Graphene-like Vanadium Oxygen Hydrate (VOH) Nanosheets Intercalated and Exfoliated by Polyaniline (PANI) for Aqueous Zinc-Ion Batteries (ZIBs)

Abstract

A new approach is employed to boost the electrochemical kinetics and stability of vanadium oxygen hydrate (VOH, V2O5·nH2O) employed for aqueous zinc-ion battery (ZIB) cathodes. The methodology is based on electrically conductive polyaniline (PANI) intercalated–exfoliated VOH, achieved by preintercalation of an aniline monomer and its in situ polymerization within the oxide interlayers. The resulting graphene-like PANI–VOH nanosheets possess a greatly boosted reaction-controlled contribution to the total charge storage capacity, resulting in more material undergoing the reversible V5+ to V3+ redox reaction. The PANI–VOH electrode obtains an impressive capacity of 323 mAh g–1 at 1 A g–1, and state-of-the-art cycling stability at 80% capacity retention after 800 cycles. Because of the facile redox kinetics, the PANI–VOH ZIB obtains uniquely promising specific energy–specific power combinations: an energy of 216 Wh kg–1 is achieved at 252 W kg–1, while 150 Wh kg–1 is achieved at 3900 W kg–1. Electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) analyses indicate that with PANI–VOH nanosheets, there is a simultaneous decrease in the charge transfer resistance and a boost in the diffusion coefficient of Zn2+ (by a factor of 10–100) vs the VOH baseline. The strategy of employing PANI for combined intercalation–exfoliation may provide a broadly applicable approach for improving the performance in a range of oxide-based energy storage materials.

Polyaniline Encapsulated Amorphous V2O5 Nanowire‐Modified Multi‐Functional Separators for Lithium–Sulfur Batteries

“…[ 51,52 ] However, these peaks have shifted and became weaker in the VOH@PANI nanowires due to the interactions between the VOH nanowires and PANI species. [ 44 ] Consequently, the above Raman results give supporting evidence for the successful synthesis of the VOH@PANI nanowires.…”

“…Whereas an additional 11.5% weight loss that occurred above 400 °C is assigned to the decomposition of PANI. [ 44 ] Therefore, the weight ratio of PANI in the VOH@PANI nanowires can be calculated to be around 11.5%.…”

“…[ 58 ] Furthermore, the binding energy of V 5+ in V2p 3/2 is blue‐shifted to 517.3 eV for VOH@PANI, indicating the electron transfer between PANI and vanadium atoms. [ 44 ] Figure 2f shows the N1s XPS spectrum of the VOH@PANI, and three peaks locate at 398.5, 399.6, and 400.5 eV correspond to quinonoid imine (N), benzenoid imine (NH), and protonated amine (NH + ), respectively. [ 59 ] Importantly, the peak at 402.1 eV can be assigned to the protonated imine species (NH 2+ ) caused by intrachain doping of hydrochloric acid on PANI.…”

The Current Developments and Perspectives of V2O5 as Cathode for Rechargeable Aqueous Zinc‐Ion Batteries

“…Based on the aforementioned discussion, introducing water molecules and PANI between the layers of V 2 O 5 (PANI‐V 2 O 5 · n H 2 O) at the same time can further enhance the electrochemical performance by synergistically exerting their respective advantages. [ 49,50 ] However, water molecules and large molecular weight of PANI will occupy the zinc ion diffusion channels and structural water may cause the material to dissolve, so the impact of the amount of molecules on performance and structure needs further exploration.…”

Aqueous Rechargeable Zn‐ion Batteries: Strategies for Improving the Energy Storage Performance

“…also serve the purpose of the spacer between the two adjacent layers of vanadium oxide-based materials. [225][226][227][228][229] The in situ intercalation of PANI in between the layer of V 2 O 5 widen the interlayer spacing and block the electrostatic interaction between charge carrier Zn 2 + and the host material, favoring facile diffusion of Zn 2 + ion. The DFT analysis showed that the PANI intercalation causes the Fermi level to move towards the conduction band and facilitates the charge transfer.…”