Structural coupling of Mg-intercalated bilayer and monolayer V₂O₅ for high-stability and high-capacity aqueous...

To address the critical challenge of balancing structural stability and high capacity in vanadium-based cathodes for aqueous zinc-ion batteries (ZIBs), we propose a rational design strategy based on the structural coupling of Mg-intercalated bilayer V₂O₅ (MVO) and monolayer V₂O₅, collectively referred to as C-MVO. The C-MVO cathode is synthesized through a facile Polytetrafluoroethylene (PTFE) assisted sonochemical approach followed by controlled thermal annealing. This unique architecture synergistically integrates enhanced stability of MVO with abundant active sites of V₂O₅. The C-MVO cathode achieves a high capacity of 518.9 mAh g^-1 (0.1 A g^-1), with 89.2% retention after 1000 cycles (1.0 A g^-1). Comprehensive interfacial kinetic analysis reveals significantly reduced activation energy barriers for Zn²⁺ desolvation at the solid-liquid interface (55.7 kJ mol^-1) and solid-state diffusion (19.2-24.4 kJ mol^-1) compared to pristine V₂O₅. Ex-situ characterizations confirm highly reversible Zn²⁺ (de)intercalation and robust structural integrity. This work establishes a paradigm for designing high-stability, high-capacity ZIB cathodes through targeted structural hybridization, coupled with a scalable and energy-efficient synthesis route, paving the way for practical applications.