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.

Graphical abstractUltrathin 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.Download high-res image (116KB)Download full-size image