Organic functionalization engineering in vanadium-based cathodes toward advanced aqueous zinc-ion batteries

Vanadium-based materials have emerged as promising cathode candidates for aqueous zinc-ion batteries (AZIBs) due to their multivalent redox characteristics and diverse crystal structures, which enable high energy storage capacity. Nevertheless, practical applications are hindered by several critical challenges, including vanadium species dissolution, side-product formation, sluggish Zn2+ diffusion kinetics, and low electrical conductivity. Organic functionalization, benefiting from its structural tunability and abundant functional groups, has been proven to be an effective strategy for enhancing the electrochemical performance of vanadium-based cathodes. This review systematically summarizes recent advances in organic-functionalized vanadium-based cathodes. First, the energy storage mechanism of vanadium-based cathodes and the fundamental properties of organic compounds relevant to cathode optimization are outlined. Then, the functions of organic compounds are comprehensively analyzed from four key perspectives: capacity improvement, conductivity enhancement, Zn2+ diffusion kinetics optimization, and cycling stability promotion. Furthermore, the specific electrochemical performance modulation effects and practical application examples of this strategy are discussed in detail. Finally, current limitations and challenges in this field are highlighted, and corresponding solutions and future research directions are proposed, offering theoretical guidance and insights for the development of high-performance vanadium-based cathodes for AZIBs.