Calcination Time Research Articles

Low Temperature and Rapid Synthesis of Li‐Rich Li(Li0.17Mn0.83)2O4 Spinel Cathodes Derived from Metal‐Organic Frameworks for Lithium‐Ion Batteries

AbstractLi‐rich spinel materials (Li1+xMn2−xO4) have shown promise for lithium‐ion batteries. Nevertheless, the preparation of Li1+xMn2−xO4 faces significant challenges due to the difficulty in achieving a balance between well‐crystallized phases and stoichiometric chemistry. Moreover, the synthesis process is highly sensitive to calcination temperature and time, making it susceptible to phase transformations. Therefore, the rational selection of precursors and corresponding calcination procedures is absolutely essential. Herein, we make full use of the nature of metal‐organic frameworks (MOFs) to achieve phase‐controlled synthesis of Li(Li0.17Mn0.83)2O4 (LMO−F) spinel cathodes in 8 minutes at 500 °C. The composition and structural evolution during the pyrolysis process were systematically investigated to clarify the relationship between precursors and derivatives. Notably, the LMO−F achieved good electrochemical performance with 100.4 mAh g−1 at 50 mA g−1 after 100 cycles.

Characteristics of Solid Mineral Phase Transitions During Sulfuric Acid Production from Gaseous-Sulphur-Reduced Gypsum

The acid co-production of cement is a prominent research focus for the large-scale, high-value utilization of phosphogypsum in the context of dual-carbon strategies. This paper builds on extensive research conducted by its authors on the co-production of sulphoaluminate cement clinker through acid production from gaseous-sulphur-reduced phosphogypsum. The solid mineral phase transformations occurring in the kiln during this process are systematically studied, and the effects of various calcination regimes (temperature, time, and atmosphere) on the evolution of clinker mineral phases are elucidated. This paper provides basic data support for the gas-sulfur-reduced phosphogypsum-acid cogeneration of sulfoaluminate cement clinker processes, and promotes the realization of the large-scale high-value utilization of phosphogypsum resources. The generation of the clinker mineral phase anhydrous calcium sulphoaluminate (C4A3S̅) begins at 1100 °C. Increasing the calcination temperature and extending the calcination time promote C4A3S̅ formation. However, when the calcination temperature exceeds 1350 °C, C4A3S̅ decomposes, leading to the formation of low-activity C2AS. In a CO atmosphere, the main mineral phases in the clinker transform into C2AS and 12CaO·7Al2O3, owing to the decomposition of CaSO4, which inhibits C4A3S̅ formation. At calcination temperatures exceeding 1300 °C, a significant amount of C2AS appears in the calcined material, and 12CaO·7Al2O3 begins to form.

Catalytic ozone oxidation performance of Fe-Ce@γ-Al2O3 in reverse osmosis concentrate treatment

The reverse osmosis concentrate (ROC) produced in the process of textile wastewater treatment has a high salt content, posing a significant environmental threat. In this study, catalytic ozone oxidation was used to treat ROC, which initially had a chemical oxygen demand (COD) of 127.38 mg/L. The Fe-Ce@γ-Al2O3 catalysts had the best performance under the Fe/Ce doping ratio of 3:1, calcination temperature of 500 °C with calcination time of 4 h. SEM and XRD analyses confirmed the successful loading of Fe and Ce on γ-Al2O3. The catalytic ozone oxidation conditions were optimized by the response surface method (RSM). Under the optimal reaction conditions (catalyst dosage of 139.07 g/L, ozone ventilation rate of 1.65 L/min, and initial pH of 9.86), the actual COD removal rate reached 89.21 %. Three-dimensional fluorescence spectroscopy was used to analyze the degradation mechanism of dissolved organic matter (DOM) during the treatment of ROC. Three-dimensional fluorescence spectrum (3DEEM) results demonstrated the obvious degradation of DOM in ROC after the catalytic ozone oxidation treatment. The COD removal rate remained at approximately 80 % after 10 recycles, indicating that the Fe-Ce@γ-Al2O3 catalyst had good catalytic stability and reusability. In summary, the Fe-Ce@γ-Al2O3 catalysts demonstrate sustained practical effectiveness and high catalytic efficiency, making them suitable for the treatment of ROC.

Tuning Na Occupation and Annealing Temperature on Na Diffusion Pathways in P2-Type NaxNi0.25Mn0.75O2 for Sodium-Ion Batteries by Ab Initio Calculations.

The NaxNi0.25Mn0.75O2 cathode material draws ongoing interest owing to its considerable specific capacity along with its elevated average operating voltage. However, its application is limited by weak rate performance and quick capacity fading. In this study, a series of NaxNi0.25Mn0.75O2 (x = 0.65, 0.70, 0.75, 0.80) cathode materials are prepared by the solid-phase method based on an orthogonal experiment. The optimum preparation process is investigated by optimizing factors such as Na content, calcination temperature, calcination time, and heating rate. The Nae/Naf ratio is adjusted, and the Na+ at different sites are rearranged to reduce the Na+/vacancy ordering by changing the Na content on the basis of process optimization. Owing to the fast migration kinetics of Nae sites, experimental results indicate that the P2-Na0.75Ni0.25Mn0.75O2 cathode material, which has Na+ occupying more thermodynamically stable Nae sites, demonstrates superior battery performance. High initial discharge specific capacity (157.2 mAh g-1) along with favorable cycle performance of the Na0.75Ni0.25Mn0.75O2 cathode material can be achieved by modifying the Nae site occupancy and optimizing the experimental conditions. Together with the microscopic control of Na+ occupancy, this novel orthogonal experiment design offers a fresh perspective and approach to a thorough comprehension of cathode materials for sodium-ion batteries.

Preparation and performance of catalyst for organic peroxide wastewater treatment

To improve the oxidation pretreatment efficiency of wastewater from organic peroxides, a catalyst (CeO2-C catalyst) was developed using the calcination method with ceramic particles as the support. The crystalline structure and elemental composition of the CeO2-C catalyst were characterized by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), and X-ray diffraction (XRD). This study explored the effects of CeO2 mass ratio, calcination temperature, and calcination time on the performance of the catalyst. The optimal preparation conditions were established through orthogonal experiments. Additionally, the synergistic effect of the catalyst on the ozone oxidation treatment of peroxide wastewater was investigated. The results indicated that the optimal preparation parameters were a CeO2 mass ratio of 4 %, a calcination temperature of 500 °C, and a duration of 5 h, respectively. After five cycles of reuse, the catalytic activity slightly decreased but remained relatively stable. With an ozone flow rate of 6 L/min, the CeO2-C/ozone catalytic oxidation process achieved a Chemical Oxygen Demand (COD) removal rate of 28.11 % in wastewater, and the B/C (the ratio of BOD concentration to COD concentration) of wastewater improved from 0.093 to 0.152. The calcination method proved effective for preparing the CeO2-C catalyst, which demonstrated significant catalytic performance and held promising application prospects in the oxidation pretreatment of organic peroxide wastewater.

Modeling and Optimization of Sisal Fiber Degradation Treatment by Calcined Bentonite for Cement Composite Materials

ABSTRACT The treatment of sisal fiber by pozzolanic materials like kaolin and silica-fume has been explored; however, no study has modeled and optimized the effect of sisal fiber degradation treatment using calcined bentonite. Therefore, the present study investigate the effects of treating sisal fiber with different doses of calcined bentonite, bentonite calcination temperatures, and times on fiber breaking load, degradation resistance, and water absorption using the central composite design-response surface method (CCD-RSM). The best performance of the optimum treated sisal fiber selected from the CCD-RSM based on the established goal of maximizing breaking load and degradation resistance with minimum water absorption, it was obtained a calcined bentonite dose of 30.067%, a bentonite calcination temperature of 800°C, and a calcination time of 179.99 min. Based on these factors, experimentally found sisal fiber breaking load 12.87 N, degradation resistance 98.44%, and water absorption 39.05%, all are within the 95% confidence level compared to the optimum numerical suggested values. Hence, the optimum treated sisal fiber improved breaking load by 33.37% and degradation resistance by 98%, while it reduced water absorption by 60.95%, compared to raw sisal fiber. Besides these, the optimum treated sisal fiber exhibits higher surface roughness and lower porosity than the raw sisal fiber.

Multifunctional nanoplatforms based on alumina-coated mesoporous silica with potential for cancer theranostics applications

Multifunctional nanoplatforms based on mesoporous silica coated with alumina were successfully and sustainably synthesized using sodium silicate extracted from rice husk ash (RHA), demonstrating the potential for cancer theranostics. The hybrid nanostructures produced (C2-600 and C4-600), from two different calcination times, exhibited distinct morphologies, textural parameters, and degrees of mesoscopic organization. As expected, the Al2O3 coating on the mesoporous silica nanoparticles (MSNs) reduced the specific surface area from 720 m2/g to 122 m2/g (C2-600) and 57 m2/g (C4-600), while preserving their mesoporous structure. Additionally, both C2-600 and C4-600 showed relatively good stability across a wide pH interval, with a zeta potential of ζ = -15 mV and hydrodynamic diameter (Dh) ranging from 160 to 670 nm, depending on the pH of the medium. These peculiar characteristics resulted in high encapsulation efficiency (EE ≈ 90%) for the doxorubicin (DOX) anticancer drug, as well as sustained drug release in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4). Appreciably, C4-600-DOX released approximately 83% of the drug over 96 hours and demonstrated significant biodegradation in simulated biological media. Furthermore, the hybrid nanoplatforms exhibited strong optical absorption between 250 and 420 nm, along with broad and intense photoluminescence (PL) in the near-infrared (NIR) region (680-900 nm), which is highly desirable for NIR-fluorescence diagnostic imaging. Notably, the hybrid nanoplatforms without DOX were non-cytotoxic to fibroblast and Caco-2 cells, while the DOX-loaded nanoplatforms exhibited selectivity and potent anticancer activity, inhibiting approximately 80% of Caco-2 colorectal cancer cells after 72 hours. These findings demonstrate that C2-600 and C4-600 are innovative, multifunctional and biodegradable nanoplatforms with powerful potential as drug carriers and fluorescence imaging agents, making them promising candidates for cancer theranostics.

Preparation of Co-Ce@RM catalysts for catalytic ozonation of tetracycline.

In this work, a Co-Ce@RM ozone catalyst was developed using red mud (RM), a by-product of alumina production, as a support material, and its preparation process, catalytic efficiency, and tetracycline (TCN) degradation mechanism were investigated. A comprehensive assessment was carried out using the 3E (environmental, economic, and energy) model. The optimal production conditions for Co-Ce@RM were as follows: The doping ratio of Co and Ce was 1:3, the calcination temperature was 400°C, and the calcination time was 5h, achieving a maximum removal rate of 87.91% of TCN. The catalyst was characterized using different analytical techniques. Under the conditions of 0.4L/min ozone aeration rate, with 9% catalyst loading and solution pH9, the optimal removal rates and chemical oxygen demand by the Co-Ce catalytic ozonation at RM were 94.17% and 75.27%, respectively. Moreover, free radical quenching experiments showed that superoxide radicals (O2 -) and singlet oxygen (1O2) were the main active groups responsible for the degradation of TCN. When characterizing the water quality, it was assumed that TCN undergoes degradation pathways such as demethylation, dehydroxylation, double bond cleavage, and ring-opening reactions under the influence of various active substances. Finally, the 3E evaluation model was deployed to evaluate the Co-Ce@RM catalytic ozonation experiment of TCN wastewater. PRACTITIONER POINTS: The preparation of Co-Ce@RM provides new ideas for resource utilization of red mud. Catalytic ozonation by Co-Ce@RM can produce 1O2 active oxygen groups. The Co-Ce@RM catalyst can maintain a high catalytic activity after 20 cycles. The degradation pathway of the catalytic ozonation of tetracycline was fully analyzed. Catalytic ozone oxidation processes were evaluated by the "3E" (environmental, economic, and energy) model.

New insights into the combined effect of steam and SO2 on CaCO3 decomposition: Experimental study and DFT calculation

Calcium cycling is a second-generation CO2 capture technology characterized by rapid development and high technical maturity. In practical applications, steam and SO2 are commonly present in the calcination reactor due to the oxygen-rich combustion of coal. Previous studies have shown that steam accelerates the decomposition of CaCO3 and shortens the calcination time. However, steam also significantly enhances sulfation in the presence of SO2, and there remains no consensus in the literature regarding the combined effects of steam and SO2 on the decomposition of CaCO3. This study investigates the decomposition characteristics of CaCO3 over time under various reaction atmospheres. The results indicate that while steam accelerates the decomposition of CaCO3, the presence of SO2 almost neutralizes the positive effect of steam. Notably, steam promotes rapid sulfation during the early stages of calcination, which subsequently inhibits the decomposition of CaCO3. Physicochemical characterization reveals that the simultaneous presence of steam and SO2 leads to the rapid formation of CaSO4 on the sorbent surface, with steam-induced pore expansion further enhancing sulfation in the internal pores of the grains. Additionally, this study elucidates the mechanism by which steam accelerates CaCO3 decomposition. It was found that the presence of steam increases the adsorption energy of the CaCO3 (1 0–1 4) surface for SO2 and that H2O molecules facilitate a lower activation energy for the formation of HSO3* compared to SO3*. These findings validate the experimental results and provide a deeper understanding of the combined effects of steam and SO2 during the calcination process from a microscopic perspective.

The Effect of the Calcination Time on the Microstructure and Properties of MnZn Ferrite Powders

MnZn ferrite powders were prepared based on the novel nano in situ composite method and through chemical sol-spray drying–calcination technology. The precursor powders were calcined at 1060 °C at different calcination times (1–9 h) to research the influences of the calcination time on MnZn ferrite powders. The research results revealed that all samples had similar morphologies composed of fine particles. The pure MnZn ferrite spinel phase can only be obtained when the calcination time does not exceed 3 h. Otherwise, some α-Fe2O3 or γ-Fe2O3 impurities will appear. The particle size descended with an increasing calcination time and then ascended. After 3 h of preservation, the smallest particle size was obtained, and it exhibited a unimodal distribution. The saturation magnetization (Ms) increased at first and decreased later with an increasing calcination time, and the optimal value (53.4 emu/g) was reached after holding for 3 h. In view of this work, the optimal calcination time is 3 h.

Precisely designed 3-stage calcination strategy for lithium-rich manganese-based cathodes with improved cycling performance

The poor cycling performance of Li-rich manganese-based (LMR) cathodes is one of the challenges that need to be urgently overcome. Enhancing the stability of the layered structure responsible for lithium-ion diffusion is an effective way to improve the cycling performance. Layered structures are mainly formed during the high-temperature solid-phase reaction, whereas the prolonged and constant-high-temperature calcination conditions in conventional calcination procedure may pose a threat to the layered structural stability. Thus, in order to optimize the formation environment of layered structures under high-temperature solid-phase reaction, we have designed suitable temperature-controlled strategies for each stage of layered structure formation, gradual maturation, and post-treatment, respectively, referred to as the 3-stage calcination strategy. This calcination strategy contributes to the formation of a more ordered and stable layered structure, which significantly improves the cycling performance of LMR cathodes (capacity retention rate of 85.2 % after 200 cycles at 1C). The shortening of the constant high temperature calcination time helps to further reduce the production cost of the batteries. The design concept of this work is to regulate the formation process of layered structures in stages, which provides inspiration for the efficient and controllable synthesis of electrode materials with excellent structural stability at low production cost.

Pore structure regulation of nano-CdSnO3 based on particles adhesion and mass transfer for enhanced NO-sensing

CS-x (x = 1, 2, 4, 6) nanoparticles have been successfully prepared by simple hydrothermal method combined with calcination process, and the calcination time is adjusted to optimize micro-structure characterization for their enhanced NO-sensing. The techniques of XRD, Raman, SEM, TEM, TGA, DSC, BET, and XPS are used to study their phase structure, micro-morphology, thermal decomposition process and surface states, then the possible gas-sensitive mechanism is analyzed. Results show that the typical CS-2 sensor has the maximum response of 130–50 ppm NO at 90 ℃, the short response/recovery time of 40/45 s, and the low detection limit of 0.1 ppm (1.18). It also has the reliable NO selectivity against to other interfering gases, good repeatability and high stability. Its enhanced NO-sensing performance may be due to the optimization of pore structure by adjusting the calcination process based on particles adhesion and mass transfer, which increases the pore size and specific surface area that could provide the channel and active sites for gas diffusion and adsorption, thus further promoting the gas-sensing reaction. The experimental methods and ideas of pore structure regulation provide a new way for the design of high-performance sensitive materials.

Effects of Over-Sintering on Cyclic Calcination and Carbonization of Natural Limestone for CO2 Capture

To know the sustainable performance of calcium-based adsorbents is one of the important aspects to realize efficient and economical carbon capture, and to systematically study the properties of natural adsorbents is conducive to their industrialization. The cyclic calcination and carbonation characteristics of a typical natural limestone were investigated using a thermal gravimetric analyzer. Two kinds of over-sintering conditions were selected to emphatically study the cyclic separation of CO2 from limestones through prolonging the calcination time and increasing the calcination temperature. The results showed that the untimely end of the chemical reaction control stage caused by excessive sintering is the direct reason for the reduction in cyclic carbonation conversion, and the changes in surface morphology of calcined products due to pore collapse and fusion are the fundamental reasons for the reduction in cyclic carbonation conversion. The excessive sintering caused by extending the calcining time or increasing the calcining temperature has great inhibition on this cycle only; the inhibition decreases rapidly in subsequent cycles. In addition, SEM and BET–BJH tests further confirm the influence of the over-sintering phenomenon. With the further increase in cycle number, the early excessive sintering has certain stimulative effects on the subsequent carbonation reaction. It is expected to provide a reference for the subsequent research and development of natural calcium-based adsorbents.

Lithium salt preprocessing calcination strategy for a more stable layered structure of lithium-rich manganese-based cathodes

The poor cycling performance of lithium-rich manganese-based (LMR) cathodes limits their practical applications. The stability of the layered structure is closely related to the cycling performance. The high-temperature solid-state reaction between transition metal oxides (TMOs) and lithium salts promotes the formation of the layered structure, which determines the quality of the layered structure. Considering the influence of physicochemical changes of the lithium salt on the formed layered structural stability, in this work, the calcination strategy includes a short period of holding time near the melting point of Li2CO3, referred to as the lithium salt preprocessing calcination strategy, which allows the molten Li2CO3 to be fully contacted with TMOs at relatively low temperatures, alleviating the problem of Li in the thermal decomposition products of Li2CO3 not easily further reacting with TMOs. Compared to the conventional calcination procedure, this new calcination strategy reduces the oxygen vacancy concentration as well as the relative Mn3+ content on the surface of the cathodes, which significantly improves the cycling performance. In addition, the shortening of the constant high temperature calcination time effectively reduces the production energy consumption, which provides a reference for the future efficient and low-cost synthesis of electrode materials with excellent cycling performance.

Molecular Crystal Structure Simulations and Structure-Magnetic Properties of LiFePO4 Composite Particles Optimized by La.

In this study LiFePO4/C composite particles were synthesized using five different carbon sources via a one-step sol-gel method. La-doped LiFePO4 was also synthesized using the sol-gel method. The XRD pattern of LixLayFePO4 (x = 0.9~1.0, y = 0~0.1) after being calcined at 700 °C for 10 h indicates that as the doping ratio increased, the sample's cell volume first increased then decreased, reaching a maximum value of 293.36 Å3 (x = 0.94, y = 0.06). The XRD patterns of Li0.92La0.08FePO4 after being calcined at different temperatures for 10 h indicate that with increasing calcination temperature, the (311) diffraction peak drifted toward a smaller diffraction angle. Similarly, the XRD patterns of Li0.92La0.08FePO4 after being calcined at 700 °C for different durations indicate that with increasing calcination times, the (311) diffraction peak drifted toward a larger diffraction angle. The infrared spectrum pattern of LixLayFePO4 (x = 0.9~1.0, y = 0~0.1) after being calcined at 700 °C for 10 h shows absorption peaks corresponding to the vibrations of the Li-O bond and PO43- group. An SEM analysis of LixLayFePO4 (x = 1, y = 0; x = 0.96, y = 0.04; x = 0.92, y = 0.08) after being calcined at 700 °C for 10 h indicates that the particles were irregular in shape and of uniform size. The hysteresis loops of Li0.92La0.08FePO4 after being calcined at 600 °C, 700 °C, or 800 °C for 10 h indicate that with increasing calcination temperature, the Ms gradually increased, while the Mr and Hc decreased, with minimum values of 0.08 emu/g and 58.21 Oe, respectively. The Mössbauer spectra of LixLayFePO4 (x = 1, y = 0; x = 0.96, y = 0.04; x = 0.92, y = 0.08) after being calcined at 700 °C for 10 h indicate that all samples contained Doublet(1) and Doublet(2) peaks, dominated by Fe2+ compounds. The proportions of Fe2+ were 85.5% (x = 1, y = 0), 89.9% (x = 0.96, y = 0.04), and 96.0% (x = 0.92, y = 0.08). The maximum IS and QS of Doublet(1) for the three samples were 1.224 mm/s and 2.956 mm/s, respectively.

Utilization of Sintered Sludge Ash with Different Mechanical-Thermal Activation Parameters as a Supplementary Cementitious Material: Mechanical Properties and Life Cycle Assessment of Cement-Based Paste.

The proposal of sintered sludge cement (SSC) paste aligns with the low-carbon development goals of building materials. However, there is a lack of scientific guidance for the preparation of sintered sludge ash (SSA). Herein, this study systematically investigates the influence mechanism of mechanical-thermal activation parameters of SSA on the mechanical properties and life cycle assessment (LCA) of SSC paste, and conducts a comprehensive evaluation using a radar chart and the TOPSIS method. The results show that with the increase in calcination temperature and duration, the compressive and flexural strengths of the SSC paste are improved, especially at 600 °C and above, increasing by 57.92% and 62.52%, respectively. The longer calcination time at 1000 °C results in a decrease in its mechanical properties. The addition of SSA significantly reduces the LCA indicators of cement paste. Specifically, 30% SSA only contributes 8.1% to the global warming potential. Compared to calcination, the LCA indicators have less sensitivity to ball milling, and prolonging the time hardly increases them. Based on performance and environmental impact, the optimal SSA is obtained by calcining at 800 °C for 2 h and ball milling for 10 min. This study can provide theoretical guidance for efficient building material utilization of dredged sludge.

Size-controlled synthesis of cobalt phosphide (Co2P) nanoparticles and their application in non-enzymatic glucose sensors via a carbon fiber/Co2P composite

In this study, we synthesized Co2P nanoparticles using a solid-state phosphorization method and evaluated the electrocatalytic response to glucose oxidation reaction (GORs). The influence of synthesis conditions on the particle size, morphology of Co2P species and formation of byproducts is discussed. A lower molar ratio of the phosphorus precursor leads to a decrease in the generation of byproducts. In addition, the calcination temperature and time greatly influence the purity level of the Co2P species and its particle size. Thus, we obtained three pure Co2P nanoparticles with different sizes and morphologies. Significant differences in their electrocatalytic activity against the GOR are observed depending on the size of the particles, being the smaller ones the most efficient. Based on Tafel analysis, a higher catalytic activity was observed for the carbon fibre (CF)/Co2P composite compared to Co2P, which presented a greater onset potential and low response in current density. Tafel slopes close to 120 mV/dec were obtained for both materials, indicating that the mechanism is independent of the type of Co2P-based material used. Finally, the performance of the GCE/CF/Co2P sensor was demonstrated by amperometric measurements, with a sensitivity of 409 µAmM-1cm-2, a linear range between 39.4 µM and 150 µM, and a detection limit of 0.97 µM, analytical characteristics better than those obtained for other cobalt phosphide-based sensors reported in the literature. In addition, the GCE/CF/Co2P sensor shows excellent selectivity and demonstrated to be competitive compared to other Co-based non-enzymatic glucose sensors.

Effect of calcination time on modulating the properties of battery type NiMn2O4 intended for supercapacitor applications

In this study, the synthesis of nanostructured NiMn2O4 is achieved through the novel wet-chemical reduction synthesis method, maintained at a constant temperature of 500 °C. Variations in calcination time to 4, 5, and 6 h, with a constant synthesis temperature, result in the formation of NiMn2O4 (NMO) nanostructures (NSs). These NMO-NSs are employed as electroactive materials in the assembly of electrochemical supercapacitors. Electrodes, composed of NMO-NSs calcined for 4 h, at constant temperature of 500 °C, are observed to exhibit a high specific capacitance/capacity of 966.7 F g−1 (579 C g−1) respectively, at a scan rate of 5 mV s−1. Retention of 96 % of the specific capacitance is noted after 5000 cycles of the as optimum electrode (NM-4 h). The significant influence of calcination time on the efficiency of electrochemical supercapacitors is highlighted in this research. An asymmetric supercapacitor device (ASSCs), featuring a wide working potential window of 0–1.6 V and a energy density of 38.9 W h kg−1 at a power density of 5 kW kg−1. As fabricated ASSCs demonstrates high specific capacitance of 109.4 F g−1/175 C g−1 with capacitance retention of 79.9 % over 5000 cycles. The potential of highly porous binary NiMn2O4 NSs as suitable materials for high-performance supercapacitor devices is suggested by the findings.

Parametric Study of Vanadium Extraction Process from Refining Tailings of Crude Titanium Tetrachloride

The recovery of vanadium from titanium tetrachloride tail residue is a resource-efficient and environment-friendly method for treating hazardous vanadium-containing solid waste. In this study, to maximize the recovery rate of vanadium in the vanadium extraction process, the independent calcination and leaching factors were optimized using response surface methodology, in terms of calcination temperature (750–950 °C), calcination time (60–180 min), leaching liquid–solid ratio (5–25 mL/g), and leaching time (30–150 min). The results revealed that the calcination temperature was the most effective parameter for vanadium recovery, while the liquid–solid ratio was the least effective factor. Additionally, the optimal conditions were identified as a calcination temperature of 937 °C, a calcination time of 150 min, a leaching solid-to-liquid ratio of 17.4 mL/g, and a leaching time of 150 min. The maximum predicted recovery rate of vanadium by the model regression equation reached 93.1% and showed high credibility consistent with the experimental recovery rate of 93%.

Electrical and microstructural characteristics of GDC electrolyte synthesised by benzoate coprecipitation for solid oxide fuel cells

Gadolinium-doped ceria (GDC) is a promising electrolyte material for developing solid oxide fuel cells (SOFCs) because it offers a higher ionic conductivity at the intermediate operating temperature. In this work, nanocrystalline GDC (Ce1-xGdxO2-x/2, where x = 0.1 and 0.2) powders were synthesised through a novel co-precipitation synthesis method (benzoate route) using ammonium benzoate as a low-cost precipitant. The effect of the synthesis route and processing variables (calcination temperatures and time) on the microstructural and electrical properties of the resulting GDC powder was studied systematically. Multiple GDC electrolyte pellets were fabricated by pressing the GDC powders, followed by sintering the samples at 1100 °C for 6 h. The ionic and electronic conductivity of the GDC pellets were measured in air using EIS at different temperatures (450–750 °C). Huggins' model was used to determine the ionic and electronic conductivity of the GDC pellets. The fabricated electrolyte pellets showed a high relative density of 98.31and 99.02 % for the pre-calcined non-washed and pre-calcined washed powders, respectively, with a crystal size lower than 12 nm. Among all samples, the GDC electrolyte pellet fabricated using the pre-calcined washed powder exhibited the highest ionic conductivity of 3.63E-01 S cm−1 at 750 °C and activation energy of 0.52 eV with an average crystal size of 7–8 nm. The results of this study help to understand and design more efficient ceramic fuel cells with controlled microstructure and compositions at a lower cost.