Ni@NiO Nanowires on Nickel Foam Prepared via “Acid Hungry” Strategy: High Supercapacitor Performance and Robust Electrocatalysts for Water Splitting Reaction

Abstract

Ni/NiO core-shell nanowires on nickel foam (NF) are successfully synthesized using an "acid-hungry" strategy. The 3D electrode with large accessible active sites and improved conductivity, possesses an optimized ionic and electronic transport path during electrochemical processes. High areal capacitance of 1.65 F cm is obtained at an ultrahigh current density of 100 mA cm , which is 19.88 times higher than pristine NF. The direct growth of nanowires makes the present supercapacitor electrode robust for long-term cycling test. By virtue of the favorable hydrogen adsorption energies on Ni and OH energy on NiO or NiOOH, the 3D electrode exhibits high performance in hydrogen evolution reaction with 146 mV at η10 mA cm-2 and Tafel value of 72 mV dec , and oxygen evolution reaction with 382 mV at η10 mA cm-2 and Tafel value of 103 mV dec in 1 m KOH. An electrolyzer using 3D electrodes as both anode and cathode can yield a current density of 10 mA cm at 1.71 V, and possesses superior long-term stability to an electrolyzer consisting of Pt/C||Ir/C. The present work develops an effective and low-cost method for the large-scale fabrication of Ni/NiO core-shell nanowires on commercial NF, providing a promising candidate for supercapacitors, fuel cells, and electrocatalysis.

In Situ Growth of Hierarchical Ni‐Mn‐O Solid Solution on a Flexible and Porous Ni Electrode for High‐Performance All‐Solid‐State Asymmetric Supercapacitors

“…[47] Notably,t he CV curve of the 3D-Ni/Ni-Mn-O electrode shows one more reduction peak at approximately 0.32 V, which may result from the 3D-Ni substrate due to the high-temperature annealing of the 3D Ni(OH) 2 /Ni foam. [48,49] The integrated area of the CV curve of the 3D-Ni/Ni-Mn-O electrode is much larger than those of the other electrodes, indicating its superiora realcapacitance. Figure 4b shows the galvanostatic charge/discharge (GCD) curveso ft he three electrodes at ac urrent density of 2mAcm À2 within ap otential window of 0-0.6 V. The 3D-Ni/Ni-Mn-O electrode delivers am uch longer discharge time than the other two electrodes, indicating ah ighera real capacitance.…”

“…At a scan rate of 30 mV s −1 within the potential window of 0–0.6 V, the redox peaks of Ti‐foil/Ni 0.75 Mn 0.25 O/C (Ti‐F/Ni‐Mn‐O), Ni‐foam/Ni 0.75 Mn 0.25 O/C (Ni‐F/Ni‐Mn‐O), and 3D‐Ni/Ni 0.75 Mn 0.25 O/C (3D‐Ni/Ni‐Mn‐O) are 0.55/0.35, 0.56/0.34, and 0.51/0.22 V versus the standard calomel electrode (SCE), respectively, corresponding to a pseudocapacitive response of M‐O/M‐O‐O‐H (M represents Ni and Mn ions) arising from reversible Faradaic reactions as shown in their CV curves (Figure a) . Notably, the CV curve of the 3D‐Ni/Ni‐Mn‐O electrode shows one more reduction peak at approximately 0.32 V, which may result from the 3D‐Ni substrate due to the high‐temperature annealing of the 3D Ni(OH) 2 /Ni foam . The integrated area of the CV curve of the 3D‐Ni/Ni‐Mn‐O electrode is much larger than those of the other electrodes, indicating its superior areal capacitance.…”

Heterojunction α-Co(OH)2/α-Ni(OH)2 nanorods arrays on Ni foam with high utilization rate and excellent structure stability for high-performance supercapacitor

“…The rapid consumption of non-renewable energy resources and the booming development of mobile electronics and hybrid electric vehicle have aroused intensive attention on green and safe energy storage devices with high specific capacitance and excellent working life 1–5 . Supercapacitors as emerging energy storage devices combine the advantages of conventional capacitors and batteries and possess the high-power density, long cycle life, fast charge/discharge performance, safe reliability and environmentally friendly at the same time, resulting in the explosive-growth attention of researchers 6–10 .…”

Constructing Earth‐abundant 3D Nanoarrays for Efficient Overall Water Splitting – A Review

“…For overall water splitting in 1.0 M KOH, Zhao et al . have observed that NiMo−Cu nano array on Cu foam with core‐shell structure (NiMo as shell and Cu nanowire array as core) exhibits enhanced activity (1.61 V at 10 mA cm −2 ) and stability (12 h), while Sun et al . have observed that Ni−NiO nano array with core‐shell structure on Ni foam exhibits enhanced activity (1.71 V at 10 mA cm −2 ) and stability (20 h).…”