Interface-Engineered Graphene/Copper Pyrovanadate Cathodes with V–O–C Bonds for Zinc-Ion Storage

Poor electronic conductivity and structural instability of vanadium-based oxides significantly limit their Zn 2+ storage performance. Herein, a graphene-modified copper pyrovanadate (Cu 3 V 2 O 7 (OH) 2 ·2H 2 O, denoted as CVOHG) was synthesized via a one-step hydrothermal route to address these limitations. The introduction of graphene effectively regulated the nanosheet morphology, induced interfacial V–O–C bonds, and constructed a continuous electron transport network. These interfacial interactions not only enhanced structural integrity but also facilitated charge transfer and Zn 2+ diffusion. Consequently, CVOHG delivered a reversible capacity approximately 2.5 times higher than that of pristine CVOH, together with improved cycling stability (148 mAh g –1 at 200 mA g –1 after 200 cycles), and reduced charge-transfer resistance. This study highlights a simple yet effective interfacial-engineering approach to designing high-performance metal oxide/carbon composites, offering valuable insights into the development of advanced Zn-ion battery cathodes.