Vanadium hexacyanoferrate nanoparticles connected by cross-linked carbon nanotubes conductive networks for aqueous zinc-ion batteries

Prussian blue analogues (PBAs) have attracted increasing attention in the field of aqueous zinc-ion batteries (AZIBs) with the advantages of an open framework with adjustable valence and easy synthesis. However, due to the disadvantages of unstable structure and insufficient active sites, PBAs as cathode materials for AZIBs still have problems such as low specific capacity or poor cycle performance. In this work, a simple in-situ co-precipitation method is used to grow vanadium hexacyanoferrate (VHCF) nanoparticles on carbon nanotubes (CNTs), which aims to improve the conductivity of electrode materials by introducing a conductive skeleton of CNTs. This hybrid structure of VHCF nanoparticles and CNTs promotes electron transport between VHCF nanoparticles, thereby effectively improving the utilization of the material. Benefiting from the inherent sufficient channels for ions insertion/extraction of VHCF and the excellent conductivity of CNTs, the VHCF/CNTs hybrid as AZIBs cathode material shows excellent zinc storage performance with a high reversible capacity of 97.8 mAh g−1 at 50 mA g−1 and a discharge specific capacity of 52.7 mAh g−1 after 1000 cycles at 3200 mA g−1. This work provides a new idea for the design of high-performance PBAs-based cathodes for AZIBs.