Simple solvothermal synthesis of porous graphene-NiO nanocomposites with high cyclic stability for supercapacitor application

• Published in: Journal of alloys and compounds Vol. 854; p. 157190
• Main Authors: Sethi, Meenaketan, Shenoy, U. Sandhya, Bhat, D. Krishna
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.02.2021; Elsevier BV
• Subjects: Capacitance; Composite materials; Current density; Cyclic stability; Electrode materials; Electrodes; Energy storage; Graphene; Nanocomposite; Nanocomposites; Nickel oxides; NiO nanoflakes; Porous graphene; Sheets; Specific capacitance; Supercapacitor; Supercapacitors; Synthesis; Cyclic stability; Supercapacitor; Specific capacitance; Porous graphene; Nanocomposite; NiO nanoflakes
• DOI: 10.1016/j.jallcom.2020.157190
• ISSN: 0925-8388

Over the years supercapacitors have established themselves as energy storage devices as well as a subject to reckon with. Thus, not surprisingly tremendous effort has been put in the field of supercapacitor research. However, a device with all desirable characteristics has not yet been realized and hence deserves to be paid utmost heed. Herein, we report a facile synthesis of porous graphene-NiO (PGNO) nanocomposites via a unique mixed solvent system through a solvothermal approach. The microscopic characterization of porous graphene (PG) reveals the presence of pores in the graphene sheets, NiO (NO) shows flake like structure and PGNO composite displays the anchoring of NO nanoflakes on the PG sheets. A series of electrode materials were prepared by varying the percentage composition of PG and the materials were named as 5–30 PGNO, respectively. The electrochemical study represented a good capacitance value of 511.0 F g−1 at a scan rate of 5 mV s−1 for the 10 PGNO composite in a 3-electrode method and 80% retention of initial capacitance after 10,000 cycles at a current density of 8 A g−1. The fabricated symmetrical hybrid supercapacitor by using the 10 PGNO electrodes also depicted a good capacitance value of 86.0 F g−1 at a scan rate of 5 mV s−1. The fabricated device retained 84% of initial capacitance at the end of 10,000 cycles at a current density of 8 A g−1, demonstrating the good electrochemical strength and rate capability of the material. The percentage of double layer capacitance and pseudocapacitance contributions to the overall specific capacitance of the PGNO supercapacitor has also been estimated. Overall, the results exhibited by the composite material warrants its beneficial utility in energy storage devices. [Display omitted] •Simple solvothermal synthesis of porous graphene-NiO nanocomposite.•Use of unique mixed solvent system for the solvothermal synthesis.•Nanocomposite exhibits good specific capacitance, high rate capability along with high cyclic stability.•The material would be a potential candidate for supercapacitor application.