A Water Based Synthesis of Ultrathin Hydrated Vanadium Pentoxide Nanosheets for Lithium Battery Application: Free Standing Electrodes or Conventionally Casted Electrodes?

- Facile water based synthesis of V2O5·nH2O nanosheets.
- Operando XRD study to follow up the synthesis of V2O5·nH2O nanosheets.
- Simple method to fabricate flexible and free standing electrodes (FSE).
- Significant improvement in the accessible capacity for lithium-ion intercalation in FSE.

Ultrathin hydrated vanadium pentoxide (V2O5·nH2O) nanosheets are fabricated via a water based exfoliation technique. The exfoliation process involves reflux of the precursor, 1:4 mixture of VO2 and V2O5, in water at 80 °C for 24 h. Operando and ex situ X-ray diffraction (XRD) studies are conducted to follow the structural changes during the exfoliation process. The chemical and thermal analyses suggest that the molecular formula of the nanosheet is H0.2V1.8VV0.2IVO5⋅0.5H2O. The V2O5·nH2O nanosheets are mixed with 10% of multi-walled carbon nanotube (MW-CNT) to form a composite material assigned as (VOx-CNT). Free standing electrodes (FSE) and conventionally casted electrodes (CCE) of VOx-CNT are fabricated and then tested as a positive electrode material for lithium batteries. The FSE shows reversible capacities of 300 and 97 mAhg-1 at current densities of 10 and 200 mAhg-1, respectively. This is better than earlier reports for free-standing electrodes. The CCE delivers discharge capacities of 175 and 93 mAhg-1 at current densities of 10 and 200 mAhg-1, respectively.

Ultrathin V2O5·nH2O nanosheets are prepared via a facile one-step water based exfoliation technique. Operando XRD is used to track the structural changes during the exfoliation process. A composite material from the V2O5·nH2O nanosheets and 10% of multi-walled carbon nanotube (MW-CNT) is fabricated and shows a promising capacity and rate capabilities for lithium battery application.116