In Situ Induced Core-Shell Carbon-Encapsulated Amorphous Vanadium Oxide for Ultra-Long Cycle Life Aqueous Zinc-Ion Batteries

Inevitable dissolution in aqueous electrolytes, intrinsically low electrical conductivity, and sluggish reaction kinetics have significantly hampered the zinc storage performance of vanadium oxide-based cathode materials. Herein, core-shell N-doped carbon-encapsulated amorphous vanadium oxide arrays, prepared via a one-step nitridation process followed by in situ electrochemical induction, as a highly stable and efficient cathode material for aqueous zinc-ion batteries (AZIBs) are reported. In this design, the amorphous vanadium oxide core provides unobstructed ions diffusion routes and abundant active sites, while the N-doped carbon shell can ensure efficient electron transfer and greatly stabilize the vanadium oxide core. The assembled AZIBs exhibit remarkable discharge capacity (0.92 mAh cm(-2) at 0.5 mA cm(-2)), superior rate capability (0.51 mAh cm(-2) at 20 mA cm(-2)), and ultra-long cycling stability (approximate to 100% capacity retention after 500 cycles at 0.5 mA cm(-2) and 97% capacity retention after 10 000 cycles at 20 mA cm(-2)). The working mechanism is further validated by in situ X-ray diffraction combined with ex situ tests. Moreover, the fabricated cathode is highly flexible, and the assembled quasi-solid-state AZIBs present stable electrochemical performance under large deformations. This work offers insights into the development of high-performance amorphous vanadium oxide-based cathodes for AZIBs.

Automated summary

Here, the authors report on the synthesis of core-shell N-doped carbon-encapsulated amorphous vanadium oxide arrays as a stable and efficient cathode material for aqueous zinc-ion batteries (AZIBs). The amorphous vanadium oxide core provides unobstructed ions diffusion routes and active sites, while the N-doped carbon shell ensures efficient electron transfer and stabilizes the vanadium oxide core. The fabricated AZIBs exhibit high discharge capacity, superior rate capability, and long cycling stability.