The enhanced properties of ZnCoNi-S electrode by magnetron sputtering of Au nanoparticles for high performance supercapacitors

In this work, the distinctive effect of Au nanoparticles on shape preservation and properties enhancement during the preparation of transition metal sulfides is explored for the first time. After zeolitic imidazolate framework-67 (ZIF-67) is uniformly covered on nickel foam (NF), ZnCo layered double hydroxides (ZnCo-LDH) are compounded with ZIF-67 via hydrothermal method. The surface of compound is then coated with Au by magnetron sputtering. The final electrode is produced through sulfidation reaction. Benefiting from the excellent inertness and electrical conductivity of Au, the flake structure remains stable during the following sulfidation, and transfer impedance of the obtained Au/ZnS@Co3S4@Ni3S2 (Au/ZCN-S) electrode decreases significantly. In contrast, magnetron sputtered Ag or Cu nanoparticles react to Ag2S or CuS2 and cannot protect the refined structure of electrode as Au does. The Au/ZCN-S electrode shows a low transfer impedance of 0.0785 Ω and enables a specific capacity of 302.6 mAh g−1. Furthermore, the asymmetric supercapacitor constructed by Au/ZCN-S and activated carbon (AC) achieves a remarkable energy density of 104.09 Wh kg−1 with a high capacitance retention rate of 91.184 % after 10000 cycles. This work provides a new approach to optimize the morphology and performance of transition metal sulfides electrode for supercapacitors. [Display omitted] •Inert Au can effectively reduce the morphology damage caused by sulfidation.•Deposited Au can decrease transfer impedance and improve stability of electrode.•Au/ZCN-S//AC/CC possesses a superior energy density of 104.09 Wh kg−1.