Nickel Oxide Electrode Research Articles

Enhancing energy storage with binder-free nickel oxide cathodes in flexible hybrid asymmetric solid-state supercapacitors

The need for flexible electrode materials for the development of flexible supercapacitors has drawn scientific interest recently. We present the successful synthesis of nickel oxide thin films using the successive ionic layer adsorption and reaction (SILAR) method, with the use of three different cationic precursors. This paper provides comprehensive details on the synthesized nickel oxide structure, morphology, and elemental analysis in addition to its electrochemical characteristics, which include specific capacitance (SCs), charge transfer resistance, etc. The produced nickel oxide electrodes achieved specific capacity as 120 C g−1, 517 C g−1, and 1147 C g−1 with different nickel precursors such as nickel chloride, nickel nitrate, and nickel sulfate respectively, at a 1 mA cm−2 current density. A flexible hybrid asymmetric solid-state supercapacitor (FHASS) (S:NiO//PVA-KOH//CuS) device delivered SCs of 165 Fg−1 at a 0.5 mA cm−2 current density, with a maximum SE of 58.87 Wh kg−1 at SP 347 W kg−1. FHASS device exhibits capacitive retention and coulombic efficiency of between 79 % and 96 % after 5000 successful GCD cycles. Also, the device retained an outstanding 97 % of its capacitance at a 175º bending angle. Furthermore, to illustrate its real-world applicability, the constructed device underwent 30 s of charging to a lightning LED table lamp for 90 s. The fabricated device is bringing a new era of broad integration of device-grade applications.

Understanding the Role of Corrosion and Reactive Oxygen Species in Electrochemical Ozone Production on Nickel and Antimony Doped Tin Oxide

Electrochemical ozone production (EOP), a six-electron reaction, offers promising green applications for water disinfection and organic synthesis. Nickel and antimony-doped tin oxide (Ni/Sb-SnO2, NATO) electrodes are known to be active for EOP. Still, the mechanism of NATO's selectivity and activity and the origin of its instability need to be clarified. We combine electrochemistry, spectroscopic detection of reactive oxygen species (ROS) using selective chemical probes, oxygen anion chemical ionization mass spectrometry (CIMS), and density-functional theory (DFT) simulations to identify the reaction mechanism and investigate the role of corrosion and homogenous reactive oxygen species in EOP on NATO electrodes. We identify hydrogen peroxide as a critical reaction intermediate. Our results suggest that the presence of nickel in NATO enables the catalysis of hydrogen peroxide to hydroperoxyl radicals, which subsequently undergo oxidation to produce ozone. The isotopic makeup of products shows that water is the primary source of ozone, but it also contains oxygen from the metal oxide lattice. The change in the isotopic generation pattern of ozone suggests that NATO catalysts corrode irreversibly, and the lattice oxygen is not regenerated, explaining NATO's instability.

Designing and simulating of NiO@Graphite asymmetric supercapacitor device using thermally optimized nickel oxide electrode

Designing and simulating of NiO@Graphite asymmetric supercapacitor device using thermally optimized nickel oxide electrode

Self-supported iron-doped nickel oxide multifunctional electrodes for highly efficient energy storage and overall water-splitting uses

Caused by complex synthesis processes, slow diffusion rates, and the formation of undesired nanostructures, it is tedious to produce a high-quality nickel oxide (NiO) electrodes for potential energy storage and water splitting applications. This paper introduces a novel chemical technique for producing self-supported iron-doped NiO electrodes having a high concentration of oxygen vacancies by utilizing different iron-based salts i.e. iron nitrate, iron chloride, iron ammonium sulfate, iron fumarate, and iron sulfate salts. After examining physical properties, the electrochemical energy storage and water splitting measurements were performed where iron nitrate precursor-mediated self-supporting Fe-NiO electrode confirms the optimum performance. Specifically, it exhibits a specific capacitance (SC) of 3302.5 Fg−1 at a current density of 5 Ag−1. The as-fabricated Fe-NiO-A//Bi2O3 asymmetric supercapacitor has a broad voltage range of 1.5 V, a remarkable volumetric-energy-density of 98.2 W hkg−1 at a power density of 900 Wkg−1, and a long-lasting cycling life with 92.6 % capacity retention after 5000 cycles at a current density of 15 Ag−1. A bifunctional Fe-NiO//Fe-NiO electrocatalyst demonstrates a current density of 10 mA cm−2 and remarkable long-term durability of 75 h without any degradation while operating at an ultra-low cell voltage of only 1.51 V, specifying importance of self-supported Fe-doped NiO electrodes for electrochemical energy storage and water splitting applications.

Nickel oxide electroplating and electrode surface modification for electrochemical detection of glutamate

The electrochemical behavior and catalytic properties of nickel oxide (NiOx) are enhanced through cathodic electroplating and subsequent electrochemical activation in an alkaline aqueous electrolyte. The electrochemical detection of ʟ-glutamate becomes feasible by introducing an amine group through immobilizing APTES ((3-aminopropyl)triethoxysilane) on the NiOx surface, resulting in a positive charge. The synergistic effect of electrochemically activated electroplated NiOx and the APTES-modified surface facilitates the effective electrochemical detection of trace ʟ-glutamate. The APTES-activated NiOx electrode exhibits a linear detection range of 0.2 nM to 2 mM for glutamate. This relatively wide concentration range is promising for the analysis of human biological fluids.

Exploration of facile hydrothermally produced pure nickel oxide nanostructures as an effective electrode material for the enhanced supercapacitor applications

Abstract This research work concerns with the magnetic and electrochemical characteristics of hydrothermally prepared nickel oxide (NiO) nanoparticles for their use as working electrode material in supercapacitor. Through the use of thermal gravimetric (TG-DTA), the thermal stability and heat adsorption/desorption characteristics of the as-produced NiO nanoparticles were examined. By using X-ray diffraction (XRD) technique at ambient, 600 °C and 800 °C annealing temperatures, the trigonal and cubic structure of the as prepared and annealed nanoparticles was discovered. The spherical and cubic morphology of the as synthesized and annealed (800 °C) NiO nanoparticles was confirmed through field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDAX) analysis. The functional groups, optical bandgap energy, surface chemistry, specific surface area and superparamagnetic behavior of the annealed (800 °C) NiO nanoparticles were determined through Fourier transform infra-red (FT-IR), UV-DRS, XPS, BET and VSM characterization approaches, respectively. At the lowest scan rates of 10 mVs−1 and 0.5 Ag−1, the pseudocapacitive behavior was noticed utilizing CV and GCD analyses. An excellent electrical conductivity for the supercapacitor application was also shown by the Nyquist plot of the produced NiO electrode.

Spray pyrolyzed thorn-like nanostructured nickel oxide electrodes for symmetric supercapacitor device

Spray pyrolyzed thorn-like nanostructured nickel oxide electrodes for symmetric supercapacitor device

Utilization of spray pyrolyzed porous nickel cobaltite electrode as an advanced material for NiCo2O4@Graphite asymmetric supercapacitor device

Nickel-based probe ingredients are vastly promoted in energy storage devices due to their simply variable structure, greater electrochemical movement and nominal noisomeness. In the existing manuscript, we did a comparative study of spray pyrolyzed nickel oxide and nickel cobaltite thin film electrodes and their asymmetric supercapacitor devices for supercapacitor applications. In a three-electrodes arrangement, pristine nickel oxide shows a maximum specific capacitance of 397.10 Fg−1 at 0.002 V scan rate with 86.40 % retention after 5000 cycles. The same electrode shows the values of energy density and power density 45.16 Whkg−1 and 05 Wkg−1 respectively. Nickel cobaltite (NiCo2O4) electrode exhibits the highest value of specific capacitance is 676.82 Fg−1 with 89.23 % retention after 5000 cycles and the values of energy and power densities are 1123.41 Whkg−1 and 5.76 Wkg−1 respectively. The fabricated NiCo2O4@graphite asymmetric device shows a specific capacitance (according to CV analysis) of 495.10 Fg−1. According to the GCD analysis, the NiCo2O4@Graphite device exhibits a specific capacitance of 675.72 Fg−1 and the energy and power densities are 3249.6 Whkg−1 and 10 Wkg−1 respectively. The outcomes show that nickel–cobalt oxide materials play an important role in the field of energy storage.

Development of Nanoporous Nickel Oxide Materials as Electrodes for Supercapacitors

As a potential electrochemical energy storage device, supercapacitor has been researched owing to its low weight, excellent power density, outstanding charging rate, and long durability. For the supercapacitor, the electrode material and its morphology determine its overall performance. Nickel oxide (NiO) is a promising material for the electrode because of its low cost, high specific capacitance, and eco-friendly manufacturing process. In this research, we developed a simple and cost-effective method to fabricate supercapacitor electrodes by electrospinning and thermal annealing, making porous nickel oxide nanofibers directly grow on 3D-nickel foam. The binder-free design and porous structure of electrodes enhance the ion transport and electron transfer in the supercapacitor. The crystal structure of NiO was identified by X-ray diffractometry (XRD). The morphological and microstructural characterization was analyzed by scanning electron microscopy (SEM). The electrochemical test was carried out in a three-electrode electrochemical cell with the obtained foamed NiO as the working electrode, the platinum sheet as the counter electrode, and the Ag/Cl electrode as the reference electrode. The electrochemical performance was evaluated by using cyclic voltammetry (CV), galvanostatic charge/discharge technique, and electrochemical impedance spectroscopy (EIS). Due to the large specific surface area and good electrical conductivity of the NiO electrode, the supercapacitor exhibited excellent electrochemical performance (591 F/g at 2 A/g). After 1500 cycles of charging and discharging at 10 A/g, the capacitance of the supercapacitor using the NiO electrode increased by 21.7% with excellent cycle stability.

Germanium‐Functionalized 3D Microporous, Nanostructured Nickel–Nickel Oxides for Application in Asymmetric Supercapacitors

Supercapacitors and batteries are essential for sustainable energy development. However, the bottleneck is the associated high cost, which limits bulk use of batteries and supercapacitors. In this context, realizing that the cost of energy‐storage device mainly depends on materials, synthesis processes/procedures, and device fabrication, an effort is made to rationally design and develop novel low‐cost electrode materials with enhanced electrochemical performance in asymmetric supercapacitors. Herein, surface functionalization approach is adopted to design low‐cost 3D mesoporous and nanostructured nickel–nickel oxide electrode materials using facile synthesis for application in supercapacitors. It is demonstrated that the 3D mesoporous Ni provides the high surface area and enhanced ionic conductivity, while germanium functionalization improves the electrical conductivity and reduces the charge‐transfer resistance of NiO. Surface functionalization with Ge demonstrates the significant improvement in specific capacitance of NiO. The asymmetric supercapacitor using these Ge‐functionalized NiO–Ni electrodes provides a specific capacitance of 304 Fg−1 (94 mF cm−2), energy density of 23.8 Wh kg−1 (7.35 μWh cm−2), and power density of 6.8 kW kg−1 (2.1 mW cm−2) with excellent cyclic stability of 92% after 10 000 cycles. To validate their practical applications, powering the digital watch using the asymmetric supercapacitors in laboratory conditions is demonstrated.

Amorphous nickel oxide electrodes with high-current-density electrocatalytic performance for hydrogen evolution

The widespread use of unsustainable fossil fuels has caused serious damage to the ecological environment. The development of sustainable clean energy is urgent. Producing hydrogen by water electrolysis can effectively solve fossil energy shortage and environmental pollution issues. The preparation of inexpensive, efficient, and stable electrocatalytic hydrogen evolution electrode materials is the key to achieving the application of electrocatalytic hydrogen evolution. Herein, the amorphous nickel oxide/nickel foam (NiOx/NF) hydrogen evolution electrode was prepared by a simple one-step hydrothermal method with hydrogen peroxide as an oxidant. The amorphous leaf array structure of NiOx/NF electrode can enrich the surface composition and expose more catalytic active sites. Further, hydrogen peroxide etching can optimize the electronic structure of NiOx, and accelerate the electron migration. Thus, NiOx/NF displays excellent alkaline hydrogen evolution activity with the low over potentials of 70, 318 and 361 mV at 10, 500 and 1000 mA cm−2, respectively, leading to high performance in alkaline HER than those of reported Ni-based electrodes and even surpasses commercial Pt/C at high current density. Our work provides a new approach for developing inexpensive electrocatalysts with excellent alkaline hydrogen evolution activity and stability.

Standalone nickel layered double hydroxide and nickel oxide electrodes as effective anodes in alkaline direct methanol fuel cell

Direct methanol fuel cell is an emerging energy transformation system with the prospect of substituting secondary batteries soon due to their exciting features. One of the most limitations is the weak catalytic activity of the expensive nonprecious Pt-based catalysts at the fuel cell's anode. In this work, a standalone Nickel layered double hydroxide of hierarchical nanosheet structure was effectively synthesized on the nickel foam's surface through facile hydrothermal treatment that subsequently converted into NiO without destroying the structure by heat treatment at 500 °C. The synthesized standalone electrodes demonstrated a significant activity for methanol oxidation with an onset potential of 0.35 V in KOH (1 M), which is attributed to the Ni(OH)2 (Ni+2)/(Ni+3) NiOOH active site. The electrodes effectively discharged current at 0.5 V for more than 1 h with no performance degradation compared to the bare nickel foam. The better activity of the synthesized electrodes was attributed to the nanosheet structure layer's better charge and mass transfers, as confirmed by the morphological images (SEM images) and the electrochemical characteristics (electrochemical impedance spectroscopy, chronoamperometry, and cyclic voltammetry).

Spray pyrolyzed hydrophilic nickel oxide electrodes with nano-granular morphology for a symmetric supercapacitor device

The symmetric supercapacitor device is efficiently invented using two identical sprayed nickel oxide thin film electrodes equipped via an aqueous path. Firstly, we did a comparative study of structural, morphological and electrochemical characterizations of nickel oxide electrodes which are prepared by varying concentrations of the precursors (0.2, 0.4, 0.6, 0.8 and 1.0 M and renamed according to their concentration as AC (Aqueous Concentration) AC-1, AC-2, AC-3, AC-4 and AC-5 respectively). XRD patterns of all electrodes confirm cubic crystal structure. The highest value of specific capacitance of NiO@AC-4 (0.8 M) electrode is 256.32 Fg−1 at 0.002 Vs−1 which is the maximum among all electrodes. The specific energy and specific power of the AC-4 electrode at 0.002 Acm−1 are 29.08 Whkg−1 and 3.06 kWkg−1 respectively. NiO@AC-4 electrode shows 69.42% retention in capacitance value after 5000 cyclic voltammetric cycles. The fabricated device parades specific capacitance (SC) 92.81 Fg−1 at 0.002 Vs−1. The wettability study depicts the hydrophilic nature of all electrodes (except the NiO@AC-1 electrode). As concentration increases morphology of the prepared electrodes changes from impenetrable to porous micro globules. SEAD pattern rings and XPS investigation are well matched with XRD analysis.

Construction of highly transparent, flexible, and robust solid-state symmetric supercapacitors using NiO electrodes roughened by conformal atomic layer deposition

Transparent flexible supercapacitors (TFSCs) have received significant attention as a power source for modern high-tech wearable electronic gadgets. Although carbon nanomaterials have been employed to manufacture TFSCs, unsatisfactory electrochemical performance and poor optical transparency have restricted their commercial use. In the present study, a TFSC device with large areal capacitance, excellent cyclic stability, and high optical transparency was developed by enhancing the electronic conductivity of the pseudocapacitive material using atomic layer deposition (ALD). In this method, a conformal nickel oxide (NiO) layer whose roughness was readjusted according to its thickness was successfully fabricated on a flexible substrate. The NiO film exhibited a high areal capacitance of 1.51 mF cm−2 at an optical transparency of > 81 % when employed as a TFSC electrode, and it outperformed other state-of-the-art TFSC electrodes. The symmetric solid-state TFSC fabricated via the complete integration of these layers exhibited scalable areal capacitance and cyclic stability at a transmittance of 76 %. These findings demonstrate the potential of ALD-based NiO electrodes for use in sustainable and integrated supercapacitor applications.

A facile electrochemical lithiation method to prepare porous nickel oxide electrodes with high electrochromic performance

A facile electrochemical lithiation method was developed in the framework of the wet chemical route, and NiO films with various lithium contents have been successfully prepared. The structure and electrochromic properties were characterized using SEM, HRTEM, XRD, XPS, etc. The results indicate that all NiO films show a porous morphology, and the ratio of Ni3+/Ni2+ increases from 1.12 to 1.46 after electrochemical lithiation. The storage capacity in lithium electrolytes, effective ionic diffusion rate, transmittance modulation, and coloring efficiency are effectively improved. The optimized NiO electrode exhibits an excellent storage capacity of 6.4 mC/cm2 and transmittance modulation at 550 nm of 35.7%, compared to the pristine NiO (Q = 4.4 mC/cm2, ΔT = 24.3%). Two electrochromic devices were respectively assembled with the pristine and lithiated NiO electrodes as the anodic electrochromic layer. The latter exhibits higher transmittance modulation and coloring efficiency, proving that the electrochemical lithiation method is an effective way to prepare high-performance electrochromic devices.

Investigation of cycling effect on the enhancement of electrochemical activity of zinc doped nickel oxide

Supercapacitor activity can be greatly influenced by the doping, conductivity, and the morphology of the electrocatalyst surface. Here, we are reporting the synthesis and characterization of undoped and zinc doped nickel oxide nanoparticles for investigating the influence of doping and cyclability on the supercapacitor activity using cyclic voltammetry (CV) measurements. We found that the activity of zinc doped NiO initially increases as per increase in number of CV cycles up to the fifty cycles and beyond this it decreases further. It is interesting to note that the cyclic voltammetry changes the morphology of the electrocatalyst surface, which enhances its activity. The polarization study of the fresh and cycled electrode showed the increase of Ni +3 content for the cycled electrode is responsible for the enhanced activity. Further, the impedance and galvanostatic charge discharge analysis showed that the pseudocapacitance of the cycled zinc doped electrode is higher than that of cycled nickel oxide electrode. Phenomenologically, the presence of Ni +3 and the increased electronic conductivity due to presence of zinc, with cyclic voltammetry cycling changes the energy of the surface, which increases the supercapacitor activity.

Transparent, photosensitive and highly efficient pseudocapacitive binder-free Mo-modified NiO thin film electrode for bifunctional optoelectronic and energy storage applications

We report a novel highly sensitive and pseudocapacitive transparent nickel oxide (NiO) thin film based electrode material fabricated on a conductive glass substrate using a facile binderless electrodeposition process. Effect of the incorporation of Mo-dopant ion on some surface structural and electrochemical properties of the electrode was examined for high performance optoelectronic and charge storage potentials. The material showed some uniqueness in some microstructural features and enhanced degree of crystallinity, suitable for charge extraction and transport with Mo doping. The deposited NiO film demonstrated red shift in band structure by exhibiting optical band gap narrowing from 3.88 to 3.61 eV with increasing Mo content. The degree of disorder as revealed from Urbach response of NiO film was found varying with Mo-content. The material also exhibited enhanced Ni2+ electronic transition states with increasing Mo content which quenched at a critical dopant concentration of 2.4 %. The fabricated NiO thin film electrode showed increased supercapacitive specific capacitance and areal capacity up to a peak value of 1412 Fg−1 and 101 mAh m−2 for 3 % Mo dopant content at 5 mVs−1 scan rate and 0.5 mA cm−2, respectively, but returned diminished at higher dopant content. Excellent cycling stability at ∼ 85 % after 5000 cycles, was also exhibited. Impedance spectroscopic features of Mo-doped NiO electrode indicated fast electrolytic ion transfer response with high rate charge storage capability. The study presents successful fabrication of Mo-modified NiO nanostructured electrode film and demonstrated the influence of Mo impurity on tailoring the properties of NiO host film as suitable electrode in high performance photocatalytic and supercapacitor devices.

Medium-independent hydrogen atom binding isotherms of nickel oxide electrodes

<h2>Summary</h2> Adsorption and transfer of hydrogen atoms at solid/solution interfaces are fundamental to heterogeneous catalysis for chemical energy transformations and other processes. Reported here are electrochemical and spectroelectrochemical measurements of the thermodynamics of H-atom binding to nickel oxide electrodes, both the average and the distribution of NiO–H bond dissociation free energies (BDFEs). These are perhaps the first measurements of binding isotherms at non-metal electrodes. Remarkably, both the BDFEs and the non-Langmuirian isotherms are the same in water, acetonitrile, and dimethylformamide, and with different buffers and proton activities. Such medium independence of the BDFEs and isotherms has not been previously reported for any binary material. The medium independence supports the common use of computed hydrogen binding energies as intrinsic descriptors of surface reactivity, while the broadened isotherms add a level of complexity to such analyses. This work demonstrates the capability to derive key thermodynamic parameters at chemically reactive solid-liquid interfaces.

Nickel Oxide-Incorporated Polyaniline Nanocomposites as an Efficient Electrode Material for Supercapacitor Application

This work reports the facile, controlled, and low-cost synthesis of a nickel oxide and polyaniline (PANI) nanocomposites-based electrode material for supercapacitor application. PANI-NiO nanocomposites with varying concentrations of NiO were synthesized via in-situ chemical oxidative polymerization of aniline. The XRD and FTIR support the interaction of PANI with NiO and the successful formation of the PANI-NiO-x nanocomposite. The SEM analysis showed that the NiO and PANI were mixed homogenously, in which the NiO nanomaterial was incorporated in porous PANI globular nanostructures. The multiple phases of the nanocomposite electrode material enhance the overall performance of the energy-storage behavior of the supercapacitor that was tested in 1 M H2SO4 using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Among the different nanocomposites, PANI-NiO-3 exhibit the specific capacitance of a 623 F g−1 at 1 A g−1 current density. Furthermore, the PANI-NiO-3 electrode retained 89.4% of its initial capacitance after 5000 cycles of GCD at a 20 A g−1 current density, indicating its significant cyclic stability. Such results suggest that PANI-NiO nanocomposite could be proposed as an appropriate electrode material for supercapacitor applications.

Study on Ion Transport Mechanism of Zinc-Nickel Single-Flow Battery with Different Porous Electrode Structures based on Lattice Boltzmann Method

Since the microstructure of porous electrode is very important to the performance of zinc-nickel single-flow battery, this paper reconstructed the microstructure of porous nickel oxide electrode by quartet structure generation set (QSGS) method. The flow mass transfer and electrochemical reaction in porous electrode were simulated by lattice Boltzmann method (LBM). The effects of different porous electrode structures (porosity, particle size and electrode thickness) on local ion concentration distribution and charging performance are studied from the perspective of seepage and mass transfer in pores. It is found that the ion concentration in the electrode presents an uneven distribution due to the randomness of the particle size and distribution of active substances. The uneven distribution of OH − concentration caused the difference of charging depth in the direction of electrode thickness, and the uneven distribution of H + concentration caused the difference of charging depth in the radial direction of particles. Under different pore structures, the decrease of porosity and particle size can increase the diffusion rates of OH − and H +, and then promote the electrochemical reaction rate, improve the charging speed of the battery, and improve the performance of the battery. The larger electrode thickness will increase the OH − diffusion resistance in the electrode, which is not conducive to the diffusion of OH − and reduce the electrochemical reaction rate, thus affecting the diffusion of H +, increasing the concentration polarization and affecting the charging efficiency of the battery. The uneven distribution of OH − concentration caused the difference of charging depth in the direction of electrode thickness, while the uneven distribution of H + concentration caused the difference of charging depth in the radial direction of particles. Under different pore structures, the decrease of porosity and particle size can increase the diffusion rate of OH − and solid phase H +, and then promote the electrochemical reaction rate and accelerate the charging speed. The larger electrode thickness increases the OH − diffusion resistance in the electrode, which is not conducive to OH − diffusion, and then affects H + diffusion and increases concentration polarization.