Bullet-like microstructured nickel ammonium phosphate/graphene foam composite as positive electrode for asymmetric supercapacitors. Issue 28 (24th April 2020)

• Record Type: Journal Article
• Authors: Mahmoud, Badr A.; Mirghni, Abdulmajid A.; Fasakin, Oladepo; Oyedotun, Kabir O.; Manyala, Ncholu
• Is Part Of: RSC advances. Volume 10:Issue 28(2020)
• Page Start: 16349
• Page End: 16360
• Publication Date: 2020-04-24
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra02300k
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Unique morphology of (Ni(NH4 )2 (PO3 )4 ·4H2 O/60GF) as a positive electrode for high-performance asymmetric supercapacitors. Abstract : Unique microstructured nickel ammonium phosphate Ni(NH4 )2 (PO3 )4 ·4H2 O and Ni(NH4 )2 (PO3 )4 ·4H2 O/GF composite were successfully synthesized through the hydrothermal method with different graphene foam (GF) mass loading of 30, 60 and 90 mg as a positive electrode for asymmetric supercapacitors. The crystal structure, vibrational mode, texture and morphology of the samples were studied with X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET) surface area analysis and scanning electron microscopy (SEM). The prepared materials were tested in both 3-and 2-electrode measurements using 6 M KOH electrolyte. The composite material Ni(NH4 )2 (PO3 )4 ·4H2 O/60 mg exhibited a remarkable gravimetric capacity of 52 mA h g −1, higher than the 34 mA h g −1 obtained for the Ni(NH4 )2 (PO3 )4 ·4H2 O pristine sample, both at 0.5 A g −1 . For the fabrication of the asymmetric device, activated carbon from pepper seed (ppAC) was used as a negative electrode while Ni(NH4 )2 (PO3 )4 ·4H2 O/60 mg GF was adopted as the positive electrode. The Ni(NH4 )2 (PO3 )4 ·4H2 O/60 mg GF//ppAC asymmetric device delivered a specific energy of 52 Wh kg −1 with an equivalent specific power of 861 W kg −1 at 1.0 A g −1 within a potential range of 0.0–1.5 V. Moreover, the asymmetric device displayed a capacity retention of about 76% for over 10 000 cycles at a high specific current of 10.0 A g −1 .