NiFe₂O₄ nanoparticles on reduced graphene oxide for supercapacitor electrodes with improved capacitance

Spinel transition metal oxides are regarded as one of the finest pseudocapacitive materials, while unexpected stability hinders their practical application. For addressing such issue, herein, we use a simple hydrothermal method to grow NiFe₂O₄ nanoparticles on the surface of reduced graphene oxide (rGO). The rGO nanosheets in the hybrid can be used as a conductive substrate to accelerate the movement of electrons and ions, and they can also inhibit the aggregation of NiFe₂O₄. As the electrochemically active materials, the NiFe₂O₄ nanoparticles can reduce the self-stacking of rGO as well as increase the pseudocapacitance. The rGO-NiFe₂O₄ hybrid delivers improved specific capacitance of 215.7 F g^-1 at 0.5 A g^-1, and exhibits superior cycle stability with no obvious capacity loss after 10000 cycles. Our work demonstrates a method for effectively improving the electrochemical performance of NiFe₂O₄, and accelerating the commercialization of transition metal oxides as electrode materials for supercapacitors.