▎ 摘　　要

Nickel ferrite (NiFe2O4) is a promising material for electrochemical supercapacitors among many metal ferrites. However, the low specific capacitance of NiFe2O4 limits its application. We present a new high-performance supercapacitor based on a nanocomposite material of NiFe alloy-graphene nanosheets (NiFe-A@GNS). We prepared NiFe2O4 nanoparticles using a simple liquid fusion method and used as a catalyst substrate for the chemical vapor deposition (CVD) synthesis of NiFe-A@GNS nanocomposite material. According to the XRD, TEM, SEM and Raman results, high-quality, crystalline, and graphitized GNS was successively composited with NiFe-A nanoparticles. Therefore, both pristine NiFe2O4 and the new composite material were evaluated as electrodes for supercapcitors. In the case of NiFe-A@GNS nanocomposite, we report a 3.2-fold increase in specific capacitance (845 F g 1) when compared to the pristine NiFe2O4 (264 F g (1)). Furthermore, after 5000 cycles, the NiFe-A@GNS electrode retains 94.3% of its capacity, making it more stable than the NiFe2O4 electrode (62% after 2000 cycles). At 1.0 A g(-1) current density, the NiFe-A@GNS device has a high energy density (30.8 Wh kg(-1)) and a high power density (620 W kg(-1)). The synergistic effects of NiFe-A and graphene nanosheets, as well as the excellent surface characteristics, are the keys to the high performance of NiFe-A@GNS electrodes. Our design offers a promising method for developing high-performance supercapacitor devices.