Heterostructure of MnSe2@NiCo2Se4 as novel electrode material for high-performance asymmetric supercapacitors

For high-performance electrochemical energy storage and conversion applications, controllable nanoarchitecture arrays of the transition metal selenide on conductive substrates are attractive electrode materials. In this work, a heterostructure comprising of MnSe2 nanorods over NiCo2Se4 nanosheets with a large specific surface area is rationally generated on nickel foam (NF) substrate (MnSe2@NiCo2Se4) using a hydrothermal process. The formation mechanism of the MnSe2@NiCo2Se4 heterostructure was also examined by adjusting the selenium feeding during the selenization process. The MnSe2@NiCo2Se4-2 electrode exhibits remarkable capacitance (1078C g−1 at 1 A g−1), and superior cycle stability (90.7 % after 8000 cycles) as a result of the cooperative effect of MnSe2 and NiCo2Se4. Furthermore, an asymmetric supercapacitor (ASC) was developed employing the improved MnSe2@NiCo2Se4-2 and activated carbon materials (AC) as the positive electrode and negative electrode (MnSe2@NiCo2Se4-2//AC), respectively, which has a high energy density of 63.2 Wh kg−1 at a power density of 396 W kg−1. The impressive performance indicates that the MnSe2@NiCo2Se4 electrode has a bright potential in supercapacitors.