Flexible reduced graphene oxide/prussian blue films for hybrid supercapacitors

Flexible prussian blue/reduced graphene oxide (PB/rGO) nanocomposite films are fabricated by an in situ interfacial strategy. Metallic iron foil provides a solid support for efficacious reduction of graphene oxide, and in turn, the in situ release of ferrous ions facilitate a simultaneous formation of PB nanocubes anchoring tightly onto the conductive rGO. The flexible PB/rGO film exhibits excellent flexibility and hierarchically porous architecture, thus yielding a strong synergistic effect of enlarged electro-active interfaces, fast ion/electron transport kinetics, and remarkable mechanical stability. The binder-free electrode manifests a high specific capacitance of 286 F g⁻¹ in the Na₂SO₄ aqueous electrolyte and superior rate/cycling performance. Hybrid cells based on the PB/rGO show an extended working potential window of 2.0 V, a specific energy/power of 45.4 Wh kg⁻¹/20.1 kW kg⁻¹, and a long-term lifespan. The present work will shed light on the development of flexible electrode materials toward high-performance supercapacitor applications.