-ion battery. Furthermore, the quasi-solid-state NH4V3O8·2H2O/Zn battery shows high potential for flexible energy storage systems.