Manifesting the Carrier Behavior of a Vanadium Oxide/Carbon Composite Cathode in Aqueous Zinc-Ion Batteries

In the development of aqueous zinc-ion batteries (AZIBs), carbon materials have received significant interest as supporting materials for vanadium-based oxides. To improve the performance of AZIBs, in this study, amorphous V 2 O 5 embedded carbon nanofiber composites (a-V 2 O 5 @NCNFs) are constructed by an electrostatic spinning technique. The uniformly embedded structure of a-V 2 O 5 in carbon nanofibers not only endows an excellent electrical conductivity and structural stability but also effectively inhibits vanadium dissolution in the aqueous electrolyte. Furthermore, the presence of carbon on the a-V 2 O 5 surface creates important effects on the intercalation of Zn 2+ and H + . Specifically, the nitrogen-doped carbon on the a-V 2 O 5 surface increases the intercalation of H +, which is beneficial to maintain the structural stability of a-V 2 O 5 @NCNFs. Consequently, an optimized a-V 2 O 5 @NCNFs-4 cathode exhibits excellent rate performance with the discharge specific capacity of 196 mAh g –1 at 21 A g –1 and a long cycling life with the capacity retention of 87.3% at 5 A g –1 after 5000 cycles. This study gained further insights into the energy storage mechanism of vanadium oxide/carbon composite cathodes.