Nanoengineering of NiO/MnO[sub.2]/GO Ternary Composite for Use in High-Energy Storage Asymmetric Supercapacitor and Oxygen Evolution Reaction

• Published in: Nanomaterials (Basel, Switzerland) Switzerland), 2022-12, Vol.13 (1)
• Main Authors: Arshad, Natasha, Usman, Muhammad, Adnan, Muhammad, Ahsan, Muhammad Tayyab, Rehman, Mah Rukh, Javed, Sofia, Ali, Zeeshan, Akram, Muhammad Aftab, Demopoulos, George P, Mahmood, Asif
• Format: Article
• Language: English
• Subjects: Composite materials; Electric properties; Graphene; Mechanical properties; Nickel compounds; Oxides
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano13010099

Designing multifunctional nanomaterials for high performing electrochemical energy conversion and storage devices has been very challenging. A number of strategies have been reported to introduce multifunctionality in electrode/catalyst materials including alloying, doping, nanostructuring, compositing, etc. Here, we report the fabrication of a reduced graphene oxide (rGO)-based ternary composite NiO/MnO[sub.2] /rGO (NMGO) having a range of active sites for enhanced electrochemical activity. The resultant sandwich structure consisted of a mesoporous backbone with NiO and MnO[sub.2] nanoparticles encapsulated between successive rGO layers, having different active sites in the form of Ni-, Mn-, and C-based species. The modified structure exhibited high conductivity owing to the presence of rGO, excellent charge storage capacity of 402 F·g[sup.−1] at a current density of 1 A·g[sup.−1] , and stability with a capacitance retention of ~93% after 14,000 cycles. Moreover, the NMGO//MWCNT asymmetric device, assembled with NMGO and multi-wall carbon nanotubes (MWCNTs) as positive and negative electrodes, respectively, exhibited good energy density (28 Wh·kg[sup.−1] ), excellent power density (750 W·kg[sup.−1] ), and capacitance retention (88%) after 6000 cycles. To evaluate the multifunctionality of the modified nanostructure, the NMGO was also tested for its oxygen evolution reaction (OER) activity. The NMGO delivered a current density of 10 mA·cm[sup.−2] at the potential of 1.59 V versus RHE. These results clearly demonstrate high activity of the modified electrode with strong future potential.