In Situ Constructing Flexible V2O5@GO Composite Thin Film Electrode for Superior Electrochemical Energy Storage

In this work, uniform wrinkle V2O5@GO flexible thin films have been successfully synthesized via a facile drop-casting and annealing process from the composite sol-gel. It is found that VG8 composite thin film with an appropriate mass ratio (8:1) of V2O5 and GO shows an outstanding specific capacitance of 397 F g−1 at a current density of 1 A g−1, high-class rate capability (77%) and good cycling stability with 98% capacitance retention over 2000 cycles at a current density of 5 A g−1, which is much superior than pure V2O5 thin film electrode. A full solid-state symmetric energy storage device is assembled using the VG8 composite thin film, exhibiting high energy density of 17.66 Wh kg−1 at a power density of 249.9 W kg−1, as well as excellent cycling stability (89.3% capacitance retention after 5000 cycles). Impressively, three charged device in series can light up a yellow light emitting diodes (LEDs), demonstrating its potential in futher energy storage applications.