Constructing an asymmetric supercapacitor based on Prussian blue analogues-derived cobalt selenide nanoframeworks and iron oxide nanoparticles

Prussian blue (PB) and Prussian blue analogues (PBA) have the advantages of 3D open framework, large specific surface area, and controllable pore distribution, but poor conductivity and stability when used as electrodes. Nonetheless, it can be transformed into nanostructured metal oxides and chalcogenides based on their unique nanostructure to achieve good cycle life and high capacity retention. Herein, PB/PBA-derived Co 0.85 Se nanoframeworks (Co 0.85 Se NFs) and Fe 2 O 3 nanoparticles (Fe 2 O 3 NPs) have been prepared by a facile in-situ complex-precipitation and subsequent selenization/oxidation processes. Thanks to their unique nanostructure, large specific capacity and complementary operating voltage, a novel Co 0.85 Se//Fe 2 O 3 asymmetric supercapacitor (ASC) was assembled by using Co 0.85 Se NFs as positive electrode and Fe 2 O 3 NPs as negative electrode, respectively. The Co 0.85 Se//Fe 2 O 3 ASC delivers a wide output potential of 1.6 V, acceptable energy density of 18.9 Wh kg −1 at a high-power density of 800 W kg −1 , as well as good cycling durability of 89% capacitance retention after 3000 cycles. These results indicate that metal compounds prepared from Prussian blue analogs as self-templates are promising electrode materials and potential for practical applications in energy storage fields.