Performance of Solid-state Hybrid Energy-storage Device using Reduced Graphene-oxide Anchored Sol-gel Derived Ni/NiO Nanocomposite

Abstract

The influence of (nickel nitrate/citric acid) mole ratio on the formation of sol-gel end products was examined. The formed Ni/NiO nanoparticle was anchored on to reduced graphene-oxide (rGO) by means of probe sonication. It was found that the sample obtained from the (1:1) nickel ion: citric acid (Ni2+: CA) mole ratio resulted in a high specific capacity of 158 C/g among all (Ni2+: CA) ratios examined. By anchoring Ni/NiO on to the rGO resulted in enhanced specific capacity of as high as 335 C/g along with improved cycling stability, high rate capability and Coulombic efficiency. The high conductivity and increased surface area seemed responsible for enhanced electrochemical performances of the Ni/NiO@rGO nanocomposite. A solid-state hybrid energy-storage device consisting of the Ni/NiO@rGO (NR2) as a positive electrode and the rGO as negative electrode exhibited enhanced energy and power densities. Lighting of LED was demonstrated by using three proto-type (NR2 (+)|| rGO(−)) hybrid devices connected in series.

Disposed Dry Cells as Sustainable Source for Generation of Few Layers of Graphene and Manganese Oxide for Solid‐State Symmetric and Asymmetric Supercapacitor Applications

“…This is usually reported for a supercapacitor electrode due to the rapid surface reaction on the electrode surface. The specific capacitance of the graphene and the MnO 2 electrodes was calculated from the charge/discharge profiles using the following formula: …”

“…The asymmetric device was fabricated using the graphene as negative electrode and the MnO 2 as positive electrode with (PVA: H 2 SO 4 ) gel‐electrolyte. The gel‐electrolyte (PVA: H 2 SO 4 ) was prepared as per our previous reports . The cyclic voltammograms and the galvanostatic charge‐discharge profiles of the symmetric device (MnO 2 |PVA:H 2 SO 4 |MnO 2 ) were recorded at different potential windows.…”

“…On the other hand, metal‐oxides or hydroxides such as RuO 2 , NiO, Co 3 O 4 , Ni(OH) 2 , Co(OH) 2 etc. are also examined as electroactive material for supercapacitor application . Among them, MnO 2 having high theoretical capacitance of 1370 F g −1 , has been largely exploited as electrode material due to its promising pseudocapacitive nature .…”

Large exchange bias and enhanced coercivity in strongly-coupled Ni/NiO binary nanoparticles

“…These factors are critical especially in nanosized crystals and are strongly affected by the synthetic route. Remarkable progress has been made in recent years regarding the synthesis of the Ni/NiO binary manoparticles., 10,12,[17][18][19][20] Highly crystalline and monodisperse Ni/NiO nanoparticles have been prepared by the physical techniques including laserinduced reductive sintering, 3 sequential layer deposition, 10 CVD method, 21 nanosecond laser irradiation, 22 cluster-beam deposition, 23 and pulsed laser deposition. 24 However, universal agreement of the origin of the EB effect and other related anomalous magnetic properties is still under debate.…”

“…24 However, universal agreement of the origin of the EB effect and other related anomalous magnetic properties is still under debate. In addition the chemical synthesis methods of Ni/NiO nanoparticles are under development for instance, sol-gel route, 20,25,26 solution-combustion synthesis, 27,28 chemical reduction method, 12,18,29 solvothermal/thermal treatment process, 30 thermal decomposition, 31,32 electrodeposition technique, 4,17 etc. These chemical methods could be used for effective control of microstructures but the correlation between microstructural parameters and magnetic properties has not yet been studied systematically.…”