Hierarchical Porous Nickel Research Articles

A nanoporous nickel–iron alloy seamlessly anchored into hierarchical porous nickel for efficient and extremely stable water splitting

The development of a robust, low-cost electrode for electrochemical water splitting is a challenging, but essential task for realizing hydrogen production under industrial conditions. Here, we seamlessly anchor nanoporous nickel–iron into a hierarchical porous nickel foam (npNi–Fe/HPNF) by a designed gaseous oxidation–reduction engineering for a commercial nickel foam. The three-dimensional hierarchical porous structure considerably enhances the specific surface area of the electrode, yielding abundant electrocatalytic sites that promote the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Moreover, owing to its mechanically robust, seamlessly anchored architecture, and remarkable superhydrophilicity/superaerophobicity, the electrolyzer composed of self-standing npNi–Fe/HPNF and its electro-activation derivative displays a current density of 10 mA cm−2 at 1.54 V, ultralong durability of more than 2000 h at 500 mA cm−2 in a 1 M KOH electrolyte, and high performance of 2 V at 1 A cm−2 in a quasi-industrial environment (5 M KOH and 70 °C), outperforming most alkaline electrolyzers based on state-of-the-art electrodes. Exceptional electrochemical performance and the ability to be prepared at a large scale (2500 cm2) make npNi–Fe/HPNF a promising candidate for industrial water splitting applications.

Gas-Phase-Induced Engineering for Fabrication of 3D Hierarchical Porous Nickel and Its Application toward High-Performance Supercapacitors.

Commercial nickel foam (NF), which is composed of numerous interconnected ligaments and hundred-micron pores, is widely acknowledged as a current collector/electrode material for catalysis, sensing, and energy storage applications. However, the commonly used NF often does not work satisfactorily due to its smooth surface and hollow structure of the ligaments. Herein, a gas-phase-induced engineering, two-step gaseous oxidation-reduction (GOR) is presented to directly transform the thin-walled hollow ligament of NF into a three-dimensional (3D) nanoporous prism structure, resulting in the fabrication of a unique hierarchical porous nickel foam (HPNF). This 3D nanoporous architecture is achieved by utilizing the spontaneous reconstruction of nickel atoms during volume expansion and contraction in the GOR process. The process avoids the involution of acid-base corrosion and sacrificial components, which are facile, environmentally friendly, and suitable for large-scale fabrication. Furthermore, MnO2 is electrochemically deposited on the HPNF to form a supercapacitor electrode (HPNF/MnO2). Because of the fully open structure for ion transport, superhydrophilic properties, and the increased contact area between MnO2 and the current collector, the HPNF/MnO2 electrode exhibits a high specific capacitance of 997.5 F g-1 at 3 A g-1 and remarkable cycling stability with 99.6% capacitance retention after 20000 cycles in 0.1 M Na2SO4 electrolyte, outperforming most MnO2-based supercapacitor electrodes.

Hierarchical porous nickel tin sulfide nanosheets as a binder free electrode for hybrid supercapacitor

The utilization of free-standing sulfide-based hybrid nanostructures plays a paramount role in supplying the steadily increasing demand for energy storage devices. Herein, this report presents the growth of outstanding binder-free Ni-Sn sulfide thin films for high-performance supercapacitors via the revised successive ionic layer adsorption and reaction (r-SILAR) method. Molar concentration ratios between Ni/Sn have been studied, and the optimum designed mesoporous Nix-Sn1.0xS/Ni foam (NF), a single cathode electrode material, successfully achieved outstanding specific capacitance of 2890 F/g at 5 A/g, capacitance retention of 85 %, and coulombic efficiency of 100 % after 10,000 cycles. Moreover, the constructed Nix-Sn1.0xS/NF//activated carbon (AC) hybrid supercapacitor device delivers an ultrahigh power density of 53.469 KW/Kg and capacitance retention of 95 % with robust long-term cycling stability up to1000 cycles. The superior electrochemical performance of the prepared Nix-Sn1.0xS electrode could be attributed to: (i) the synergistic effect of the two binary metal sulfides (Ni/Sn) into reversible faradaic redox reaction; (ii) the growing mechanism of the ultra-thin film (1.2 nm) as a binder-free electrode, enhance the ions insertion/extraction, and (iii) the formation of hierarchically flower-like architecture with uniform mesopores provides a high surface area (62.2 m2/g) and intensifies active sites for faradaic redox reactions. These encouraging results present a novel avenue for constructing advanced free-standing electrode materials for high-performance supercapacitors.

Alkaline Ni-Zn Microbattery Based on 3D Hierarchical Porous Ni Microcathode with High-Rate Performance.

Miniaturized energy storage devices with superior performance and compatibility with facile fabrication are highly desired in smart microelectronics. Typical fabrication techniques are generally based on powder printing or active material deposition, which restrict the reaction rate due to the limited optimization of electron transport. Herein, we proposed a new strategy for the construction of high-rate Ni-Zn microbatteries based on a 3D hierarchical porous nickel (Ni) microcathode. With sufficient reaction sites from the hierarchical porous structure as well as excellent electrical conductivity from the superficial Ni-based activated layer, this Ni-based microcathode is featured with fast-reaction capability. By virtue of facile electrochemical treatment, the fabricated microcathode realized an excellent rate performance (over 90% capacity retention when the current density increased from 1 to 20 mA cm-2). Furthermore, the assembled Ni-Zn microbattery achieved a rate current of up to 40 mA cm-2 with a capacity retention of 76.9%. Additionally, the high reactivity of the Ni-Zn microbattery is also durable in 2000 cycles. This 3D hierarchical porous Ni microcathode, as well as the activation strategy, provides a facile route for the construction of microcathodes and enriches high-performance output units for integrated microelectronics.

All-Printed High-Performance Flexible Supercapacitors Using Hierarchical Porous Nickel–Cobalt Hydroxide Inks

All-Printed High-Performance Flexible Supercapacitors Using Hierarchical Porous Nickel–Cobalt Hydroxide Inks

Long-life and efficient sodium metal anodes enabled by a sodiophilic matrix

Sodium metal is a promising alternative anode for high-energy Na-based batteries due to its natural abundance, favorable redox voltage and remarkable theoretical capacity. However, unstable solid electrolyte interface (SEI) film, huge volume variation and uncontrolled Na dendrite growth, resulting in low Coulombic efficiency and limited span-life, have dragged the Na metal anode out of practical application. Herein, 3D hierarchical porous nickel foam matrix decorated by Fe2O3 nanosheets (Fe2O3 @Ni) is synthesized and served as a sodiophilic scaffold to reduce Na nucleation overpotential and achieve uniform Na deposition without dendrite growth. Consequently, the composite Na/Fe2O3 @Ni anode shows smaller hysteresis voltage at a high current density of 5 mA cm−2 and exhibits satisfactory cycling stability with a Coulombic efficiency of ~ 99.77% (up to 1000 cycles). When in couple with Na3V2(PO4)3 cathode, the full cell shows higher capacity and better cycling stability than the one with bare Na anode. The 3D porous nickel modified by Fe2O3 presents a new perspective for the anode design of sodium metal battery.

Three-dimensional NiCo2O4 nanosheets arrays on carbon nanofibers for high-performance asymmetric solid-state supercapacitor

A hybrid nanocomposite (NCO-CNF) with 3D hierarchical porous nickel cobalt-oxide (NCO) nanosheets structure was successfully constructed on the surface of the N-doped carbon nanofiber (CNF) through the combination of electrospinning, hydrothermal and heat-treatment process, where the CNF as a structural scaffold and excellent conductor to improve the conduction of electrons and effectively prevent aggregation of NCO-CNF nanosheets. Thus, generating a synergistic electrochemical enhancement through maximize utilization of two components and strong coupling interaction between 1D CNF and 2D NCO nanosheets. The resultant NCO-CNF delivered outstanding specific capacitance as high as 343 F g−1 in three electrode system. Furthermore, the obtained NCO-CNF can as the positive electrode while the CNF serves as the negative electrode to assemble the solid asymmetric supercapacitor and the energy density of NCO-CNF//CNF is up to 44.8 Wh kg−1 (44.8 μWh cm−2). This work leaves more strategies for utilizing effectively 2D nanomaterials and carbon fiber.

Synthesis of Hierarchical Porous Nickel Phyllosilicate Microspheres as Efficient Adsorbents for Removal of Basic Fuchsin

Synthesis of Hierarchical Porous Nickel Phyllosilicate Microspheres as Efficient Adsorbents for Removal of Basic Fuchsin

Three dimensional hierarchical porous nickel cobalt layered double hydroxides (LDHs) and nitrogen doped activated biocarbon composites for high-performance asymmetric supercapacitor

Nitrogen-doped activated biocarbon (AC) and nickel-cobalt layered double hydroxides (LDHs) composites (NixCo1−x LDH/AC) are prepared by solvothermal method at various Ni/Co molar ratios. 3D nanoflowers composed of LDH nanosheets are spontaneously grown on the surface of AC from bio-waste, providing a suitable structure for the diffusion and transport of electrolyte ions. Ni0.5Co0.5LDH/AC composite electrode has high specific capacitance of 947 F g−1 at the current density of 1 A g−1, which could be explained by the synergistic effect of LDHs and AC. Furthermore, symmetric coin-cell AC//Ni0.5Co0.5 LDH/AC supercapacitor is assembled using Ni0.5Co0.5 LDH/AC composite as the cathode, and the pristine AC as the anode. Within 1.6 V voltage range, the supercapacitor device shows a maximum capacitance values (Csc) of 112 F g−1 at 1 A g−1. The developed asymmetric supercapacitor exhibits excellent rate performance and good cycle stability reflected through the maintenance of 80% of the initial Csc after 5000 consecutive cycles. Moreover, high energy density (39.7 Wh kg−1) is observed at low power density of 0.8 kW kg−1, and maintained at relatively high value (22.2 Wh kg−1) at high power density (16 kW kg−1). All these data indicate the potential applicability of AC//Ni0.5Co0.5 LDH/AC asymmetric supercapacitor for energy storage.

Front Cover: Hierarchical Multiporous Nickel for Oxygen Evolution Reaction in Alkaline Media (ChemCatChem 24/2019)

The Front Cover shows the combination of macroporous and mesoporous features in a nickel layer is tested for the electrochemical oxygen evolution reaction. In their Full Paper, Chularat Wattanakit, Alexander Kuhn and co-workers obtain highly organized hierarchical porous nickel by combining a hard- and soft-template method to increase its electrocatalytic performance and stability during oxygen evolution reaction. This example illustrates a promising strategy for the rational design of high-performance porous metals, not only in the frame of water electrolysis, but also for other electrocatalytic applications. More information can be found in the Full Paper by Sunpet Assavapanumat et al. on page 5951 in Issue 24, 2019 (DOI: 10.1002/cctc.201901509).

Hierarchically porous nickel–cobalt phosphide nanoneedle arrays loaded micro-carbon spheres as an advanced electrocatalyst for overall water splitting application

Due to the easy recyclability and pollution-free nature of hydrogen fuel, its highly purified production through electrochemical water splitting process has been attracting increasing attention. In this work, a hybrid of hierarchical porous nickel–cobalt phosphide nanoneedle arrays supported micro-carbon spheres was successfully synthesized and employed as robust bifunctional electrocatalyst for overall water splitting. The optimized Ni1Co3–P@CSs displayed catalytic activity with a low overpotential (η) of 57 mV at 10 mA cm−2 for hydrogen evolution and a η of 330 mV at 20 mA cm−2 for oxygen evolution, along with good stability after testing for 30 h. The water splitting cell of the Ni1Co3–P@CSs delivered smaller cell voltage at a current density of 50 mA cm−2 and much better durability than a similar device based on RuO2/C and Pt/C. The enhanced performance was assumed to the unique hierarchical three-dimensional urchin nanostructure of bimetallic phosphide nanoneedles, which resulted in the synergetic effects to modulate electronic properties and electroactive surface area. These improved the reactant's intermediates adsorption energy, number of exposed active sites, and various shortened channels for charge transfer and reactant/electrolyte diffusion. Our finding offers an attractive electrocatalyst with low cost and high catalytic activity for efficient water electrolysis.

Hierarchical porous Nickel Cobaltate Nanotube as Electrocatalyst for Lithium-Oxygen Batteries

Hierarchical porous Nickel Cobaltate Nanotube as Electrocatalyst for Lithium-Oxygen Batteries

Fabrication of hierarchical porous nickel based metal-organic framework (Ni-MOF) constructed with nanosheets as novel pseudo-capacitive material for asymmetric supercapacitor

Hierarchical porous nickel based metal-organic framework (Ni-MOF) constructed with nanosheets is fabricated by a facile hydrothermal process with the existence of trimesic acid and nickel ions. Various structures of Ni-MOFs can be obtained through adjusting the molar ratio of trimesic acid and nickel ion, the obtained hierarchical porous Ni-MOF exhibits optimal porous structure, which also possesses largest specific surface area. The hierarchical porous structure constructed with nanosheets can supply more active sites for electrochemical reactions to realize the excellent electrochemical properties, thus the hierarchical porous Ni-MOF reveals an outstanding specific capacitance of 1057 F/g at current density of 1 A/g, and delivers high specific capacitance of 649 F/g at current density of 30 A/g, indicating that it exhibits good rate capability of 63.4% even up to 30 A/g. The hierarchical porous Ni-MOF keeps 70% of its original value up to 2 500 charge-discharge cycles at the current density of 10 A/g. Furthermore, asymmetric supercapacitors (ASCs) were assembled based on hierarchical porous Ni-MOF and activated carbon (AC), the ASCs reveal specific capacitance of 87 F/g at current density of 0.5 A/g, and exhibit high energy density of 21.05 Wh/kg and power density of 6.03 kW/kg. Additionally, the tandem ASCs can light up a red LED. The hierarchical porous Ni-MOF exhibits promising applications in high performance supercapacitors.

Hierarchical Porous Nickel Cobaltate Nanoneedle Arrays as Flexible Carbon-Protected Cathodes for High-Performance Lithium-Oxygen Batteries.

Rechargeable lithium-oxygen (Li-O2) batteries are consequently considered to be an attractive energy storage technology because of the high theoretical energy densities. Here, an effective binder-free cathode with high capacity for Li-O2 batteries, needle-like mesoporous NiCo2O4 nanowire arrays uniformly coated on the flexible carbon textile have been in situ fabricated via a facile hydrothermal process followed by low temperature calcination. Because of the material and structural features, the needle-like NiCo2O4 nanowire arrays (NCONWAs) served as a binder-free cathode exhibits high specific capacity (4221 mAh g(-1)), excellent rate capability, and outstanding cycling stability (200 cycles). This cathode based on nonprecious mesoporous metal oxides nanowire arrays has large open spaces and high surface area, providing numerous catalytically active sites and effective transmission pathways for lithium ion and oxygen, and promises the abundant Li2O2 storage. The fast electron transport by directly anchoring on the substrate ensures fast electrochemical reaction process involved with the every nanowire. Furthermore, a bendable Li-O2 battery assembled by using the flexible NCONWAs as the cathode, can be able to light an LED and shows good rate capability and cyclic stability.

Controllable synthesis of hierarchical porous nickel oxide sheets arrays as anode for high-performance lithium ion batteries

Customized hierarchical porous metal oxide arrays is of great importance for construction of high-performance electrochemical devices. In this work, we report hierarchical porous (HP)-NiO sheets arrays by a facile hydrothermal method. Interestingly, the obtained NiO sheets arrays show HP systems, and are composed of cat-ear-like sheets main structure and interconnected nanosheets secondary structure. Moreover, the secondary nanosheets are highly porous and consist of cross-linked nanoparticles of 30–100nm. The electrochemical performances of the HP-NiO sheets arrays are evaluated as anode for Li ion batteries. Compared with the normal NiO sheets arrays, enhanced electrochemical performances are achieved for the HP-NiO sheets, including higher capacity, better cycling life and high-rate capability. The HP-NiO sheets can deliver a specific capacity of 511mAhg−1 at 3Ag−1, higher than the normal NiO sheets arrays (374mAhg−1 at 3Ag−1), due to the hierarchical porous array configuration with large surface area, fast ion diffusion path and better accommodation of volume change.

Biotemplate assisted synthesis of 3D hierarchical porous NiO for supercapatior application with excellent rate performance

A novel 3D hierarchical porous nickel oxide (NiO) was fabricated by a facile biotemplate assisted method. Physicochemical characterizations indicate that the as prepared hierarchical porous NiO is assembled by multiple-layered porous nanosheets, of which the pore structure is highly ordered. The electrochemical performance of the as prepared hierarchical porous NiO was carried out in 6M KOH, exhibited relatively high specific capacitance value of 493Fg−1 at a current density of 0.3Ag−1, good rate performance (~93% capacity retention from 0.3Ag−1 to 10Ag−1), as well as good cycling stability (~96% retention upon 2000 charge/discharge cycles at 10Ag−1).

Hierarchical porous nickel oxide–carbon nanotubes as advanced pseudocapacitor materials for supercapacitors

Hierarchical porous carbon anode and metal oxide cathode are promising for supercapacitor with both high energy density and high power density. This Letter uses NiO and commercial carbon nanotubes (CNTs) as electrode materials for electrochemical capacitors with high energy storage capacities. Experimental results show that the specific capacitance of the electrode materials for 10%, 30% and 50% CNTs are 279, 242 and 112F/g, respectively in an aqueous 1M KOH electrolyte at a charge rate of 0.56A/g. The maximum specific capacitance is 328F/g at a charge rate of 0.33A/g.

High-performance supercapacitor and lithium-ion battery based on 3D hierarchical NH4F-induced nickel cobaltate nanosheet–nanowire cluster arrays as self-supported electrodes

A facile hydrothermal method is developed for large-scale production of three-dimensional (3D) hierarchical porous nickel cobaltate nanowire cluster arrays derived from nanosheet arrays with robust adhesion on Ni foam. Based on the morphology evolution upon reaction time, a possible formation process is proposed. The role of NH4F in formation of the structure has also been investigated based on different NH4F amounts. This unique structure significantly enhances the electroactive surface areas of the NiCo2O4 arrays, leading to better interfacial/chemical distributions at the nanoscale, fast ion and electron transfer and good strain accommodation. Thus, when it is used for supercapacitor testing, a specific capacitance of 1069 F g(-1) at a very high current density of 100 A g(-1) was obtained. Even after more than 10,000 cycles at various large current densities, a capacitance of 2000 F g(-1) at 10 A g(-1) with 93.8% retention can be achieved. It also exhibits a high-power density (26.1 kW kg(-1)) at a discharge current density of 80 A g(-1). When used as an anode material for lithium-ion batteries (LIBs), it presents a high reversible capacity of 976 mA h g(-1) at a rate of 200 mA g(-1) with good cycling stability and rate capability. This array material is rarely used as an anode material. Our results show that this unique 3D hierarchical porous nickel cobaltite is promising for electrochemical energy applications.

Hierarchical porous NiCo2O4 nanomaterials with excellent cycling behavior for electrochemical capacitors via a hard-templating route

Hierarchical porous nickel cobaltite (NiCo2O4) nanomaterials were synthesized via a hard-templating route. The obtained materials consist of nanostructured cubic NiCo2O4 spinels and a spot of cubic NiO nanoparticles, and the materials display a typical hierarchical porous structure. The NiCo2O4 electrode displays quasireversible dynamics characteristics, mainly Faradaic capacitance behavior and capacitance relaxation feature. The NiCo2O4 electrode exhibits an excellent long cycling behavior with no capacitance decays during 5,000 cycles at a current density of 2 A g−1 in 1 M KOH electrolytes, and the NiCo2O4 electrode exhibits both high power and energy performances even after 5,000 cycles with respective value of 1,758 W kg−1 and 8.3 W h kg−1 in 1 M KOH electrolytes, indicating that the NiCo2O4 nanomaterials are promising candidates for electrochemical capacitors.

Hierarchical porous nickel oxide and carbon as electrode materials for asymmetric supercapacitor

Asymmetric supercapacitor is constructed using hierarchical porous electrode materials of nickel oxide and carbon with the aim to facilitate ion transport. Hierarchical porous nickel oxide and carbon are prepared by template-directed synthesis. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charging–discharging are used to test the asymmetric supercapacitor and investigate the electrode processes at different supercapacitor voltages. The capacitance, energy density and power density of the asymmetric supercapacitor can be improved by elevating the supercapacitor voltage, and its cycling stability decays at high voltage, but the columbic efficiency stays close to 100%.