Ultrathin nanosheets of cobalt-nickel hydroxides hetero-structure via electrodeposition and precursor adjustment with excellent performance for supercapacitor

Chemical Modifications of Layered Double Hydroxides in the Supercapacitor

“…d) The preparation schematic of H-3DRG@NiCo-LDH and H-3DRG@NiCo 2 S 4 (H-3DRG: heteroatom-doped edgeenriched 3D rivet graphene), SEM images of e) H-3DRG@NiCo-LDH and f) 3DRG@NiCo 2 S 4 . [99] Copyright 2018, Royal Society of Chemistry. g) The preparation mechanism of CoNi-alloy and CoNi-alloy@CoNi-sulfides, h) XRD pattern of CoNi-LDH, CoNi-R and CoNi-R-S, SEM image of i) CoNi-LDH and j) CoNi-S, k) the total and partial electronic density of CoNi-S and CoNi-O.…”

“…3D NiFe-LDH / 1061 F g À1 @ 1 A g À1 56.4% @ 1-10 A g À1 80% after 1000 cycles@5 A g À1 [87] CiNo-LDH Ni foam 1587.5 F g À1 @ 0.5 A g À1 72.8% @ 0.5-10 A g À1 91.5% after 1000 cycles at 5 A g À1 [88] NiCo-LDH GO 1489 F g À1 @ 1 A g À1 68%@ 1-100 A g À1 80% after 5000 cycles at 6 A g À1 [30] Phase transformation NiCoFe-Ni@FG Ni foam 2110 F g À1 @ 1 A g À1 87.2%@ 1-20 A g À1 97.6% after 5000 cycles at 10 A g À1 [118] NiCoP Ni foam 2143 F g À1 @ 1 A g À1 75.4% @ 1-20 A g À1 73% after 3000 cycles at 10 A g À1 [105] H-3DRG @NiCo 2 S 4 nanoporous copper 217.5 mAh g À1 @ 0.5 A g À1 85% @ 1-50 A g À1 90% after 10 000 cycles [99] NiV-LDH-S Ni foam 2270.4 F g À1 @ 2 A g À1 51.3% @ 1-20 A g À1 91.9% after 10 000 cycles at 25 A g À1…”

“…The prepared 3D NiFe‐LDH microspheres show excellent electrocatalytic oxygen evolution reaction (OER) activity in the alkaline medium and good durability. Wei et al [ 88 ] used a mixture of cobalt nitrates and nickel acetates as the electrolyte and changed the molar ratio to obtain ultrathin (~5 nm) 2D nanosheets of CoNi LDHs. When the optimized Ni(OAc) 2 /Co(NO 3 ) 2 molar ratio is 0.64/0.36, the hybrid shows a very interesting feature—that the aggregates comprise different sizes of densely stacked tremella‐like structures (Figure 10c,d).…”

Urchin-Like Ni2/3Co1/3(CO3)1/2(OH)·0.11H2O for High-Performance Supercapacitors

“…The NC/rGO composite electrode could still retain ~94% of the initial capacity over 5,000 cycles at a high current density of 20 A g −1 , which is higher than the NC electrode (~88% of the initial capacity), revealing its good cycling stability (Figure 5e) . Furthermore, the cycling stability of the NC/rGO in 2 M aqueous KOH aqueous solution using a typical three-electrode cell were superior to many transition metal compounds electrode materials reported in literature, such as Co(OH) 2 nanosheets (89.1% capacitance retention after 5,000 cycles at 20 A g −1 ) (Chen et al, 2018b ), Co-doped α-Ni(OH) 2 /RGO nanosheet (87.9% capacitance retention after 1,000 cycles at 10 A g −1 ) (Zhang et al, 2018b ), Ni(OAc) 2 /Co(NO 3 ) 2 (91.5% capacitance retention after 1,000 cycles at 5 A g −1 ) (Wei et al, 2018 ), illustrating the excellent capacity and long-term electrochemical stability of the NC/rGO composite electrode.…”

Phase control of 2D binary hydroxides nanosheets via controlling-release strategy for enhanced oxygen evolution reaction and supercapacitor performances

“…They are found to have a number of increasing applications, ranging from electric vehicles to wearable devices [14,15] . Transition metal-based oxides and hydroxides, such as Co 3 O 4 , Co(OH) 2 , Ni(OH) 2 , NiO have been explored as active materials for positive electrodes due to their high specific capacitance [16][17][18][19] . Anyhow, various electrocatalytic materials, in principle, should offer both abundant active sites and rapid mass-diffusion pathways via exquisite controlling of the specific properties (morphologies, nano-channels, phases, etc.)…”