Organic Intercalation Induced Kinetic Enhancement of Vanadium Oxide Cathodes for Ultrahigh-Loading Aqueous Zinc-Ion Batteries

Vanadium-based oxides have attracted much attention because of their rich valences and adjustable structures. The high theoretical specific capacity contributed by the two-electron-transfer process (V⁵⁺/V³⁺) makes it an ideal cathode material for aqueous zinc-ion batteries. However, slow diffusion kinetics and poor structural stability limit the application of vanadium-based oxides. Herein, a strategy for intercalating organic matter between vanadium-based oxide layers is proposed to attain high rate performance and long cycling life. The V₃O₇·H₂O is synthesized in situ on the carbon cloth to form an open porous structure, which provides sufficient contact areas with electrolyte and facilitates zinc ion transport. On the molecular level, the added organic matter p-aminophenol (pAP) not only plays a supporting role in the V₃O₇·H₂O layer, but also shows a regulatory effect on the V⁵⁺/V⁴⁺ redox process due to the reducing functional group on pAP. The novel composite electrode with porous structure exhibits outstanding reversible specific capacity (386.7 mAh g⁻¹, 0.1 A g⁻¹) at a high load of 6.5 mg cm⁻², and superior capacity retention of 80% at 3 A g⁻¹ for 2100 cycles.