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The brucite structure and turbostratic structure of nickel hydroxide showing intercalation with H2O molecules.
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A significant amount of work on electrochemical energy storage focuses mainly on current lithium-ion systems with the key markets being portable and transportation applications. There is a great demand for storing higher capacity (mAh/g) and energy density (Wh/kg) of the electrode material for electronic and vehicle applications. However, for stati...
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... Rapid global economic progress based on excessive use of conventional and polluting fuels such as coal, oil, and natural gas, has become a major cause of climate change and pollution at increasingly dangerous levels. In this context, researchers have begun actively working on utilising clean energy sources, such as wind, solar, and other renewable sources, to address the pressures of growing energy demand in recent years [1][2][3]. Renewable energy sources are totally dependent on environmental conditions, however, which are frequently fluctuating and highly unstable. As a result, the adoption of energy storage devices is unavoidable to enable power fluctuation reduction and power quality improvement [4] [5]. ...
... However, several key limitations affect the specific capacitance of MnO2 SCs, including crystal type, morphology, conductivity, and the slow rate of ion transport [21]. MnO2 has four main crystal polymorphs: α-MnO2, β-MnO2, γ-MnO2, and δ-MnO2 (Fig. 2, Re-plotted from [2]). ...
... Nickel hydroxides have polymorphs that involve both β-NiOOH and γ-NiOOH, which are formed by the oxidation of β-Ni(OH)2 and α-Ni(OH)2. Notably, β-Ni(OH)2 is more widely used in SCs due to its higher chemical and thermal stability than other forms [2]. The phase transformation for nickel electrodes during charging and discharge cycles is illustrated in Fig. 3, (Re-plotted from [2]). ...
Transition metal oxides (TMOs) have received significant attention because of their higher specific capacitance, which has already been used to enhance the electrical conductivity and electrochemical performance of SCs. This work thus focuses on a review of the use of ruthenium oxide (RuO2), manganese oxide (MnO2), iridium (IV) oxide (IrO2), cobalt oxide (Co3O4), and nickel oxide (NiO), which are among the most widely used TMOs, in capacitor electrodes. Various preparation methods for TMOs are presented, and some of their disadvantages, including low electrical conductivity and weak cycle stability, are discussed alongside a review of the electrochemical properties of some mixed TMOs and their composites with various highly conductive carbon nanomaterials.
... On the other hand, nickel hydroxide has been extensively studied in various energy storage systems, such as Ni-Fe and Ni-Cd, or in supercapacitors [8,9]. However, in metal-air batteries, its electrochemical activity has rarely been studied, and it has only been used as a dopant to improve the conductive properties of other materials or as a component of the current collector in different systems [10,11]. ...
This study presents a cost-effective method for producing high-performance cathodes for aluminum-air batteries. Commercial fuel cell cathodes are modified through electrodeposition of nickel and manganese species. The optimal conditions for electrodeposition are determined using a combination of structural (Raman, SEM, TEM) and electrochemical (LSV, EI, discharge curves) characterization techniques. The structural analysis confirms successful incorporation of nickel and manganese species onto the cathode surface. Electrochemical tests demonstrate enhanced electrochemical activity compared to unmodified cathodes. By combining the favorable properties of electrodeposited manganese species with nickel species, a high-performance cathode is obtained. The developed cathode exhibits capacities of 50 mA h cm−2 in aluminum-air batteries across a wide range of current densities. The electrodeposition method proves effective in improving electrochemical performance. A key advantage of this method is its simplicity and cost-effectiveness. The use of commercially available materials and well-established electrodeposition techniques allows for easy scalability and commercialization. This makes it a viable option for large-scale production of high-performance cathodes for the next-generation energy storage devices.
... For fast and efficient catalyst reactivation a pH > 12 is required. The hydrogen evolution reaction occurs at a potential of − 0.83 V vs SHE [13,26], (Eq. 6). ...
... The induced photo-voltage provides enough energy for the redox reactions to occur. In the case of the hydrogen evolution reaction the overall potential that would be necessary for these reactions to occur (based on their standard potentials) is 1.32 V [26]. The overall potential between the AgCl cathode and the NiOOH/hematite anode would be reduced to 0.34 V. ...
... During electrodeposition of CoOOH and Ni(OH) 2 , both films crystalize in a layered structure intercalated with water molecules, i. e., in an α phase, [27,28] and both electrodes undergo a one-electron transfer proton insertion/expulsion reaction. Furthermore, Co and Ni atoms are located just next to each other in the periodic table. ...
The transition to Ni‐based battery cathodes enhances the energy density and reduces the cost of batteries. However, this comes at the expense of losing energy efficiency which could be a consequence of charge–discharge hysteresis. Here, a thermodynamic model is developed to understand the extent and origin of charge–discharge hysteresis in battery cathodes based on their cyclic voltammograms (CVs). This was possible by defining a Gibbs energy function that weights random ion insertion/expulsion, i. e., a solid solution pathway, against selective ion insertion/expulsion, i. e., a phase separation route. The model was verified experimentally by the CVs of CoOOH and Ni(OH)2 as solid‐solution and phase‐separating cathodes, respectively. Finally, a microscopic view reveals that phase separation and hysteresis are a consequence of large ionic radii difference of the reduced and oxidized central metal atoms. Phase separation in Ni batteries: This scheme shows that for a point between reduced and oxidized species, there are two possible states with two different energies depending on their history, i. e., hysteresis. We developed a thermodynamic model for battery cathodes that reveals this hysteresis as a consequence of phase separation.
... Hydroxides and oxide of nickel-metal have been used by researchers since the first half of the twentieth century for batteries applications, however with recent advances in nanotechnology the usage is no longer limited to batteries, but has found diverse applications in various advanced technologies such as electrocatalysis, 20,21 photocatalysis, 22,23 electrochromic devices, 24 electrochemical sensors, 25 batteries 26 and supercapacitors. 27 A supercapacitor or electrochemical capacitor is an energy storage device that stores electric charges between electrode-electrolyte interfaces. ...
In this study, a simple one-step approach has been proposed to treat a spent electroless nickel plating bath by precipitating nickel metal as nickel hydroxide. Beta phase nickel hydroxide β-Ni(OH)2 generated after the treatment of an electroless nickel plating bath was characterized by material characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of β-Ni(OH)2 was evaluated using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques. A specific capacitance of 332 F g⁻¹@5 mV s⁻¹ is obtained from the CV data with an energy density of 11.5 W h kg⁻¹ and power density of 207.5 W kg⁻¹. The GCD results show a specific capacitance of 330 F g⁻¹, which is in close agreement with the value obtained from the CV data. This work represents a scalable approach for the synthesis of β-Ni(OH)2 from plating waste and converting it into a value-added product. The β-Ni(OH)2 powder obtained from plating waste has comparable electrochemical properties to that of pristine β-Ni(OH)2 and other transition metal hydroxides produced by other chemical methods.
... The influence of the morphology, surface area and surface modification of carbonaceous additives on the performance of corresponding cathodes was evaluated for a lithium-sulfur battery [5]. Finally, two Ni(OH) 2 synthesis routes were discussed and their differences in mechanisms were presented for battery applications [6]. ...
Nanomaterials and nanotechnology have played central roles in the realization of high-efficiency and next-generation energy storage devices [...]
... Ni(OH) 2 was found to be the catalytic nanomaterial for the synthesis of CNTs at a low temperature of 450 • C via the CVD method, as was reported by Zeng's group [10]. Ni(OH) 2 can be easily fabricated via the hydrothermal method, the solvothermal method, and electrochemical treatment [11][12][13][14]. In regards to large-scale production for industrial fabrication, electrochemical treatments are currently widely used in this field. ...
In this paper, a facile and rapid aqueous-based electrochemical technique was used for the phase conversion of Ni into Ni(OH)2 thin film. The Ni(OH)2 thin film was directly converted and coated onto the network surface of Ni foam (NF) via the self-hydroxylation process under alkaline conditions using a simple cyclic voltammetry (CV) strategy. The as-formed and coated Ni(OH)2 thin film on the NF was used as the catalyst layer for the direct growth of carbon nanotubes (CNTs). The self-converted Ni(OH)2 thin film is a good catalytic layer for the growth of CNTs due to the fact that the OH− of the Ni(OH)2 can be reduced to H2O to promote the growth of CNTs during the CVD process, and therefore enabling the dense and uniform CNTs growth on the NF substrate. This binder-free CNTs/NF electrode displayed outstanding behavior as an electric double-layer capacitor (EDLC) due to the large surface area of the CNTs, showing excellent specific capacitance values of 737.4 mF cm−2 in the three-electrode configuration and 319.1 mF cm−2 in the two-electrode configuration, at the current density of 1 mA cm−2 in a 6 M KOH electrolyte. The CNTs/NF electrode also displayed good cycling stability, with a capacitance retention of 96.41% after 10,000 cycles, and this the excellent cycling performance can be attributed to the stable structure of the direct growth of CNTs with a strong attachment to the NF current collector, ensuring a good mechanical and electrical connection between the NF collector and the CNTs.
... devices, e.g., supercapacitors, batteries, sensors, as well as water electrolyzers. 10,[26][27][28][29][30] Nanoporous Ni(OH) 2 exhibits good electrocatalytic performance toward OER owing to its high surface area created by a large number of nanopores in this material and its intrinsic catalytic activity. Further, it is reasonable to develop more effective OER electrocatalysts based on Ni(OH) 2 , and since NiFe double hydroxides were found to possess superior electrocatalytic activity toward OER 15,[31][32][33] it was reasonable to incorporate Fe(OH) 3 into nanoporous Ni(OH) 2 . ...
We demonstrate a straightforward method for the synthesis of the high-performance double-hydroxide (Fe(OH)3‖Ni(OH)2) nanoporous composite electrocatalyst for oxygen evolution reaction (OER). A nanoporous Ni(OH)2 film was electrochemically deposited using water electrolysis, in which hydrogen bubbles acted as a dynamic template, and the generated hydroxide ions caused precipitation of Ni2+ ions from the solution. The capillary action of nanopores was used to introduce Fe3+ ions that were precipitated in the nanopores by dipping into a KOH solution. A series of characterization methods and electrochemical techniques were used to characterize the physicochemical properties and electrocatalytic behavior of the prepared catalyst toward OER. Experimental results suggest that the incorporation of Fe(OH)3 into the nanoporous Ni(OH)2 film to a level of ~4%mol can significantly enhance its electrocatalytic activity toward OER. The OER current density observed for as-synthesized Fe(OH)3‖Ni(OH)2 was higher by a factor of 3.9 compared to the original nanoporous Ni(OH)2. The enhanced performance resulted from the interfacial synergistic effects between the two hydroxides, likely due to the improved electronic structure and increased density of oxygen vacancies. Our synthetic method is quite simple, cost-effective, and holds great potential for practical application in water electrolysis.
... By increasing E, C À2 goes to zero as the applied potential increases, indicating the presence of a capacitance at the electrodeelectrolyte interface. Such behavior is typical of a p-type semiconductor, as NiO is [55,56]. The intercept with x-axis (E FB ) represents the so-called flat band potential [49e54,57e59]. ...
Electrochemical water splitting represents a promising alternative to conventional carbon-based energy sources. The hydrogen evolution reaction (HER) is a key process, still if conducted in alkaline media, its kinetics is slow thus requiring high amount of Pt based catalysts. Extensive research has been focused on reducing Pt utilization by pursuing careful electrode investigation. Here, a low-cost chemical methodology is reported to obtain large amount of microflowers made of interconnected NiO nanowalls (20 nm thick) wisely decorated with ultralow amounts of Pt nanoparticles. These decorated microflowers, dispersed onto graphene paper by drop casting, build a high performance HER electrode exhibiting an overpotential of only 66 mV at current density of 10 mA cm⁻² under alkaline conditions. Intrinsic activity of catalyst was evaluated by measuring the Tafel plot (as low as 82 mV/dec) and turnover frequencies (2.07 s⁻¹ for a Pt loading of 11.2 μg cm⁻²). The effect of Pt decoration has been modelled through energy band bending supported by electrochemical analyses. A full cell for alkaline electrochemical water splitting has been built, composed of Pt decorated NiO microflowers as cathode and bare NiO microflowers as anode, showing a low potential of 1.57 V to afford a current density of 10 mA cm⁻² and a good long-term stability. The reported results pave the way towards an extensive utilization of Ni based nanostructures with ultralow Pt content for efficient electrochemical water splitting.
... We now use the MDF to understand scale formation of nickel (hydr-)oxides thin films. Generally, Ni(OH) 2(s) initially grows at the surface and then NiO (s) evolves beneath it at moderate pHs and potentials (approximately 7 ≤ pH ≤ 15, -0.5 V ≤ V SHE ≤ 1 V) (Figure 2a) [5,26,27]. Primary surface NiO (s) initiates at lower pHs between 5 and 7. Huang et al. characterized this pH-dependent and depth-dependent nickel scale formation by reporting film identity and thickness at pH = 4.9 and 12.0 for distinct potentials in the range of -600 mV ≤ V SHE ≤ 800 mV [5]. Figure 2b shows their experimental Ni thin film depths, ∆h Ni (s) , at pH = 12 decrease nearly 2 nm with increasing oxidation potential from about -0.6 V to 0.8 V. Simultaneously, the subsurface NiO (s) film depth increases in magnitude from only 0.8 nm to 2.4 nm. ...
We formulate the maximum driving force (MDF) parameter as a descriptor to capture the thermodynamic stability of aqueous surface scale creation over a range of environmental conditions. We use formation free energies, $\Delta_f G$s, sourced from high-throughput density functional theory (DFT) calculations and experimental databases to compute the maximum driving force for a wide variety of materials, including simple oxides, intermetallics, and alloys of varying compositions. We show how to use the MDF to describe trends in aqueous corrosion of nickel thin films determined from experimental linear-sweep-voltometry data. We also show how to account for subsurface oxidation behavior using depth-dependent effective chemical potentials. We anticipate this approach will increase overall understanding of oxide formation on chemically complex multielement alloys, where competing oxide phases can form during transient aqueous corrosion.
