Regulation of the surface morphology of CoNiSe2 by magnetron sputtering of Au nanoparticles for the property-promotion of electrode materials for high-performance supercapacitors

In this paper, the role of magnetron sputtered Au nanoparticles in regulating morphology of CoNiSe 2 to improve the performance of electrode materials for the supercapacitors is studied for the first time. After nanoneedle-like Co(OH) 2 is grown on Ni foam using a hydrothermal method, followed by Au nanoparticle deposition via magnetron sputtering. The resulting material underwent solvothermal processing with ascorbic acid as a reducing agent to prepare CoNiSe 2 . Because of the Au deposition, the morphology is changed by regulating the relationship between the ion consumption rate during selenization and the ion transport rate on the surface. When the magnetron sputtering time is 10 s, uniform mace-like CoNiSe 2 (named as NCA10-S) is formed with the best performance. Its specific capacitance reaches up to 2068.3 F g −1 at 1 A g −1 , which is 122.93 % higher than that of the single CoNiSe 2 electrode. The asymmetric supercapacitor composed of NCA10-S achieves a specific capacitance of 263.1 F g −1 at 1 A g −1 . When the power density reaches 800.01 W kg −1 , it has an energy density of 93.56 Wh kg −1 . This work provides a method for controlling transition metal selenide surface morphology to improve energy storage performance in supercapacitor electrodes.