Titanium Nitride Layer Research Articles

Nanostructures/TiN layer/Al2O3 layer/TiN substrate configuration-based high-performance refractory metasurface solar absorber

Metasurface solar absorber serves as a kind of important component for green energy devices to convert solar electromagnetic waves into thermal energy. In this work, we design a new solar light absorber configuration that incorporates the titanium nitride substrate, aluminum oxide layer, titanium nitride layer, and the topmost refractory nanostructures. The metasurface absorber based on this configuration can achieve an average spectral absorption of over 91% and a total solar radiation absorption of 91.5% at ultra-wide wavelengths of 300–2500 nm. It is discovered that the excellent performance of the proposed metasurface absorber is attributed to the synergistic effects of surface plasmonic effect and Fabry–Pérot (FP) cavity resonance by comprehensive analysis of the simulated field distributions. Furthermore, the effect of geometrical parameter of the proposed configuration on absorber performance is studied, indicating the proposed configuration possesses a large fabrication tolerance. Moreover, the proposed configuration is not sensitive to the polarization direction and the angle of incident light. It is also found that the use of other refractory metal materials and other shapes as the topmost absorbent nanostructures also have good results with this configuration. This work can offer a universal platform for constructing and guiding the design of refractory metasurface solar absorbers.

Structural state and physical-mechanical properties of multilayer vacuum arc Ti/TiN coating

Abstract. Problem. Increasing the resource of the cutting tools in conditions of variable load is of great importance, as it affects not only the cost of production but also the competitiveness of the enterprise. A wide range of properties of vacuum arc multilayer coatings allows them to be used in mechanical engineering to increase the performance of the tools in the variable conditions of cutting. Goal. The goal is to study the structural state and physical and mechanical properties of vacuum arc multilayer Ti/TiN coatings. To achieve the goal, it is necessary to analyze the effect of the thickness of the titanium layer and the amount of negative stress on the substrate on the structure, stress-strain state, and physical and mechanical properties of the multilayer Ti/TiN coating with relatively thick layers of titanium nitride. Methodology. Multilayer Ti/TiN coatings were obtained in the Bulat-6 vacuum-arc installation. The study of mechanical characteristics was carried out by the indentation method using the MicronGama microindenter. Structural studies of the samples were carried out on a DRON-3M diffractometer. Electron microscopic studies were performed on a JEOL JSM-840 scanning electron microscope. Originality. It was found that in titanium nitride layers with a thickness of 300 nm or more, a texture develops when a voltage is applied to the substrate. The degree of texture perfection increases with increasing layer thickness. When the thickness of the titanium layer is from 30 nm to 250 nm, the development of the stress-strain state in the titanium nitride layers takes place without significant relaxation. The mechanical properties of the Ti/TiN multilayer coating remain quite high (hardness 33.7...36.3 GPa with a modulus of elasticity 413...434 GPa) when the thickness of the titanium layer is less than 125 nm. Practical value. Increasing the crack resistance of Ti/TiN multilayer coatings due to the introduction of titanium layers makes their use promising for hard loads.

Enhancing geometric integrity and surface hardness of SLM-printed Ti-6Al-4V components with support structures and laser nitriding

This study investigated the effect of support structure and post-processing surface nitriding on high aspect ratio Ti-6Al-4V components fabricated using Selective Laser Melting (SLM). It examined changes in geometric integrity, porosity, and mechanical properties. Samples were printed without support structures (S1) and with support structures (S2). After SLM printing, both samples underwent open-air laser nitriding at duty cycles (DC) ranging from 50 % to 100 %, aiming to create crack-free nitride layers to increase surface hardness. The results indicated that support structures effectively mitigate thermal-induced deformation, with S2 exhibiting minimal warping and closer adherence to design specifications than S1. Although S2 showed increased porosity as revealed by X-ray Computed Tomography (XCT), its refined microstructure contributed to increased hardness. Optical Microscope and Scanning Electron Microscope (SEM) analyses demonstrated that laser nitriding at a 50 % duty cycle produced uniform, crack-free titanium nitride (TiN) layers. Vickers hardness tests revealed a significant enhancement in the surface hardness of both laser-nitrided samples, with S2 displaying finer TiN dendrites that further improved its surface hardness. The use of support structures was found to be effective in achieving a more uniform microstructure and enhanced hardness in the nitride layer.

Wrinkled TiNAgNW Nanocomposites for High-Performance Flexible Electrodes on TEMPO-Oxidized Nanocellulose.

In this study, we present a novel method for fabricating semi-transparent electrodes by combining silver nanowires (AgNW) with titanium nitride (TiN) layers, resulting in conductive nanocomposite coatings with exceptional electromechanical properties. These nanocomposites were deposited on cellulose nanopaper (CNP) using a plasma-enhanced pulsed laser deposition (PE-PLD) technique at low temperatures (below 200 °C). Repetitive bending tests demonstrate that incorporating AgNW into TiN coatings significantly enhances the microstructure, increasing the electrode's electromechanical robustness by up to four orders of magnitude compared to commercial PET/ITO substrates. Furthermore, the optical and electrical conductivities can be optimized by adjusting the AgNW network density and TiN synthesis temperature. Our results also indicate that the nanocomposite electrodes exhibit improved stability in air and superior adhesion compared to bare AgNW coatings.

Plasmon assisted synthesis of TiN-supported single-atom nickel catalysts

We report the deposition of single atom nickel catalyst on refractory plasmonic titanium nitride (TiN) nanomaterials supports using the wet synthesis method under visible light irradiation. TiN nanoparticles efficiently absorb visible light to generate photoexcited electrons and holes. Photoexcited electrons reduce nickel precursor to deposit Ni atoms on TiN nanoparticles’ surface. The generated hot holes are scavenged by the methanol. We studied the Ni deposition on TiN nanoparticles by varying light intensity, light exposure time, and metal precursor concentration. These studies confirmed the photodeposition method is driven by hot electrons and helped us to find optimum synthesis conditions for single atoms deposition. We characterized the nanocatalysts using high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). We used density functional theory (DFT) calculations to predict favorable deposition sites and aggregation energy of Ni atoms on TiN. Surface defect sites of TiN are most favorable for single nickel atoms depositions. Interestingly, the oxygen sites on native surface oxide layer of TiN also exhibit strong binding with the single Ni atoms. Plasmon enhanced synthesis method can facilitate photodeposition of single atom catalysts on a wide class of metallic supports with plasmonic properties.

First-principles study of F adsorption by TiN with its oxide surface in three-dimensional NAND flash memory

Three-dimensional (3D) NAND flash memory is a key technology in the field of mainstream memory solutions, which is primarily due to its extremely low bit cost. The architecture of 3D NAND, characterized by its vertically stacked design, substantially enhances the capacity of individual chips. This advancement is completely consistent with the demands for high-capacity data storage in contemporary environments, securing its widespread adoption in diverse application scenarios. As storage density increases, the complexity of process integration increases, bringing new challenges. The word lines in 3D NAND are typically filled by using gate replacement techniques, and compared with chemical vapor deposition (CVD), atomic layer deposition (ALD) is favored for its superior step-coverage, especially for depositing tungsten (W) at the gate. However, due to the complexity of the replacement gate deposition structure, fluorine (F) residues are found in the voids of the tungsten metal gate filling structure and diffuse into the surrounding structure under subsequent process conditions, corroding other films such as silicon oxide and degrading device performance and reliability. To alleviate the problem of fluorine attack, a thin layer of titanium nitride is usually deposited as a barrier layer before deposition of tungsten gate, which blocks the fluorine in the tungsten gate and prevents its diffusion into the oxide layer. Previously, there were studies to increase the ability to stop F diffusion by varying the thickness of the F blocking layer (TiN). However, increasing the thickness of TiN will further increase the complexity of high aspect ratio etching in the 3D NAND process, which will have adverse effect on subsequent processes. To further minimize the effect of fluorine erosion, residual fluorine elements can be removed by introducing annealing in the subsequent process flow. In the actual 3D NAND process, elemental fluorine (F) is adsorbed and accumulates on the TiN surface, and is further activated by subsequent high-temperature processes, leading to severe fluorine erosion. The delay between TiN deposition and subsequent processing steps is hypothesized to facilitate fluorine adsorption due to the oxidation of TiN. This work corroborates this hypothesis through first-principles calculations, and demonstrates the role of TiN oxidation in fluorine adsorption. In this work, we evaluate the effect of this oxidation on the fluorine-blocking effectiveness of the TiN barrier layer. We simulate the adsorption of fluorine-containing by-products on TiN and its oxides, providing theoretical insights into mitigating fluorine attack. The higher degree of oxidation of TiN is more likely to cause F adsorption, and Ti exposed surface TiN is more prone to oxidation, which is more likely to cause F adsorption in unoxidized condition and oxidized condition. Based on these insights, we implemente an ammonia purge treatment in 3D NAND manufacturing, which effectively minimizes fluorine attack, reducing the leakage probability of word line by 25% and wafer warpage by 43%.

Thin Sputtered Titanium Nitride Layers for Corrosion Protection of 316L Stainless Steel Under PEM Water Electrolyzer Anode-like Conditions

Proton exchange membrane water electrolyzers (PEMWE) electrochemically split the water molecule in order to produce high-purity oxygen (at the anode) and hydrogen (at the cathode). When coupled to a renewable energy source (such as wind or sun), green hydrogen can be synthesized, which may contribute to a massive reduction in carbon dioxide emissions in the so-called “hard-to-abate” industrial sectors, like steel and cement manufacturing.Yet, the elevated capital expenditures (capex) deriving from the use of expensive corrosion-resistant materials undermine the economic competitiveness of the PEMWE technology compared to the main hydrogen production processes, like steam reforming. To date, on the PEMWE anode side, metallic bipolar plates (BPP) and porous transport layers (PTL), are essentially made of titanium coated with precious metal layers (platinum, gold) so as to withstand the corrosive and oxidizing environment. Consequently, BPP and PTL account for more than 60% of the capex of the PEMWE stack [1,2]. Without corrosion protection, the harsh operating anodic conditions may lead to performance-killing release of cationic elements from the BPP and PTL into the catalyst layer and the polymer electrolyte [3]. It may also cause the growth of resistive oxide layers at the BPP and PTL surfaces and the development of undesired interfacial contact resistance (ICR).This contribution will focus on the corrosion protection of the anode side of BPP and will first briefly review the most recent investigations driven by capex reduction, notably based on the replacement of titanium by stainless steels and the application of novel, more cost-effective anti-corrosion coatings [3].In a second part, results on the corrosion protection of 316L stainless steel by thin layers of titanium nitride prepared by DC magnetron sputtering will be presented. The thin TiN coatings were deposited on glass, silicon and 316L stainless steel substrates using a titanium target reacting with nitrogen gas. The crystalline phase, the nanostructure and the composition of the thin films were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray reflectivity, energy dispersive X-ray spectroscopy and electron energy loss spectroscopy. The corrosion resistance of the TiN-coated stainless steel was evaluated ex situ using open-circuit potential monitoring and electrochemical impedance spectroscopy in dilute H2SO4 solution in a three-electrode electrochemical cell. The interfacial contact resistance was assessed before and after corrosion testing. The protective properties of titanium nitride coatings on 316L under PEMWE anode-like conditions will be discussed.Acknowledgements The authors gratefully acknowledge the financial support of the French National Research Agency (agreement ANR-22-PEHY-0009 under the France 2030 program as well as agreement ANR-22-CE93-0008-01).

High transparent conductive Ga-doped ZnO-based multilayer thin films with embedded ultrathin TiN layer deposited in oxygen-containing atmosphere.

To avoid metal layer oxidation during the deposition of transparent conductive oxide (TCO)/metal/TCO multilayer films in an oxygen-containing atmosphere, the ultra-thin (<10 nm) titanium nitride (TiN) layer has been proposed to replace metal embedding in gallium-doped zinc oxide (GZO) film for the development of indium-free transparent electrodes. The effects of TiN thickness on the structure, morphology, electrical, and optical properties of GZO/TiN/GZO multilayer thin films deposited in argon-oxygen mixtures on glass substrates by magnetron sputtering are investigated. The experimental results reveal that multilayers with the 8 nm-thick TiN layer have the optimal performance (figure of merit of 2.75 × 10-1 Ω-1): resistivity of 4.68 × 10-5 Ω cm, and optical transmittance of above 91% in the visible region, which is superior to the sandwich film with the metal embedded layer.

Numerical Study of Graphene‐Based Wideband Solar Absorber using MIM Structure for Solar Thermal Energy Conversion

AbstractA super‐wideband solar energy absorber (SWBSEA) design is proposed in this research. In order to achieve high absorption in the design, a thin film of graphene is also used as a substrate coating that is exposed to the medium of air. The metal‐insulator‐metal (MIM) is designed with a Ti‐SiO2‐TiN structure. The fractal interwoven shape (FIS) resonator layer is constructed of titanium material, which is based on a layer of silicon dioxide, and a ground layer of titanium nitride. The spectrum of solar radiation that is typically absorbed spans from the Ultraviolet (UV) to Mid‐infrared (MIR) range, with 92.81% average absorption. The absorption bandwidth of 0.61 µm is achieved with 96.21% average absorption. The designed solar absorber has a wide angle of incidence ranging from 0° to 80°. The design is also polarization insensitive for Transverse Electric (TE) and Transverse Magnetic (TM) waves. The created SWBSEA solar absorber design is extremely effective, polarization, and angle‐insensitive, and offers broadband absorptance that may be put into the solar cell as an absorber and is frequently utilized in heating, drying, and photovoltaic applications.

Microstructural and Electrical Resistivity of TiN Electrode Films Prepared by Direct Current (DC) Reactive Magnetron Sputtering

In this study, the crystal structure as well as electron transport of TiN thin films were evaluated. We used DC reactive magnetron sputtering to deposit a thin layer of polycrystalline titanium nitride (TiN) on a Si (100) substrate starting from elemental Ti in a nitrogen atmosphere. The influence of nitrogen flow rate on the crystal structure, surface morphology, and electron transport of TiN were investigated systematically. It was found that the preferred orientation and conductivity of TiN thin films exhibit strong nitrogen flow rate dependence. The preferred orientation changed from (111) to (200) initially and then changed back to (111) as the nitrogen flow rate increases. However, an increase in the (200) phase leads to higher conductivity and lower surface roughness. At the optimized deposition conditions, ultra-thin (around 30 nm) TiN thin films with a low resistivity of 101.8 μC·cm and a surface roughness of less than or equal to 0.51 nm were obtained. These superior performances, along with low running costs, suggest that TiN thin films have great potential for use as electrodes in microelectronic devices.

Morphology tuned plasmonic TiN nanostructures formed by angle-dependent sputtering process for SERS measurements

Nowadays, most SERS platforms are based on plasmonic metals like silver and gold. The current scientific achievement is to construct SERS non-metallic platform with SERS activity not worse than in case of standard metallic platforms. The prominent combination of opto-electronic properties of TiN (titanium nitride) makes it a promising alternative plasmonic material for noble metals. So far, the TiN nanostructures are widely tested in catalysis, especially in photocatalysis. Despite the TiN potential in SERS sensing applications, there are still several fundamental issues preventing its wide practical application. In this work, the surface morphology of TiN layers was tuned from planar 2D to a high aspect ratio 1D nanorod-like structures by industrially scalable normal and glancing angle deposition (GLAD) pulsed DC reactive sputtering. The morphology of formed samples was studied by SEM microscopy, while the crystallographic properties were examined by Raman and XRD method. The opto-electrical parameters measured by spectroscopic ellipsometry, and DRS spectroscopy revealed substantial changes in optical properties of the TiN films with the variation of glancing angle. This in turn opened the way for tailoring the surface plasmon resonance and hence for SERS activity.

Enhancing poly-Si contact through a highly conductive and ultra-thin TiN layer for high-efficiency passivating contact silicon solar cells

High-performance passivating contacts with excellent electron selective property is a prerequisite for silicon solar cells with high power conversion efficiency. In this work, a highly conductive, ultra-thin electron-selective titanium nitride (TiN) film is prepared by reactive magnetron sputtering for tunnel oxide passivated contact (TOPCon) solar cells. The deposition parameters, crystal structure, and chemical state were systematically investigated. A higher TiN content and stronger TiN (111) diffraction peak resulted in higher conductivity. We demonstrated that the TiN film possessed a conductivity as high as 5000 S/cm and a relatively low work function of 4.26 eV. An ultra-thin TiN film (1–2 nm) was inserted between the n+ poly-Si and rear electrode to reduce the interface contact resistance and interface barrier height and subsequently obtain better electron transport. The cross-sectional morphology and elemental distribution of the n+ poly-Si/TiN/Ag interface were tested using high-resolution transmission electron microscopy. The developed TiN film was a proof of concept, and it demonstrated an impressive cell efficiency of 24.6% (Voc = 707.1 mV, Jsc = 41.62 mA/cm2, FF = 83.7%) on TOPCon solar cells. Our work provides vital insights and a detailed supplement toward the optimization of electron contact for silicon solar cells or perovskite solar cells. The outcomes of the study indicate the potential for use in applications involving high fill factor photovoltaic devices.

Low Noise Opto-Electro-Mechanical Modulator for RF-to-Optical Transduction in Quantum Communications.

In this work, we present an Opto-Electro-Mechanical Modulator (OEMM) for RF-to-optical transduction realized via an ultra-coherent nanomembrane resonator capacitively coupled to an rf injection circuit made of a microfabricated read-out able to improve the electro-optomechanical interaction. This device configuration can be embedded in a Fabry-Perot cavity for electromagnetic cooling of the LC circuit in a dilution refrigerator exploiting the opto-electro-mechanical interaction. To this aim, an optically measured steady-state frequency shift of 380 Hz was seen with a polarization voltage of 30 V and a Q-factor of the assembled device above 106 at room temperature. The rf-sputtered titanium nitride layer can be made superconductive to develop efficient quantum transducers.

Thermal characterization of Ge-rich GST/TiN thin multilayers for phase change memories

In the domain of phase change memories (PCMs), intensive research is conducted to reduce the programming cycle cost. The RESET operation is done by melting the PCM and then quenching the liquid phase to put it back to the amorphous state. In most of the devices, the heating is realized by the Joule effect with a titanium nitride (TiN) component put in contact with the PCM itself. One of the crucial points to improve the efficiency of this technology is to characterize the thermal contact between TiN and PCM. Having a low thermal resistance between the heater and the PCM ensures the heat transfer between the two is as efficient as possible. In this work, the interfacial thermal resistance between Ge-doped G2Sb2Te5 (GeGST)/TiN in multilayer systems has been characterized, and the influence of the compressive stress exerted by the TiN layers on the GeGST crystallization has been highlighted.

Titanium Nitride Plasmonic Nanohole Arrays for CMOS-Compatible Integrated Refractive Index Sensing: Influence of Layer Thickness on Optical Properties

The combination of nanohole arrays with photodetectors can be a strategy for the large-scale fabrication of miniaturized and cost-effective refractive index sensors on the Si platform. However, complementary metal–oxide–semiconductor (CMOS) fabrication processes place restrictions in particular on the material that can be used for the fabrication of the structures. Here, we focus on using the CMOS compatible transition metal nitride Titanium Nitride (TiN) for the fabrication of nanohole arrays (NHAs). We investigate the optical properties of TiN NHAs with different TiN thicknesses (50 nm, 100 nm, and 150 nm) fabricated using high-precision industrial processes for possible applications in integrated, plasmonic refractive index sensors. Reflectance measurements show pronounced Fano-shaped resonances, with resonance wavelengths between 950 and 1200 nm, that can be attributed to extraordinary optical transmission (EOT) through the NHAs. Using the measured material permittivity as an input, the measured spectra are reproduced by simulations with a large degree of accuracy: Simulated and measured resonance wavelengths deviate by less than 10 nm, with an average deviation of 4 nm observed at incidence angles of 30° and 40°. Our experimental results demonstrate that an increase in the thickness of the TiN layer from 50 to 150 nm leads to a sensitivity increase from 614.5 nm/RIU to 765.4 nm/RIU, which we attribute to a stronger coupling between individual LSPRs at the hole edges with spatially extended SPPs. Our results can be used to increase the performance of TiN NHAs for applications in on-chip plasmonic refractive index sensors.

Properties of CrN/TiN Multilayer Films With Nanoscale Layer Thickness

Chromium nitride (CrN)/titanium nitride (TiN) multilayer films at nanoscale layer thickness were prepared using a combination of reactive high-power impulse magnetron sputtering (HiPIMS) and pulsed magnetron sputtering. Each layer thickness was adjusted by controlling each deposition time. The hardness and Young’s modulus of the multilayer films, which were measured using nanoindentation technique, did not vary significantly with layer thickness. The film hardness ranged between 22 and 24.5 GPa, and the Young modulus was between 300 and 330 GPa. On the contrary, the compressive stress of the multilayer films gradually decreased with the increase in the TiN layer thickness. The friction coefficient of the multilayer film did not depend on the CrN layer thickness, but it reduced drastically to 0.2–0.3 with the increase in the TiN layer thickness in the range of the TiN layer thickness less than about 2 nm.

High-performance p-i-n perovskite photodetectors and image sensors with long-term operational stability enabled by a corrosion-resistant titanium nitride back electrode.

Despite the impressive developments in perovskite optoelectronic devices, their long-term stability remains a major challenge. Chemical reactions and ion exchange at the metal/perovskite contact interface are two significant factors that lead to the failure of perovskite devices. To address this issue, a titanium nitride (TiN) layer is introduced as a robust corrosion-resistant coating between perovskite films and metal electrodes. By introducing TiN layer, a perovskite photodiode with dark current down to 3.25 × 10-11 A cm-2 is realized. Consequently, the TiN-based perovskite photodiode shows a specific detectivity of 1.21 × 1014 cm W-1 Hz1/2, which is approximately two orders of magnitude higher than that of the control device without a TiN layer. Under continuous illumination of a 520 nm green light for 576 000 cycles, the responsivity of the TiN-based photodetector remains at 94.27% of its initial value. The TiN-based photodetector exhibits superior stability under thermal stress. After aging at 85 °C for 572 h, the TiN-based photodetector retains 72% of its initial responsivity. Using the TiN-based photodiode, a perovskite image sensor containing 64 × 64 pixelated perovskite photodiodes is constructed over an amorphous silicon thin-film transistor (TFT) backplane. The perovskite image sensor exhibits real-time imaging capability and long-term stability for over 6 months. This study highlights the importance of using metallic nitrides to achieve high-performance and air-stable perovskite devices for optoelectronic applications.

Metal–ceramic composite structures for fabrication of high power density plasmonic devices

The recent decade brought many advances to plasmonics, but high power density plasmonic antennas designed to behave as heaters or operate in high temperature environments are still facing material stability challenges preventing their ultimate use. Gold has been the optimal choice among plasmonic materials but experiences morphology changes at temperature that result in device efficiency reduction and failure. Bulk titanium nitride has been explored as a solution but has deal-breaking tradeoffs in device quality factor. In this paper, we explore via proof-of-concept the use of a metal–ceramic composite structure to determine whether a bulk Au nanorod can provide strong plasmonic resonances while coated with an ultrathin conformal layer of titanium nitride or silica to provide morphological stability and sufficient plasmonic activity without excessive resonance quality degradation. We show SEM-level morphological stability for temperatures up to 500 °C with coatings below 4 nm. Computer modeling suggests the ultrathin titanium nitride has detrimental effects on the strong plasmonic resonances of a Au nanorod. We then looked into other possible coatings for solutions to stabilize high power density plasmonic antennas including plasmonic oxides, metal adhesion layers, and silica, the latter appearing to be the best option while lowering the overall peak electric field intensity, the silica increases the electric field intensity at its boundary.

Large refrigerant capacity in superparamagnetic iron nanoparticles embedded in a thin film matrix

A magnetocaloric effect (MCE) with sizable isothermal entropy change (ΔS) maintained over a broad range of temperatures above the blocking temperature is reported for a rare earth-free superparamagnetic nanoparticle system comprising of Fe–TiN heterostructure. Superparamagnetic iron (Fe) particles were embedded in a titanium nitride (TiN) thin film matrix in a TiN/Fe/TiN multilayered pattern using a pulsed laser deposition method. High angle annular dark-field images in conjunction with dispersive energy analysis, recorded using scanning transmission electron microscopy, show a clear presence of alternating layers of Fe and TiN with a distinct atomic number contrast between Fe particles and TiN. Quantitative information about the isothermal entropy change (ΔS) and the magnetocaloric effect in the multilayer Fe–TiN system has been obtained by applying Maxwell relation to the magnetization vs temperature data at various fields. With the absence of a dynamic magnetic hysteresis above the blocking temperature, the negative ΔS as high as 4.18 × 103 J/Km3 (normal or forward MCE) is obtained at 3 T at 300 K.

Crystalline flower-like nickel cobaltite nanosheets coated with amorphous titanium nitride layer as binder-free electrodes for supercapacitor application

Fabrication of high-performance supercapacitors involves a three-step strategy - selection of suitable electrode material, optimized morphology, and efficient synthesis approach. For the first time, an integrated synthesis approach using the facile hydrothermal technique (for growing NiCo2O4 nanosheets) followed by vacuum cathodic arc deposition (for depositing thin TiN layers) is used to improve the electrochemical stability of pristine nickel cobaltite (NiCo2O4). The hierarchical flower-like NiCo2O4@TiN nanosheets grown on nickel foam as binder-free electrode shows a high specific capacity of 402.57 Cg−1 at 1 Ag−1, excellent rate capability of 82.8% when current density increases from 1 Ag−1 to 20 Ag−1, and cycling stability of 90% over 2000 charge-discharge cycles. The remarkable electrochemical performance of NiCo2O4@TiN-220/Ni signifies its ample potential for the fabrication of a supercapacitor device. A coin-cell symmetric supercapacitor (CR2032) is assembled using the NiCo2O4@TiN-220/Ni electrodes, which exhibits remarkable electrochemical performance, including a specific capacitance of 178 Fg−1, an energy density of 46.4 Wh kg−1 at a power density of 1363 W kg−1, and a capacitance retention of 129.4% after running 3500 cycles. The enhanced performance can be attributed to the porous morphology with core/shell flower-like nanosheet structure of NiCo2O4@TiN grown on nickel foam. The study also emphasizes a good tuning of crystalline metal oxide (NiCo2O4) with amorphous metal nitride (TiN) as high performing electrode for supercapacitor application.