Search Results (555)

In the current industry standard of batch processing electrode slurry, manual cleaning processes pose significant challenges due to their labor intensive nature. The long-term objective is to expand the existing mixing process to create an intelligent, autonomous, and continuous slurry production process. This will result in a reduction in downtime and setup times, as well as an increase in the degree of automation. Additionally, the implementation of complex parameter selection in the mixing process is intended to make it manageable for variable recipes, ensuring efficient, resource-saving process control. This study aims to address this issue by investigating the continuous production of anode slurry and its subsequent cleaning in a laboratory extruder, with a focus on optimizing the cleaning conditions and analyzing the residual slurry. Several samples were taken during the cleaning of the process area and analyzed by UV-Vis spectroscopy, while also quantifying the residual slurry on the screw elements. The effectiveness of the cleaning was evaluated using Sinner’s Circle parameters, i.e., the effects of time, mechanical, chemical and thermal treatment on the effectiveness of the cleaning process are evaluated and discussed. Several detergents were tested, including deionized water, alcohol, and industrial detergents. Deionized water proved to be the most effective in terms of cleaning rate and residual slurry. In addition, higher screw speeds and flow rates improved cleaning efficiency. The effect of temperature was significant, with better cleaning rate results at higher temperatures. This indicates that mechanical and thermal factors play a critical role in improving cleaning kinetics. For a more in-depth knowledge of the resulting cell chemistry, successive cross-contamination of cathode materials in anode half-cells was examined. As a result, an indicator was identified in the first cycle that displays a voltage increase during delithiation with regard to electrochemical properties. Full article

The growing demand for lithium-ion batteries (LIBs) is driving a rapid increase in the volume of spent cells which—as hazardous waste—must be managed effectively in accordance with circular-economy principles. Hydrometallurgical recycling allows the recovery of critical metals at far lower environmental cost than primary mining. This paper presents a method for obtaining metallic nickel from sulfate leach solutions produced by leaching the so-called “black mass” derived from shredded LIBs. Nickel electrodeposition was performed on a stainless-steel cathode with Ti/Ru-Ir anodes at 60 °C and pH 3.0–4.5. Two process variants were examined. Variant A—with a decreasing Ni²⁺ concentration (49 → 25 g L⁻¹)—achieved a current efficiency of 60–88%, but the deposits were non-uniform and prone to flaking. Variant B—in which the bath was stabilized by the continuous dissolution of Ni(OH)₂ (maintaining Ni²⁺ at 35–40 g L⁻¹) and amended with PEG-4000, H₃BO₃ and Na₂SO₄—reached higher efficiency (78–93%) and produced uniform, bright deposits up to 0.5 mm thick with a purity >90%. The results confirm that keeping the nickel concentration constant and appropriately modifying the electrolyte significantly improve both the qualitative and economic aspects of recovery, highlighting electrolysis as an efficient way to process LIB waste and close the nickel stream within the material cycle. Full article

The electrochemical production of silicon from SiO₂ in molten salts can reduce energy consumption and mitigate carbon emissions associated with the conventional carbothermic process. In this study, we compare the anodic behaviour of platinum, graphite, and tin oxide electrodes in molten CaCl₂-NaCl-CaO-SiO₂ at 850 °C using electrochemical methods including cyclic voltammetry, linear sweep voltammetry, and chronoamperometry. Pt exhibited low oxygen evolution overpotentials and no significant currents before OER, compared to SnO₂. An eight-hour potentiostatic electrolysis with a SnO₂ anode and a graphite cathode yielded a Si-Sn deposit, indicating partial dissolution of the SnO₂ anode during the electrolysis process. These results highlight the kinetic trade-off of SnO₂ relative to Pt, and the risk of Sn contamination with extended electrolysis times. While SnO₂ is unsuitable for production of high-purity Si, it remains a promising anode candidate for Si-Sn alloy formation. Full article

Elevated levels of total ammonia nitrogen (TAN) are recognized as a primary contributor to acute toxicity in aquatic organisms across freshwater aquaculture and mariculture environments. Existing technologies for TAN removal from wastewater are constrained by complex processes, high energy consumption, and an inability to meet discharge standards in a single step. Conventional electrochemical routes often over-oxidize TAN to nitrate, which undermines the goal of achieving truly harmless wastewater. Herein, we use a three-dimensional (3D) electrochemical system packed with particulate electrodes to realize the “TAN to N₂” in one step. The design exploits a synergistic mechanism in which anodic ·OH and HClO cooperatively oxidize TAN while cathodic sites concurrently reduce nitrate nitrogen, turning NH₄⁺ directly to N₂ without nitrate accumulation. The 3D electrochemical system is particularly suitable for marine aquaculture wastewater, especially when addressing the low TAN concentration characteristic. Results show that the 3D system increased N₂ selectivity from 67.90% to 92.06% while stabilizing wastewater pH within a mildly alkaline window. The system operates in situ, enabling direct recycle of culture water and offering a new technological paradigm for harmless, on-site treatment and resource recovery from mariculture wastewater. Full article

Electrolysis and biological processes, such as fermentation and microbial electrolysis cells, offer efficient hydrogen production alongside wastewater treatment. This study presents a novel microbial electrolyzer (ME) comprising a titanium dioxide (TiO₂) anode, a nickel–iron–carbon (NiFeC) cathode, and a cellulose nanocrystal proton exchange membrane (CNC-PEM) designed to generate hydrogen from palm oil mill effluent (POME). The system is powered by a 12 V electric double-layer organic supercapacitor (EDLOSC) integrated with a ZnO/PVA-based solar thin film. Power delivery to the TiO₂-NiFeC-PEM electrolyzer is optimized using an Adaptive Neuro-Fuzzy Inference System (ANFIS). Laboratory-scale pilot tests demonstrated effective degradation of POME’s organic content, achieving a hydrogen yield of approximately 60%. Additionally, the nano-structured ZnO/CuO–ZnO/PVA solar film facilitated stable power supply, enhancing in situ hydrogen production. These results highlight the potential of the EDLOSC-encased ZnO/PVA-powered electrolyzer as a sustainable solution for hydrogen generation and industrial wastewater treatment. Full article

With the increasing volumes of spent lithium-ion batteries from electric vehicles and the concurrent increase in raw materials cost for cathode production, finding effective methods for recycling battery materials has become critically important. This study investigated a pyrometallurgical approach using microwave irradiation to achieve carbothermal reduction of LiCoO₂. FactSage thermodynamic calculations were performed for process simulation and an infrared thermal camera was employed for temperature measurements, allowing the authors to optimize the process parameters to obtain metallic cobalt. Specifically, the research included microwave experiments on mixed black mass samples of anode and cathode materials in different proportions, treated at varying power levels and exposure times under air atmosphere. The effect of the process parameters and therefore of the temperature on microstructure was studied with SEM-EDS and XRD analysis. The feasibility of a wet magnetic separation method between cobalt and lithium compounds formed during the reaction was also evaluated. The results obtained from the final separation process indicated that individual compounds can be obtained at the end of the cycle; moreover, the optimization of time, temperature, and graphite additions during the tests allowed the authors to obtain promising results. Full article

Hydrogen-rich water (HRW) has attracted significant attention for its physiological and therapeutic potential, driving efforts to develop a green and direct production approach. In particular, if solar energy could be utilized to power the process and the power-generation and water-production modules could be integrated into a single device, it would greatly enhance portability and user convenience, making it an ideal solution for personalized healthcare and outdoor applications. We demonstrate solar-assisted proton exchange membrane (PEM) electrolysis using symmetric IrO₂ electrodes at both cathode and anode to directly generate HRW. The symmetric design simplifies manufacturing, mitigates lifetime mismatch and metal-ion cross-contamination. IrO₂ films were electrodeposited on stainless steel substrates and annealed at 400–700 °C. When coupled with a 100 cm² Si solar cell, the electrode annealed at 550 °C—featuring ~6 nm IrO₂ nanocrystals embedded in an amorphous matrix—exhibited the highest hydrogen production rate. At an applied voltage of 4 V, this 550 °C-annealed IrO₂ electrode produced approximately 1800 μmol h⁻¹ of H₂, corresponding to about 44 mL h⁻¹ of H₂ at 25 °C and 1 atm. Corrosion tests show the HRW is less aggressive to iron than DI, RO, and tap water, suggesting better compatibility with metallic components. During water splitting, the oxidation–reduction potential (ORP) rapidly decreases to <−300 mV within 0–10 min and then stabilizes, with the 550 °C–annealed electrode exhibiting the lowest ORP. Upon air exposure, the ORP increases by ~200 mV over 45–70 min yet remains reductive for >120 min, indicating persistent dissolved H₂ and sustained performance. Overall, the symmetric IrO₂ architecture provides a green, stable, and direct route to HRW production. Full article

The anodization of Ti° enables the formation of well-ordered TiO₂ nanotubes, a highly promising nanomaterial with exceptional photochemical properties and potential applications in the energy and environmental sectors. This study addresses the growth of TiO₂ nanotubes on large-scale surfaces applied for photocatalytic processes. The present investigation approaches the scaling up of the reactor for anodizing Ti°-coated flat surfaces and thus connecting the TiO₂-nano-structure with real-world applications. For this, 316 stainless steel sheets were coated with a uniform Ti° layer using the arc cathodic method. The results indicate that the (~3 µm) thick Ti° arc-PVD coatings are well anodized, despite the inherent amount of µm-sized droplets produced during the deposition. The results reported here highlight the effects of the anodization process parameters—voltage, current, and time—on nanotube growth. At 60 V, the nanotubes exhibited a highly uniform cylindrical morphology, homogeneous walls contributing to an ordered, stable, and open nanostructure at large Ti-coated surfaces. The scaling up of the reactor for the controlled anodization process of Ti° coating is addressed. This approach validates Ti°-based PVD coatings at a semi-industrial scale on commercial stainless steel, thus enabling affordable production costs. Lastly, the anodization of Ti° coatings is a viable, scalable manufacturing process for producing photocatalytic nanostructured surfaces. Full article

Magnesium metal boasts a high theoretical volumetric specific capacity and abundant reserves. Magnesium batteries offer high safety and environmental friendliness. In recent years, magnesium-ion batteries (MIBs) with Mg or Mg alloys as anodes have garnered extensive interest and emerged as promising candidates for next-generation competitive energy storage technologies. However, MIBs are plagued by issues such as sluggish desolvation kinetics and slow migration kinetics, which lead to limitations including a limited electrochemical window and poor magnesium storage reversibility. Herein, the sodium vanadium phosphate @ carbon (Na₃V₂(PO₄)₃@C, hereafter abbreviated as NVP@C) cathode material was synthesized via a sol–gel method. The electrochemical performance and magnesium storage mechanism of NVP@C in a 0.5 M magnesium bis(trifluoromethanesulfonyl)imide/ethylene glycol dimethyl ether (Mg(TFSI)₂/DME) electrolyte were investigated. The as-prepared NVP@C features a pure-phase orthorhombic structure with a porous microspherical morphology. The discharge voltage of NVP@C is 0.75 V vs. activated carbon (AC), corresponding to 3.5 V vs. Mg/Mg²⁺. The magnesium storage process of NVP@C is tentatively proposed to follow a ‘sodium extraction → magnesium intercalation → magnesium deintercalation’ three-step intercalation–deintercalation mechanism, based on the characterization results of ICP-OES, ex situ XRD, and FTIR. No abnormal phases are generated throughout the process, and the lattice parameter variation is below 0.5%. Additionally, the vibration peaks of PO₄ tetrahedrons and VO₆ octahedrons shift reversibly, and the valence state transitions between V³⁺ and V⁴⁺/V⁵⁺ are reversible. These results confirm the excellent reversibility of the material’s structure and chemical environment. At a current density of 50 mA/g, NVP@C delivers a maximum discharge specific capacity of 62 mAh/g, with a capacity retention rate of 66% after 200 cycles. The observed performance degradation is attributed to the gradual densification of the CEI film during cycling, leading to increased Mg²⁺ diffusion resistance. This work offers valuable insights for the development of high-voltage MIB systems. Full article

Computed tomography (CT) imaging has proven to be effective for detecting and visualizing a wide range of inhomogeneities and defects. Applying computer vision (CV)-based image processing enables detailed feature measurements on selected CT image slices, which could be of benefit as cells of the same type often show variations in electrical properties. When combined with electrical testing, CT imaging could provide valuable insights into the battery cell, helping to identify potential sources of electrical deviations. However, it remains unclear to what extent CT-based measurements, especially for larger prismatic cells, e.g., those used in automotive applications, can explain electrical deviations aside from identifying significant or latent defects. Therefore, this study performs a correlative analysis and compares the electrical measurement results with CT-based measurements of the cell’s physical features, specifically the anode and cathode sizes. Electrical and CT measurements from ten lithium iron phosphate/graphite (LFP/C) cells of the same type are analyzed. The results indicate that while CT imaging has the potential to help identify the sources of electrical deviations, it also shows that cell-level CT measurements alone cannot fully explain electrical performance deviations. Measurement uncertainty, the potential overlapping impact of other cell features, and the actual influence of the measured physical properties on the cell’s electrical performance limit the correlation between CT-based measurements and electrical parameters. Full article

The recovery of rare earth elements (REEs) from the spent NdFeB magnets has great strategic significance for ensuring the security of critical mineral resources. This process requires scientifically designed separation technologies to ensure high output and purity of the obtained rare earths. Hydrometallurgy has been widely applied to extract REEs from spent permanent magnets. This paper summarizes and reviews hydrometallurgical technologies, mechanisms, and applications for the separation and recovery of REEs and iron (Fe) from the spent permanent magnets. Key methods include: The hydrochloric acid total solution method, where the spent NdFeB is completely dissolved in hydrochloric acid, iron is precipitated and removed, and then REEs are extracted. The hydrochloric acid preferential dissolution method, where spent NdFeB magnets are first fully oxidized by oxidative roasting, converting Fe²⁺ to Fe³⁺, which hydrolyzes to Fe(OH)₃, and is precipitated and removed, allowing for the subsequent extraction of REEs to obtain rare earth oxides. Acid baking and water leaching, where spent NdFeB is calcined with acidification reagents, and the calcined products are dissolved in water to leach out REEs. At the same time, Fe is retained in the leaching residue. Electrolysis in aqueous solution, where Fe is electrolyzed at the anode or deposited at the cathode to separate it from REES. Organic acids leaching, where organic acids dissolve metals through acidolysis and complexation. Bioleaching, which utilizes microorganisms to recover metal through biological oxidation and complexation. Ionic liquid systems, where Fe or REEs are extracted using ionic liquid or leached by deep eutectic solvents. This paper provides an in-depth discussion on the challenges, advantages, and disadvantages of these strategies for recycling spent NdFeB magnets, as well as the leaching and extraction behavior of REEs. It focuses on environmental impact assessment, improving recovery efficiency, and decreasing reagent consumption. The future development direction for recycling spent NdFeB magnets is proposed, and a research idea of proposing a combined process to avoid the drawbacks of a single recycling method is introduced. Full article

Fiber-based and fabric batteries signify a groundbreaking development in energy storage, allowing for the straightforward incorporation of power sources into wearable fabrics, intelligent apparel, and adaptable electronics. In this study, we introduce a novel strategy for one-step fabrication of a flexible lithium titanate oxide (Li₄Ti₅O₁₂, LTO) anode directly on a copper current collector via electrospinning, eliminating the need for high-temperature post-processing. Based on our previous work with electrospun nanofiber cathodes and carbon-based current collector, we prepared the LTO electrode using polyethylene oxide (PEO) as a binder and carbon additives to enhance mechanical integrity and conductivity. LTO fiber mats detached from the current collector were found to endure multiple instances of bending, twisting, and folding without any structural damage. LTO/Li cells incorporating electrospun fiber LTO electrodes with 72 wt% active material loading deliver a high capacity of 170 mAh g⁻¹ at 0.05 C. In addition, they demonstrate excellent cycling stability with a capacity loss of only 0.01% per cycle over 200 cycles and maintain a capacity of 160 mAh g⁻¹ at 0.1 C. The scalability of the heat-treatment-free method for fabricating flexible LTO anodes, together with the improved mechanical durability and electrochemical performance, offers a promising route toward the development of next-generation flexible and wearable energy storage devices. Full article

Hydrometallurgy is currently the mainstream industrial process for recovering valuable components (nickel, cobalt, manganese, lithium, etc.) from spent ternary lithium-ion battery cathode materials. During the crushing of lithium batteries, cathode materials, anode materials (graphite), and electrolytes become mixed. Consequently, fluoride ions inevitably enter the leaching solution during the hydrometallurgical recycling process, with concentrations as high as 100–300 mg/L. These fluoride ions not only adversely affect the quality of the recovered precursor products but also pose environmental risks. To address this issue, this study employs a synthesized lanthanum–zirconium (La@Zr) composite material, with a specific surface area of 67.41 m²/g and a pore size of 2–50 nm, which can reduce the fluoride ion concentration in the leaching solution to below 5 mg/L, significantly lower than the 20 mg/L or higher that is typically achieved with traditional calcium salt defluorination processes, without introducing new impurities. Under optimal adsorption conditions, the lanthanum–zirconium adsorbent exhibits a fluoride ion adsorption capacity of 193.4 mg/g in the leaching solution, surpassing that of many existing metal-based adsorbents. At the same time as the valuable metals, Li, Ni, and Co, are basically not adsorbed, the selective adsorption of fluoride ions can be achieved. Adsorption isotherm studies indicate that the adsorption process follows the Langmuir model, suggesting monolayer adsorption. The secondary adsorption process is primarily governed by chemical adsorption, and elevated temperatures facilitate the removal of fluoride ions. Kinetic studies demonstrate that the adsorption process is well described by the pseudo-second-order model. After desorption and regeneration with NaOH solution, the adsorbent still has a favorable fluoride removal performance, and the adsorption rate of fluoride ions can still reach 95% after four cycles of use. With its high capacity, rapid kinetics, and excellent selectivity, the adsorbent is highly promising for large-scale implementation. Full article

Brass components are widely used in heat dissipation and thermal emission devices due to their high thermal conductivity and ease of processing. However, these applications demand good thermal oxidation resistance, high emissivity, and excellent corrosion resistance. In this study, nickel coatings were deposited on brass substrates by direct current electroplating, and the effects of current density and cathode configuration on the microstructure, emissivity, and corrosion resistance of the coatings were systematically investigated. The results show that the emissivity of the coatings first increased and then decreased with increasing current density. Optimal performance was achieved when the cathode and anode were positioned perpendicular to the horizontal plane at a current density of 3.0 A·dm⁻². Under these conditions, the coatings exhibited a smooth, uniform, and dense microstructure, with evenly distributed metallic grains. Electrochemical polarization and impedance measurements further confirmed the superior corrosion resistance of this coating, with a minimum corrosion current density of 0.259 μA·cm⁻², a maximum polarization resistance of 6381.55 Ω·cm², and a minimum corrosion rate of 0.023 mm/a. These findings demonstrate a simple and effective approach to enhancing both the emissivity and corrosion resistance of brass substrates, offering practical value for thermal management applications. Full article

Novel high-energy, binder-free, and solvent-free carbon–silicon layered composite anodes were manufactured using an industrially scalable Virtual Cathode Deposition (VCD) technique. The deposition process transforms commercial graphite target material into carbon polymorph (CALIB) layers, interposed with silicon layers deposited in situ from a silicon source, thereby forming high-capacity anodes for Li ion batteries. Composite CALIB-C/Si₄ anodes with a layered architecture exhibited a first-cycle specific capacity of over 1550 mAh g⁻¹ at 0.1 A g⁻¹ and retained a capacity of ~1080 mAh g⁻¹ at a 1 A g⁻¹ rate after 200 cycles. Detailed structural characterisation revealed a disordered carbon matrix encompassing nanosized sp²-bonded carbon clusters (average size ~20 nm), cross-linked by a network of sp³-bonded atomic sites, with predominant mesoporosity and high surface area. The silicon layers were found to consist of an amorphous Si matrix with embedded nanocrystalline components, emulating the growth mode of the CALIB buffer. The presence of the mesoporous carbon matrix accommodated the stress caused by the alloying/de-alloying of silicon nanolayers, thereby alleviating the pulverisation effect and preserving the structural integrity of the composite. The initial performance and capacity decay of the anodes were found to depend on the thickness of the CALIB-C buffer interlayers. Full article