NiSe2 nanocrystals intercalated rGO sheets as a high-performance asymmetric supercapacitor electrode

There is a growing demand for renewable and sustainable energy conversion and storage devices with the exhaustion of fossil fuels and increasing environmental contamination. In this paper, nickel diselenide (NiSe2) structures wrapped with various rGO (4%, 8%, 16%, and 32%) weight ratios were fabricated using a simple hydrothermal method and their structural, morphological, and electrochemical characteristics were studied systematically. The electrochemical properties of NiSe2/rGO with varying rGO concentrations were studied, and their supercapacitive performance was evaluated. NiSe2-16% rGO electrode outperformed NiSe2-32% rGO, NiSe2-8% rGO, and NiSe2-4% rGO due to its interconnected network topology and decreased effect of volume expansions. Moreover, during electrochemical activities, the optimum NiSe2-16% rGO electrode exhibited a high specific capacitance (1845.5 F g(-1) at 1.5 A g(-1)), excellent cycling stability (99.4% over 5000 cycles), and rapid ion/electron transit. An asymmetric supercapacitor with NiSe2-16% rGO as anode and activated carbon as cathode exhibited a high energy density of 12.66 Wh kg- at 3999.84 W kg(-1) and 99% retention of capacitance after 8000 repeated cycles. Our results have successfully demonstrated that the fabricated asymmetric super-capacitor has potential applications in the energy storage field.

Automated summary

With the depletion of fossil fuels and increasing environmental contamination, there is a growing demand for renewable and sustainable energy conversion and storage devices. In this study, nickel diselenide (NiSe2) structures wrapped with various rGO weight ratios were fabricated and their structural, morphological, and electrochemical characteristics were systematically studied. The NiSe2-16% rGO electrode exhibited superior supercapacitive performance, high specific capacitance, excellent cycling stability, and rapid ion/electron transit. An asymmetric supercapacitor with NiSe2-16% rGO as anode showed a high energy density and retained 99% of capacitance after 8000 repeated cycles.