Vanadium dopant induced the small and low crystallinity layered MnO2 supported on the carbon Nanosheets for high-performance aqueous zinc-ion batteries

Manganese dioxide (MnO 2 ), with its high theoretical capacity, environmental benignity, and low cost, is a promising cathode material for aqueous zinc-ion batteries (ZIBs). Nevertheless, its practical application is hindered by sluggish electrochemical kinetics and poor electrical conductivity. Herein, we report a facile synthesis of Vanadium (V) doping MnO 2 supported on carbon nanosheets (CN) with reduced crystallinity and nanoscale dimensions (V-MnO 2 /CN). The CN substrate not only enhances the conductivity but also provides abundant nucleation sites for the uniform growth of MnO 2 nanosheets. The incorporation of V regulates the electronic structure of MnO 2 , lowers its crystallinity, and generates plentiful oxygen vacancies. These structural and compositional synergies enhance electronic conductivity, accelerate ion diffusion, and expose more electrochemically active sites. As a result, the prepared V-MnO 2 /CN cathode delivers a high specific capacity of 352.9 mAh g −1 at 0.5 A g −1 and excellent cycling stability with 83.2 % capacity retention after 1000 cycles at 1 A g −1 . Further ex-situ analysis reveals that the charge storage mechanism is governed by reversible Zn 2+ /H + co-insertion and extraction. This study provides a simple yet effective design principle for constructing low crystallinity, heteroatom-doped MnO 2 nanosheets for high-performance and durable ZIBs cathodes.