High-Performance Wide-Temperature Zinc-Ion Batteries with K/CN Co-Intercalated Ammonium Vanadate Cathodes.

NHVO (NVO) is considered a promising cathode material for aqueous zinc-ion batteries due to its high theoretical capacity. However, its practical application is limited by irreversible deamination, structural collapse, and sluggish reaction kinetics during cycling. Herein, K and CN co-intercalated NVO (KNVO-CN) nanosheets with expanded interlayer spacing are synthesized for the first time to achieve high-rate, stable, and wide-temperature cathodes. Molecular dynamics and experimental results confirm that there is an optimal CN content to achieve higher reaction kinetics. The synergistic effect of K and CN co-intercalation significantly reduces the electrostatic interaction between Zn and the [VO] layer, improves the specific capacity and cycling stability. Consequently, the KNVO-CN electrode displays outstanding electrochemical performance at room temperature and under extreme environments. It exhibits excellent rate performance (228.4 mAh g at 20 A g), long-term cycling stability (174.2 mAh g after 10,000 cycles at 20 A g), and power/energy density (210.0 Wh kg at 14,200 W kg) at room temperature. Notably, it shows remarkable storage performance at - 20 °C (111.3 mAh g at 20 A g) and 60 °C (208.6 mAh g at 20 A g). This strategy offers a novel approach to developing high-performance cathodes capable of operating under extreme temperatures.