Enhancing lithium/sodium-ion storage behaviors in a V2O5 nanosheet by freeze-drying

A porous V2O5 nanosheet is synthesized via freeze-drying followed by a heat-treatment process. Observably, transmission electron microscopy and atomic force microscopy analysis indicate that a porous and thin layer microstructure is achieved with V2O5. Electrochemical measurement demonstrates that the as-obtained V2O5 exhibits evident advantage toward the sodium/lithium ion storage. When evaluated as a cathode for sodium ion batteries, the V2O5 nanosheet delivers an initial discharge capacity of 199.8 mA h g(-1). Even after 200 cycles at 50 mA g(-1), the V2O5 nanosheet can retain a capacity of 123.9 mA h g(-1), which is 2.3 times higher than that of bulk V2O5. Cyclic voltammetry and electrochemical impedance spectroscopy analysis further confirm that this rationally-designed porous nanosheet can increase the electroactive sites for the redox reaction and shorten the pathway of charge transfer, consequently leading to an enhanced capacitive sodium ion storage behavior.

Automated summary

A porous V2O5 nanosheet was synthesized using freeze-drying and heat-treatment processes, showing excellent performance in sodium/lithium ion storage.