Microwave rapid fabrication of cerium/cobalt nickel sulfide electrode materials for high performance supercapacitors

In this work, a novel electrode materials of cerium/cobalt nickel sulfide (Ce/CoNi2S4) was synthesized by a one-step microwave approach. The Ce doping effect has been an efficient method to increase the rate properties and specific capacitance of the supercapacitor. When the current density is 1 A g−1, the specific capacitance of the CoNi2S4 electrode is 1988 F g−1, but when a small amount of rare earth (cerium nitrate hexahydrate) was doped, the optimized Ce/CoNi2S4 electrode exhibits a great specific capacitance of 2408 F g−1 at 1 A g−1 and excellent cycling stabilities (86% retention after 10000 cycles and 71% retention after 20000 cycles). In addition, the Ce/CoNi2S4 nanoflower shows excellent performance for aqueous asymmetric supercapacitor, and the energy density is as high as 70.4 Wh kg−1 when the power density is 750 W kg−1, and 52.1 Wh kg−1 when the power density is 7500 W kg−1. The Ce/CoNi2S4 electrode materials were synthesized by household microwave oven, which can not only realize the simple and efficient synthesis of materials, but also can realize the improvement of the properties of sulfide materials. This rare earth doped sulfide is a new concept in the synthesis design, and can also be apply to the synthesis of other materials, which has a certain guiding effect on the improvement of the performance of electrode materials in supercapacitors.