Tuning Interlayer and Mixed Vanadium Valences of V2O5 via Organic and Inorganic Guests Co-Intercalation Enables Boosted Aqueous Zinc-Ion Storage

Aqueous zinc-ion batteries (AZIBs) have gained great attention due to their nontoxicity, low-cost, and high theoretical capacity. However, the scarcity of suitable cathode materials with excellent performance limits the practical application of AZIBs. Herein, we develop a conducting polymer (polyaniline) and divalent ions (Ca 2+ ) co-intercalated method to synergistically regulate the property of V 2 O 5 to enhance Zn 2+ storage performance. The synergistic effect of co-insertion Ca 2+ and polyaniline (PANI) not only enlarges the interlayer spacing but also regulates multiple oxidation states of vanadium, which dramatically improves the conductivity, diffusion kinetics, and structural stability of host V 2 O 5 . Consequently, the resultant Ca/PANI/V 2 O 5 •nH 2 O (CPVO) as AZIBs cathodes exhibits extraordinary specific capacity of 512 mAh g –1 (0.5 A g –1 ) and cycling stability with an outstanding coulombic efficiency of around 100% after 2000 cycles (25 A g –1 ). Moreover, the Zn 2+ storage mechanism is elaborated by combining comprehensive characterizations and DFT calculations.