A Dual Active Site Organic–Inorganic Poly(O‐Phenylenediamine)/NH4V3O8 Composite Cathode Material for Aqueous Zinc‐Ion Batteries

Abstract

AbstractAqueous zinc‐ion batteries, considered one of the important candidate technologies for green and environmentally friendly large‐scale energy storage, hinge upon the performance of cathode materials as the key factor driving their development. Vanadate oxide is a promising cathode material due to its high theoretical capacity; furthermore, in order to accelerate the reaction kinetics, ion or molecular intercalation is often utilized. However, non‐electrochemically active intercalants tend to cause capacity degradation. In this study, a one‐step hydrothermal method is employed to intercalate electrochemically active poly‐o‐phenylenediamine (PoPDA) into the interlayers of NH4V3O8 (NVO), with graphene oxide (GO) being used to further improve the conductivity of the composite material (NVO/PoPDA@GO). The insertion of PoPDA expands the interlayer spacing of the NVO, alters the charge distribution, and enhances the migration rate of Zn2+ among the hybrid materials. Additionally, PoPDA serves as a support within the interlayers, improving the material stability. Moreover, the reversible transformation and rearrangement of chemical bonds (C═N/C─N) in PoPDA allows for coordination with Zn2+, providing additional capacity. As a result, NVO/PoPDA@GO exhibits excellent electrochemical performance, releasing a specific capacity of 433 mAh g−1 at 0.5 A g−1, even with a capacity of 224 mAh g−1 at 5 A g−1. This work provides a promising direction for the preparation of organic–inorganic composite cathode materials with dual active components.