Nickel Cobalt Research Articles

Enhancing durability of ASTM A416 prestressed steel wires against hydrogen embrittlement

In the face of aggressive environment, cathodic protection shows promise as a solution to reducing the risk associated with corrosion initiation and propagation of prestressed concrete structures. This can be achieved by applying an impressed current to the system that brings the electrical potential of steel members to such a level where localized corrosion does not occur. However, atomic hydrogen that evolves at negative potential can cause hydrogen embrittlement of ASTM A416 steel wires used in prestressed concrete, leading to system failure without warning. To reduce the risks of brittle failures, nickel–cobalt alloy was applied to steel wires. The corrosion properties of the coated specimens were studied in simulated concrete and corrosive environments. The steel wires were also placed in an aggressive environment to predict the time to failure of the samples due to hydrogen embrittlement. A brittle crack developed in wires tested in the as-received condition, but samples coated with the proposed coating passed the embrittlement test. Nickel–cobalt coated specimens not only showed corrosion properties similar to as-received samples, but also did not fail the embrittlement test.

A NARX network optimized with an adaptive weighted square-root cubature Kalman filter for the dynamic state of charge estimation of lithium-ion batteries

Due to the high nonlinearities and unstable working conditions, accurately estimating the state of charge (SOC) by the battery management system (BMS) is a major challenge in ensuring the safety and reliability of lithium-ion batteries in electric vehicles. This paper presents a deep learning network, a nonlinear autoregressive model with exogenous inputs (NARX) network with a closed-loop architecture and transfer learning mechanism, which is optimized using a proposed adaptive weighted square-root cubature Kalman filter (AWSCKF) with a moving sliding window and an adaptive weighing coefficient for SOC estimation of lithium-ion batteries. The proposed AWSCKF method is established through square-root and cubature updates to optimize the statistical value of the state estimate, error covariance, and measurement noise covariance matrices, with the ability to incorporate high nonlinearities to filter out the noise, stabilize, and optimize the final SOC. To evaluate the effectiveness of the optimized NARX network and verify the proposed AWSCKF method, battery tests are carried out using a lithium cobalt oxide battery at various charge-discharge rates and a lithium nickel cobalt manganese oxide battery at temperatures of 0 and 45 °C under five complex working conditions. The SOC accuracy of lithium-ion batteries is enhanced by the hybrid method estimation process, which is based on sensitivity analysis and adaptation to various working conditions. The comprehensive results show that the proposed NARX-AWSCKF model achieves the overall best mean absolute error, root mean square error, and mean absolute percentage error values of 0.07293%, 0.0912%, and 0.40356%, respectively, under various complex conditions. By effectively utilizing battery domain knowledge for real-world BMS applications, the proposed model outperforms other existing methods in terms of high effectiveness, robustness, and potential to boost the NARX performance.

Growth of vertically aligned nanosheet-like structured nickel–cobalt hydroxide thin films and their electrochemical properties

Growth of vertically aligned nanosheet-like structured nickel–cobalt hydroxide thin films and their electrochemical properties

Grain Analysis of Ncm Cathode Materials By Astar Technique and Its Effect on Battery Performance

Lithium-ion batteries (LIBs) are one of the most promising energy storage systems for portable electronic devices, electric vehicles, and renewable energy systems. Among the various cathode materials for LIBs, nickel cobalt manganese (NCM) oxide has attracted considerable attention due to its high specific capacity, good cycling stability, and appropriate cost for commercialization. However, Ni-rich NCM (Ni >80%) showed poor cyclability and huge gas evolution because of surface instability.Single crystal NCM has been suggested as a solution to these issues due to its excellent properties. However, it is difficult to quantify the degree of single crystallinity because it is so far subjective. In this study, we employed ASTAR technique (transmission electron microscopy combined with electron backscatter diffraction) to investigate the microstructural features of NCM cathode materials. Our ASTAR analysis showed that NCM cathode materials consist of complex grain and grain boundary structures with varying orientations and sizes. By analyzing the grain size and its morphology, we were able to define the single crystallinity of NCM cathode materials, including the poly NCM and single crystal NCM particles.Furthermore, we found that the grain size and its distribution significantly affects the battery performance and lifespan of NCM cathode materials. Specifically, the poly NCM particles exhibited a larger grain boundary and surface area compared to the single crystal NCM particles. The poly NCM particles also showed a faster DC-IR increase and a shorter lifespan than the single crystal NCM particles, indicating that the grain size has a critical influence on the battery performance and lifespan of NCM cathode materials.Our results provide insights into the design and optimization of NCM cathode materials for next-generation LIBs. By controlling the grain size and its distribution of NCM cathode materials, it is possible to enhance the battery performance and lifespan. Therefore, our study highlights the importance of understanding the microstructural features of NCM cathode materials for developing high-performance and stable LIBs.

Enhanced saturation magnetization in La3+ doped NiCo ferrites prepared by sol–gel auto-combustion method

Lanthanum doped nickel–cobalt nano ferrites with chemical formula Ni0.5Co0.5LaxFe2–xO4 (x = 0.05, 0.10, 0.15 and 0.20) were prepared using a simple sol–gel auto combustion method. The basic structural properties were determined by X-ray diffraction method and the formation of single phased spinel ferrite was confirmed. The crystalline size decreased from 25 to 11 nm and lattice parameter a increases with increase of La doping. The surface morphology of these ferrites was observed by field-emission scanning electron microscopy (FESEM) and agglomerated irregular grains are observed with increase of the rare earth element La doping. Energy-dispersive X-ray spectroscopy (EDX) result confirms the presence of the required elements. The Fourier transform infrared spectroscopy (FTIR) spectrum indicates the formation of the spinel ferrite structure with M−O bonds. Optical direct band measurements from ultraviolet–visible spectroscopy (UV-Vis) spectroscopy indicate that the direct band gap decreases from 1.39 to 1.19 eV for x = 0.05 to x = 0.15, then increases to 1.28 eV for x = 0.20. The room temperature magnetic properties of these ferrites were studied by a vibrating sample magnetometer (VSM). The enhanced saturation magnetization of 49.73 emu/g is observed for x = 0.10 and then saturation magnetizations are gradually decreased for x = 0.15 and x = 0.20. Interestingly the remanent magnetization and coercivity also follow the same trend.

Cobalt and holmium co-doped nickel ferrite nanoparticles: synthesis, characterization and photocatalytic application studies

Abstract Herein, nickel ferrite-based photocatalysts with enhanced light utilizing electrical charge transport properties have been reported for environmental remediation applications. The cobalt and holmium co-doped nickel ferrite [Ni1−x (Co) x Fe2−y (Ho) y O4] nanoparticles and bare nickel ferrite (NiFe2O4) nanoparticles have been prepared via surfactant-supported wet-chemical techniques. The as-prepared ferritic photocatalyst’s structural, morphological, and light harvesting features have been examined in detail using well-known physical, electronic, and optical methods. The co-doped ferrite photocatalyst’s tuned structural features enable it to absorb maximum wavelengths from the U.V. and visible regions. This is because the co-doped Ni1−x (Co) x Fe2−y (Ho) y O4 optical band gap is 1.73 eV; hence, the wavelength from the visible part possesses sufficient energies to trigger the electronic excitation in co-doped ferrite photocatalysts. Moreover, the co-doping-induced structural defects in the ferrite photocatalyst. These defects act as a reservoir for the charge species, mainly electrons, so the process of charge recombination is almost hampered for the Ni1−x (Co) x Fe2−y (Ho) y O4 photocatalyst. In application terms, the photomineralization capabilities of doped and bare ferrite photocatalysts have been explored using crystal violet (CV) dye. The comparative photocatalytic evaluation of both nickel ferrite-based photocatalysts shows that co-doped ferrite degraded 96.02 % of CV dye. In comparison, the undoped one only degraded 64.84 % after 80 min of W-lamp light exposure. The results demonstrated that the Ho and Co co-doped ferrite photocatalyst exhibits excellent photocatalytic activity, suggesting its potential for environmental remediation applications in textile industrial discharges.

A bi-functional catalyst strategy to selectively regulate sulfur redox kinetics in lithium–sulfur batteries

Designing electrochemical catalysts has become a research hotspot due to their accelerating the polysulfide conversion of the sulfur cathode to inhibit the “shuttle effect” in lithium–sulfur batteries. However, it is still a great challenge to design the heterogeneous selective electrochemical catalyst for inhibiting the “shuttle effect”. Herein, nickel cobalt phosphide and cobalt phosphide as the heterogeneous catalyst active sites embedded in the nitrogen-doped hollow carbon nanocages (NiCoP@CoP/NC) are reported, used for multi-step and multi-phase sulfur electrode reaction, and it is found that metal-sulfur d-p hybridization can effectively indicate the intrinsic catalytic activity of metal site. Division of labor and cooperation of the bi-active NiCoP@CoP as heterogeneous catalysts propel the stepwise polysulfide conversion. NiCoP and CoP sites preferentially accelerate the long-chain polysulfide conversion reaction (S8⇌LiPSs) and the short-chain polysulfide conversion reactions (LiPSs⇌Li2S), respectively. Moreover, the hollow and porous N-doped carbon structure can successfully suppress the volume effect and improve the conductivity of the sulfur cathode. The unique design can obtain an effective inhibition of the shuttle effect and rapid electrode reaction. As a result, LiS batteries demonstrate a high initial capacity of 1063 mAh g−1 and a low-capacity decay of 0.04% per cycle within 1000 cycles. Our work provides a feasible idea for the design of host materials in Li–S batteries.

Synthesis of nickel cobalt sulfide on Ni foam for improved electrochemical energy storage: Effect of binder-free reverse pulse potentiostatic electrodeposition and redox additive

Nickel cobalt sulfide (Ni-Co-S) was grown on 3D conductive Ni foam (NF) using binder-free electrochemical deposition to serve as a positive electrode (NCS@NF) for electrochemical energy storage application. Multiple cycles of reverse pulse potentiostatic electrochemical deposition (RPP-ED) were systematically applied to study their influence on the physico-chemical properties of NCS@NF. During the 300 optimized RPP-ED cycles uniform mesoporous interconnected nanoflakes of Ni-Co-S were formed on NF. The NCS@NF electrode demonstrated remarkable electrochemical storage performance, achieving a maximum areal capacity of 0.590 C cm−2 (590 C g−1) in 2 M KOH electrolyte. This remarkable property of NCS@NF can be associated with the improved ionic diffusion at the interconnected nanoflake structure and improved redox transitions at the active sites of nanoflakes. Moreover, the addition of K4(CN)6 as a redox additive improved the areal capacity of NCS@NF to 2.56 C cm−2 (2560 C g−1). Furthermore, an aqueous hybrid supercapacitor was assembled by integrating activated carbon on NF as the negative electrode, while employing NCS@NF as the positive electrode. The aqueous hybrid supercapacitor exhibited an enhanced charge-discharge potential of 1.5 V and demonstrated remarkable stability, maintaining 89% of its performance over 10,000 cycles. Notably, it achieved maximum energy and power densities, 33 μWh cm−2 and 6019 μW cm−2, respectively. These results establish its suitability for hybrid supercapacitor applications.

Enhanced pseudocapacitive behaviour in laser-written graphene micro-supercapacitors decorated with nickel cobalt sulphide nanoparticles

The next generation of energy storage technologies requires enhanced fabrication techniques such as the use of CO2 infrared lasers to pattern micro-supercapacitor (MSC) electrodoes. This study reports direct-writen laser-induced graphene (LIG) micro-supercapacitors with electrodepositated NiCo2S4- nanoparticles on commercial polyimide sheets. X-ray photoelectron spectroscopy (XPS) combined with transmission electron microscopy (TEM) showed NiCo2S4 nanoparticles decorating the graphene, within a highly porous carbon-based electrode. The LIG/NiCo2S4 exhibited outstanding properties with a specific capacitance of 30.4 mF cm−2 at 0.75 mA cm−2 and an energy density of 16.9 µWh cm−2 at a power density of 367.5 µW cm−2. High capacitance retention of 1.22-fold was measured after 5000 cycles of charge/discharge, and of ∼90% when bent to 120˚ angle. Here, it is demonstrated that surface decoration is an effective route in improving LIG MSC storage properties, and that the LIG/NiCo2S4 MSC is suitable for use in next generation of flexible and miniaturized portable devices.

Fabrication of super-high energy density asymmetric supercapacitor prototype device employing NiCo2S4@f-MWCNT nanocomposite

Materials with high porosity, high redox activity and rich electrochemically active sites are promising candidates for pseudocapacitance. Among the bimetallic sulphides of transition metals, nickel cobalt sulphide (NiCo2S4; NCS) is a promising pseudocapacitive material. NiCo2S4 (NCS) can be coupled with carbonaceous material such as functionalised multiwalled carbon nanotubes (NCS@f-MWCNT) to further enhance the electrochemical characteristics such as high charge-storage capacity, improved charge-discharge characteristics, stability and rate performance. In this line, bare NiCo2S4 (NCS) and functionalized multiwalled carbon nanotubes (f-MWCNT) loaded NiCo2S4 nanoparticles were synthesized by hydrothermal method by employing hexadecyltrimethylammonium bromide (CTAB) as surfactant. X-ray diffraction studies confirmed the formation of cubic phase of NiCo2S4 and transmission electron microscopic study revealed the formation of NCS@f-MWCNT nanocomposite. The XPS findings confirmed the co-existence of Ni3+, Ni2+, Co3+, and Co2+ species in both the NCS and NCS@f-MWCNT samples. Cyclic voltammetry analysis was performed to determine the respective impacts of the surface adsorption and diffusion-mediated processes on the charging/discharging kinetics. The incorporation of f-MWCNT into NCS led to improved overall charge storage kinetics, demonstrating a promising avenue for developing low-cost cathode materials for high-performance hybrid battery-type materials with both high power and energy densities. Bare NiCo2S4 showed a specific capacitance of ~899 Fg−1 at 1 Ag−1 with a capacitance retention of ~52 %. While NCS@f-MWCNT exhibited a high charge storage capacity of ~1360 Fg−1 with capacitance retention of 89 % at 10 Ag−1. An asymmetric coin cell devices were fabricated using NCS@f-MWCNT as a positive electrode and an activated carbon, reduced graphene oxide ((ASC2) or carbon fiber (ASC3) as negative electrodes. Among them, the NCS@f-MWCNT//AC (say ASC1) showed outstanding charge storage characteristics with a capacitance of ~109.9 Fg−1, energy density ~ 78.3 Whk g−1 and power density ~ 800 Wk g−1 at 1Ag−1. The presented analysis has demonstrated that a hybrid structure made of highly conductive materials like functionalized multiwall carbon nanotubes could be employed to synergistically enhance the electrochemical performance of NiCo2S4.

Influence of Additives on the Mechanical Characteristics of Hardox 450 Steel Welds.

The aim is to overcome the issues of high-hardness material welding by different additives used to achieve the desired improvements. The research is focused on Hardox 450 steel welding and factors to be considered in order to maintain the required mechanical properties of the weld. The selection of best suited welding materials or additives, including filler metals and shielding gases, are within the important factors to be taken into account. During the welding of Hardox 450 steel, cobalt, nickel, tungsten and titanium additives and cobalt and tungsten mixture additives were used and their influence on the microstructure and mechanical properties of the fusion and heat-affected zones was investigated. The microstructure of the weld zone is related to certain mechanical properties of the weld and heat-affected zone, such as hardness, tensile and bending strength, yield strength, strain at ultimate tensile strength, the Young's modulus and elongation. Research has shown significant differences in the mentioned parameters depending on specific additives used in the welds. It can be concluded that tungsten, used as an additive, increased the hardness of the heat-affected and fusion zones up to 478 HV; the combined presence of cobalt and tungsten additives improves the strength of the seam up to 744 MPa during tensile; and in the case of bending, nickel, when used as an additive, increased ductility (the bending modulus reached the limit of 94 GPa) and at the same time, decreased the risk of cracking. The obtained results highlight the possibilities for strengthening the welded joint of Hardox 450 steel using different additives or their mixtures. The research conclusions and recommendations aim at improving the quality and mechanical properties of welded Hardox 450 steel joints in various applications.

Magnetically Triggered Interplay of Capacitive and Diffusion Contributions for Boosted Supercapacitor Performance.

The chemistry involved in supercapacitors in terms of their mechanistic contributions leading to improved specific capacity will aid in easy commercialization. The main contributory factors in a supercapacitor are either capacitive (non-diffusion controlled) or ion-diffusion behavior, which results in enhanced charge-discharge characteristics of a supercapacitor reflected in its power density, whereas ion-diffusion behavior will lead to the enhanced energy density of a supercapacitor. In this context, the present article attempts to understand the use of external magnetic fields, leading to the interplay between capacitive and ion-diffusion behavior in a high-performance supercapacitor. The model system chosen in the present study, nickel cobalt copper carbonate hydroxide (NiCoCuCH), can effectively address the interplay between capacitive and ion diffusion contributions by varying total magnetic effects involving magnetic dilution. The magneto-enhancement of the electrodes nickel cobalt copper carbonate hydroxide (NiCoCuCH) and aluminum-doped nickel cobalt copper carbonate hydroxide (Al-NiCoCuCH) was demonstrated under the magnetic field from 0 to 250 mT. Both NiCoCuCH and Al-NiCoCuCH show dominant non-diffusion-controlled (capacitive) and diffusion-controlled behavior as a function of the applied external magnetic field. Under the influence of the external magnetic field, ferromagnetic coupling between metal-oxygen-metal centers via oxygen 2p orbitals enhances, leading to a facile redox pathway. To further control the charge-discharge behavior of the electrode via the interplay between diffusive and capacitive, a non-magnetic ion, Al3+, was doped into the bare metal carbonate hydroxide crystal lattice. The Al3+ ion not only alters the crystal symmetry but also restricts the alignment of the magnetic domains in the electrode, leading to a sluggish redox pathway, effectively increasing the capacitive contribution, and leading to improved charge-discharge characteristics at the expense of energy density. We have constructed an asymmetric device with the best-performing (110 mT) NiCoCuCH electrode as a positive electrode and activated carbon as a negative electrode. The NiCoCuCH/AC ASC device at 110 mT has the largest specific capacity (1100 C g-1 at 2 A g-1) at 110 mT, leading to a high energy density (250 W h kg-1) and a power density (1.7 kW kg-1) of the electrode.

Design of Highly Efficient Nickel-Cobalt-Manganese-Molybdenum (NCMM) Nano-Catalysts Supported on Activated Carbon for Desulfurization Process

To maintain a healthy environment and way of life in the modern world, clean fuel must be produced. It is important to totally and successfully remove sulfur-containing harmful compounds from fuel oil in order to comply with the new sulfur legislation. Numerous methods have been proposed in the literature for desulfurizing fuel oil. In this study, activated carbon (AC), which is regarded as a significant porous material, is derived from agro-wastes such as apricot shells (AS) and is loaded with different combinations of active metals. Nickel–Cobalt–Manganese (NCM) over AC is firstly prepared and evaluated experimentally. Then, several concentrations of Molybdenum (1%, 2% and 3%) are separately added to NCM to generate three novel composite mesoporous nano-catalysts (NCMM_1, NCMM_2 and NCMM_3). Several tests have been carried out to determine the catalysts’ properties, such as BETsurface area, pore volume, FTIR, TGA and SEM, XRF and XRD. These catalysts are then used in the batch oxidative desulfurization process to remove sulfur compounds from wide cut oil (from IBP to 345 °C). The pilot plant conditions were as follows: air flow rate = 120 L/h, reaction temperature = 363 K and reaction time of 1 h for all catalysts. Remarkable characteristics have been noticed, and it was discovered that the nano-catalyst NCMM_2 performed better in terms of degree of sulfur removal compared to other nano-catalysts.

Assessing resource depletion of NCM lithium-ion battery production for electric vehicles: An exergy-based perspective

Electric vehicles (EVs) play an important role in the low-carbon transition of transportation, and lithium-ion battery (LIB) is a key component of EVs. Because of the high demand for energy and critical metals for LIB production, it is necessary to quantify the associated resource consumption intensity from multiple perspectives. In the present study, the exergy derived from the second law of thermodynamics was applied to assess the abiotic resource depletion associated with lithium nickel cobalt manganate (NCM) battery production, including NCM111, NCM523, NCM622, and NCM811. For comparability of results, the functional unit was defined as 1 kWh NCM power pack. The results showed that the cumulative exergy demand (CExD) value of the NCM523 pack production is 2857.56 MJ/kWh, with the cathode material manufacturing process accounting for 56.77% because of the significant contribution of CoSO4. The CExD of battery production can be effectively reduced by reducing cobalt use and adding a solvent recovery device. The supply stage of upstream raw and auxiliary materials is the key to CExD reduction. The comparison results indicated a significant reduction in the CExD of Ni-rich NCM batteries due to improvement in energy density and reduction in cobalt demand. In addition, the comparison of abiotic resource depletion characterization results and method characteristics among the CExD, ReCiPe, and CML-IA methods showed that using CExD has clear advantages with regard to objectivity and long-term stability in the evaluation of rapidly innovated battery products. Applying exergy-based accounting methods for resources contributes to a scientific understanding of abiotic depletion levels and improves resource efficiency in the relevant industries.

H2O2-assisted fabricate nickel cobalt sulfide as the efficient catalyst for the novel strategy of 5-hydroxymethylfurfural stepwise electrolysis

Electrooxidation of 5‑Hydroxymethylfurfural (HMF) is considered a promising strategy for replacing the sluggish oxygen evolution reaction (OER) of electrolytic water, which can reduce the consumption of hydrogen production and the risk of gas mixing and obtain value-added products. Herein, a nanosheet with nanoflower catalyst (H-0.3Co-Ni3S2) was synthesized via a one-step hydrothermal process with the assistance of hydrogen peroxide (H2O2) for the electrooxidation of HMF. Adding H2O2 and Co can decrease Ni's outer layer electronic cloud density, which benefits the catalyst's oxidation and catalyzes the HMF electrooxidation. H-0.3Co-Ni3S2 shows the superior performance of the HMF electrochemical oxidation with the initial potential of 1.25 V vs. RHE and the voltage of 1.38 V vs. RHE at 200 mA cm−2 under the electrolyte of 1 M KOH with 10 mM HMF. The conversion rate, yield and Faraday efficiency of HMF electrooxidation for H-0.3Co-Ni3S2 in the electrolyte of 1 M KOH with 10 mM HMF are 98.2 %, 97.6 % and 97.6 %, respectively. Besides, we provide a novel stepwise electrolysis strategy that can inhibit OER effectively while electrolyzing large-concentration HMF rapidly. Finally, in an electrolyte of 1 M KOH with 30 mM HMF, the conversion rate, yield and Faraday efficiency achieve 100 %, 91.9 % and 97.4 %, respectively.

Urchin-like alkaline nickel–cobalt carbonate derived Ni3S4/Co3S4 nanoparticles anchored on rGO for lithium/sodium-ion batteries with enhanced capacity

Transition metal sulfides (TMS) have emerged as promising anode materials for lithium and sodium ion batteries due to their high theoretical capacity and low cost. However, the severe volume expansion during the conversion reaction causes rapid collapse inevitability when used as anode material. Herein, we pertinently fabricated nanoscale Ni3S4/Co3S4 with uniform particle size homogeneously dispersed between pleated graphene (Ni3S4/Co3S4@rGO) through facile hydrothermal assisted by cationic surfactants. The construction of 3D nanocomposites significantly shortens ion migration distances and enriches electronic pathways, accelerating charge transfer kinetics while maintaining good stability. Uniformly distributed bimetallic sulfides and rGO limit each other's aggregation, allowing the excellent structural properties of the material to be maintained over time. Thus, the Ni3S4-Co3S4@rGO electrodes deliver a high reversible capacity of 972.5 mAh/g upon 200 cycles at 100 mA g−1 in Lithium-ion battery and 487.5 mAh/g upon 150 cycles at 100 mA g−1 in Sodium-ion battery, as well as excellent rate capacity in both. These excellent properties show the potential for expansion of this simple synthetic method in the field of alkali metal batteries.

A Hybrid Supercapacitor from Nickel Cobalt Sulfide and Activated Carbon for Energy Storage Application

Nickel–cobalt sulfide is a promising material for supercapacitor positive electrodes due to its high theoretical capacitance. Herein, the electrochemical properties of nickel–cobalt sulfide nanostructures synthesized via a two‐stage hydrothermal method are investigated and the synthesis conditions to achieve high mass loading while maintaining high specific capacitance are determined. The nanostructural morphology and effective mass loading of the electrodes (≈10 mg cm−2) enable the achievement of a high specific capacitance value of 8.1 F cm−2 at a current density of 5 mA cm−2. A hybrid capacitor is made using optimized nickel–cobalt sulfide electrodes as the positive electrode and activated carbon as the negative electrode. The device exhibits a maximum operation potential window of 1.75 V and an energy density of 51.2 Wh kg−1 at a power density of 262.5 W kg−1. Electrochemical measurements demonstrate that the device maintains a capacitance retention rate of 95% after 10 000 charge–discharge cycles within a working voltage of 1.8 V. High electrochemical performances compared with others devices‐based water electrolytes make it promising for the energy storage device.

Accommodating physical reaction schemes in DSC cathode thermal stability analysis using chemical reaction neural networks

With the increasing demand for applications in vehicles and energy storage systems, lithium-ion batteries have attracted extensive research interest. Thermal runaway in these batteries, which can lead to rapid temperature rise, flammable gas release, and even fires, directly imposes safety concerns. Previous studies have utilized differential scanning calorimetry (DSC) to infer thermal kinetic mechanisms for individual battery components. However, the commonly used Kissinger analysis involves oversimplified assumptions which lead to erroneous quantification of the kinetic parameters and inaccurate physical interpretation of the results. Here, we propose an extension of the recently developed Chemical Reaction Neural Network (CRNN) framework that is not limited by the simplifications from traditional optimization methods and can learn complex, multi-step thermal kinetics from DSC data. After a proof of concept, we leverage this novel approach to improve recent thermal decomposition models for nickel–cobalt–manganese oxide (NCM) cathodes. Its generality and enhanced learning capability enable improved models with better agreement to the data that account for the actual physical coupling between multi-step reaction pathways. The successful development of the CRNN approach to learn such thermal kinetic models from simple DSC data demonstrates its potential to advance thermal runaway modelling for lithium-ion batteries and other complex kinetic systems.

Facile synthesis of NiCo@rGO as bifunctional electrocatalyst for enhanced water splitting

Rapid depletion of fossil fuels and growth of greenhouse gases necessitates the shift toward renewable energy sources. Electrocatalytic water splitting in this regard has proven to be one of the best options for producing hydrogen gas as a fuel for generating electricity. Since the scarcity and high cost diminish the commercial use of noble metal catalysts, this study utilizes environmental friendly, stable, and cost-effective nickel cobalt over reduced graphene oxide electrocatalysts for efficient hydrogen evolution reaction and oxygen evolution reaction activities at low overpotential to give benchmark density of 10 mAcm−2. Among the synthesized nanocomposites rGO-NiCo10% and rGO-NiCo15% showed enhanced oxygen evolution reaction activity producing a current density of 80 mAcm−2 and 50 mAcm−2 at overpotential 620 mV with low Tafel slopes 123.27 mVdec−1 and 141.41 mVdec-1 respectively, comparing to activity of RuO2. Similarly, they produced a current density of 20.5 mAcm−2 and 13.1 mAcm−2 at overpotential 490 mV for hydrogen evolution reaction with low Tafel slope values 67.67 mVdec−1 and 92.79 mVdec−1. Electrochemical impedance spectroscopy analysis suggested feasible charge transfer kinetics at the catalyst-electrolyte interface with small Rct values channeling it to improve electrochemical performance.

Manganese doped cobalt–nickel spinel ferrite via. sol–gel approach: Insight into structural, morphological, magnetic, and dielectric properties

Manganese doped cobalt–nickel spinel ferrite via. sol–gel approach: Insight into structural, morphological, magnetic, and dielectric properties