Preparation and characterization of Ni-based positive electrodes for use in aqueous electrochemical capacitors

Coating Current Collector Surface with Ni–Al Layered Double Hydroxide by Liquid Phase Deposition to Reduce Charge-Transfer Resistance

“…[1][2][3] Recently, the use of an NiAl layered double hydroxide (LDH) as the cathode material in Ni-MH batteries has attracted attention because of its structural stability and good electrochemical properties. [4][5][6][7] At present, B-Ni(OH) 2 is widely used as the Ni positive active material in alkaline storage batteries.…”

NiO layers grown on a Ni substrate by galvanostatic anodization as a positive electrode material for aqueous hybrid capacitors

“…4b). The specific power of 19 kW kg À1 for the anodized Ni HC was substantially higher than that of 1 kW kg À1 for the Ni foam cell [6]. Fig.…”

“…In our previous research, the NiO active material was deposited on a Ni sheet and foam substrates by chemical bath deposition, and the HC cells with the NiO-loaded Ni foam positive electrodes showed a specific discharge capacitance of 88 F g À1 at 1 mA, which was calculated from the mass of the positive and negative active materials [6]. Because the mass of the Ni foam substrate was about 10-fold that of the NiO active material [6], the specific energy per total mass of positive and negative electrodes was about 2 W h kg À1 . In contrast, the HC cell with the anodized Ni positive electrode after potential cycling showed a high specific energy of 16 W h kg À1 , because the pristine Ni metal sheet used in this study was a lightweight current collector (Fig.…”

“…The NiO electrode has a large oxygen overpotential [6]. We have previously constructed hybrid capacitors (HCs) using a NiO positive electrode and an activated carbon (AC) negative electrode, and they exhibited high specific power and specific energy [6,7].…”

“…We have previously constructed hybrid capacitors (HCs) using a NiO positive electrode and an activated carbon (AC) negative electrode, and they exhibited high specific power and specific energy [6,7]. However, the NiO active materials were loaded on Ni foam and mesh substrates which meant the specific energy was too low for practical applications.…”