One-step solvothermal synthesis of heterostructured nanocomposite Ni0.85Se/MnSe as the high-performance electrode material for supercapacitors

A facile one-step solvothermal method is developed to prepare heterostructured nanocomposite Ni0.85Se/MnSe. High-resolution transmission microscopy confirms the formation of the heterostructure. When coated onto carbon cloth and used as the electrode material for supercapacitors, the electrode with the optimized Ni0.85Se/ MnSe exhibits specific capacity of 1118 Cg(-1) at the current density of 1 Ag-1, and a capacity retention at 83.2% after 5000 charge-discharge cycles at 10 Ag-1 in 4 M KOH using three-electrode system. The assembled asymmetric supercapacitor exhibits the specific energy of 49.3 Wh kg(-1) at the power density of 799.81 W kg(-1), and 97.8% of the initial capacity is retained after 5000 charge-discharge cycles at 5 Ag-1. Kinetic study indicates that the major contribution of the capacity is the diffusion-controlled process, and the electrode exhibits batterytype behavior. The excellent charge storage performance is originated from the higher number of electrochemically active sites, improved reaction kinetics and facilitated diffusion that are induced by the charge redistribution at the heterostructure interface. Conversion of the surface metal selenides to oxides and (oxy) hydroxides is observed during the long-term charge-discharge cycling. The heterostructured nanocomposite Ni0.85Se/MnSe is a promising candidate as the electrode material for supercapacitors.

Automated summary

A facile one-step solvothermal method is developed to prepare heterostructured nanocomposite Ni0.85Se/MnSe, which exhibits high specific capacity and capacity retention in supercapacitors. The excellent charge storage performance is attributed to the formation of the heterostructure, which results in improved reaction kinetics and facilitated diffusion.