Synchronous organic-inorganic co-intercalated ammonium vanadate cathode for advanced aqueous zinc-ion batteries

Vanadium-based cathode materials are attractive for aqueous zinc-ion batteries (AZIBs) owing to the high capacity from their open frameworks and multiple valences. However, the cycle stability and rate capability are still restricted by the low electrical conductivity and trapped diffusion kinetics. Here, we propose an organic-inorganic co-intercalation strategy to regulate the structure of ammonium vanadate (NH4V4O10, NVO). The introduction of Al3+ and polyaniline (PANI) induces the optimized layered structure and generation of urchin-like hierarchical construction (AP-NVO), based on heterogeneous nucleation and dissolution-recrystallization growth mechanism. Owing to these favorable features, the AP-NVO electrode delivers a desirable discharge capacity of 386 mA h g-1 at 1.0 A g-1, high-rate capability of 263 mA h g-1 at 5.0 A g-1 and excellent cycling stability with 80.4% capacity retention over 2000 cycles at 5.0 A g-1. Such satisfactory electrochemical performance is believed to result from the enhanced reaction kinetics provided by the stable layered structure and a high intercalation pseudo-capacitance reaction. These results could provide enlightening insights into the design of layered vanadium oxide cathode materials.