Rational Design of High‐Performance Electrodes Based on Ferric Oxide Nanosheets Deposited on Reduced Graphene Oxide for Advanced Hybrid Supercapacitors

Abstract The core strategy for constructing ultra‐high‐performance hybrid supercapacitors is the design of reasonable and effective electrode materials. Herein, a facile solvothermal‐calcination strategy is developed to deposit the phosphate‐functionalized Fe 2 O 3 (P‐Fe 2 O 3 ) nanosheets on the reduced graphene oxide (rGO) framework. Benefiting from the superior conductivity of rGO and the high conductivity and fast charge storage dynamics of phosphate ions, the synthesized P‐Fe 2 O 3 /rGO anode exhibits remarkable electrochemical performance with a high capacitance of 586.6 F g −1 at 1 A g −1 and only 4.0% capacitance loss within 10 000 cycles. In addition, the FeMoO 4 /Fe 2 O 3 /rGO nanosheets are fabricated by utilizing Fe 2 O 3 /rGO as the precursor. The introduction of molybdates successfully constructs open ion channels between rGO layers and provides abundant active sites, enabling the excellent electrochemical features of FeMoO 4 /Fe 2 O 3 /rGO cathode with a splendid capacity of 475.4 C g −1 at 1 A g −1 . By matching P‐Fe 2 O 3 /rGO with FeMoO 4 /Fe 2 O 3 /rGO, the constructed hybrid supercapacitor presents an admirable energy density of 82.0 Wh kg −1 and an extremely long working life of 95.0% after 20 000 cycles. Furthermore, the continuous operation of the red light‐emitting diode for up to 30 min demonstrates the excellent energy storage properties of FeMoO 4 /Fe 2 O 3 /rGO//P‐Fe 2 O 3 /rGO, which provides multiple possibilities for the follow‐up energy storage applications of the iron‐based composites.