In situ nitrogen-doped carbon nano-onions for ultrahigh-rate asymmetric supercapacitor. (20th January 2020)

• Record Type: Journal Article
• Authors: Mohapatra, Debananda; Muhammad, Olvianas; Sayed, Mostafa Saad; Parida, Smrutiranjan; Shim, Jae-Jin
• Is Part Of: Electrochimica acta. Volume 331(2020)
• Publication Date: 2020-01-20
• Subjects: Exohedral -- Graphitization -- Ultrahigh-rate asymmetric supercapacitor -- Negative electrode -- Rapid response; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.135363
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: The growing demand for clean energy storage and delivery during surge power applications motivate us to synthesize highly graphitic, mesoporous nitrogen-doped carbon nano-onions (N–CNOs) via a one-step in situ flame pyrolysis procedure for their potential asymmetric supercapacitor (ASC) electrodes. The operating voltage of the fabricated ASC device is extended to 1.8 V in a 1 M Na2 SO4 electrolyte, yielding a maximum specific capacitance of 113 F g −1 and a high energy density of 51 Wh kg −1 at a current density of 4 A g −1 . Importantly, even at a high current density of 20 A g −1, the device still delivers a high power density of 18 kW kg −1 while maintaining an energy density of 6 Wh kg −1 . Furthermore, the novel ASC exhibits excellent electrochemical cyclic stability over 10, 000 cycles, retaining 98% of its specific capacitance and excellent coulombic efficiency of 99% at a high current density of 20 A g −1 . The smaller characteristic relaxation time-constant (340 ms) than the previously reported graphene/MXene-based supercapacitors, validates the ultrahigh-rate ASC device-performance. These results confirm that N–CNOs can be used as a novel alternative electrode material in supercapacitors with high specific energy and power. Graphical abstract: Image 1 Highlights: Graphitic N–CNOs were prepared from acetonitrile by in situ one-step flame method. N–CNO//NiO ASC device presents a high energy density and high power density. ASC device shows excellent cycling stability and coulombic efficiency at 20 A g −1 . ASC device with a short response time shows ultrahigh-rate performance.