High dielectric barium titanate porous scaffold for efficient Li metal cycling in anode-free cells

Li metal batteries are being intensively investigated as a means to achieve higher energy density when compared with standard Li-ion batteries. However, the formation of dendritic and mossy Li metal microstructures at the negative electrode during stripping/plating cycles causes electrolyte decomposition and the formation of electronically disconnected Li metal particles. Here we investigate the use of a Cu current collector coated with a high dielectric BaTiO3 porous scaffold to suppress the electrical field gradients that cause morphological inhomogeneities during Li metal stripping/plating. Applying operando solid-state nuclear magnetic resonance measurements, we demonstrate that the high dielectric BaTiO3 porous scaffold promotes dense Li deposition, improves the average plating/stripping efficiency and extends the cycling life of the cell compared to both bare Cu and to a low dielectric scaffold material (i.e., Al2O3). We report electrochemical tests in full anode-free coin cells using a LiNi0.8Co0.1Mn0.1O2-based positive electrode and a LiPF6-based electrolyte to demonstrate the cycling efficiency of the BaTiO3-coated Cu electrode.

Roles and Principles of Sterilisation Process in Palm Oil Mills

Sterilisation in palm oil mills is considered a pre-treatment process as it affects stripping efficiency and oil quality. Although sterilisation technology has been well-established in the palm oil milling industry, the roles and principles of sterilisation, particularly related to the chemical changes in fruits and stalks occurring during the process, have been rarely reported. The review begins with the background literature on the biochemical properties of the FFBs, such as the compositions of binding carbohydrates and the phenomena of natural fruit detachment. Followed by the harvesting practice to understand the type of FFBs supplied to the industry. In addition, a comparison of the well-established conventional and alternative sterilisation technologies and sterilisation functions is critically reviewed and assessed. Establishing the current sterilisation process initiatives to address the natural fruit’s separation more efficiently in palm oil mills is important. Particularly visualise sterilisation as a breakup of specific binding carbohydrates that leads to strippability. It will provide a further understanding of the sterilisation mechanism, which would benefit the palm oil miller in optimising the processing of fresh fruit bunches. The information provided in this review is necessary to mitigate the percentage of unstripped bunches and reduce the oil losses and ultimately enhance the oil extraction rate.

Extraction of Cu(II), Fe(III), Zn(II), and Mn(II) from Aqueous Solutions with Ionic Liquid R4NCy

The leaching of copper ores produces a rich solution with metal interferences. In this context, Fe(III), Zn(II), and Mn(II) are three metals contained in industrial copper-rich solutions in high quantities and eventually can be co-extracted with the copper. The purpose of the current study was to determine the feasibly of solvent extraction with the use of ionic liquid methyltrioctyl/decylammonium bis (2,4,4-trimethylpentyl)phosphinate (R4NCy) as an extractant of Cu(II) in the presence of Fe(III), Zn(II), and Mn(II). In general terms, the results showed a high single extraction efficiency of all the metals under study. In the case of Fe(III) and Zn(II), the extraction was close to 100%. On the contrary, the stripping efficiency was poor to Fe(III) and discrete to Zn(II), but very high to Cu(II) and Mn(II). Finally, the findings of this study suggest that the ionic liquid R4NCy is feasible for the pre-treatment of the copper solvent extraction process to remove metal impurities such as Fe(III) and Zn(II).

Purification of recovered phosphoric acid by extracting aluminium with di-2-ethylhexyl phosphoric acid

The extraction of aluminium from dilute phosphoric acid with di-2-ethylhexyl phosphoric acid (DEHPA) was optimized using response surface methodology. The optimization was based on the experimental three-level central composite face-centred design (CCF) and was conducted on real-life samples. The three variables included were pH, extractant concentration and aqueous to organic phase ratio (AO). Under the optimized conditions (pH 2.5, 0.6 M DEHPA and AO ratio 1:2), extraction efficiency of 99% for aluminium in four extraction stages is achieved. The purified phosphoric acid solution can then be utilized by the fertilizing industry. Stripping tests for organic phase loaded with aluminium were conducted with sulphuric acid. Extremely high stripping efficiency was obtained with 0.9 M sulphuric acid resulting in the recovery rate of 88% in one stage. After stripping, the aluminium sulphate solution can be reused as a precipitation agent for phosphorus in the wastewater treatment process.

Improving stripping efficiency of double curvature surface on a setup with turret head

The study was performed to develop a method for selecting a rational profile of a profiled flap wheel for a turret stripping head for cleaning parts with different radius of the transverse curvature. Researchers from the Irkutsk National Research Technical University and Irkutsk Aviation Plant designed and fabricated a special PFS-4 (peen forming setup) unit to implement manufacturing technology of large-scale contour-forming components. The unit is equipped with a CNC system, two movable operating elements, a shot blaster and a turret stripping head with four flap wheels. The paper offers methods and criteria for selecting the profiled flap wheel for stripping the contour-forming surfaces of the components, depending on the curvature radius of the latter. A flap wheel with an optimal curvature radius of 40 m was chosen for analysis, which allows a sufficiently large range of profile curvature of the processed components (from 8 to 40 m) to be covered. Profiled flap wheels 100 and 200 m wide with a flap profile radius of 40 m provided uniform material removal when cleaning the surface with a curvature radius from 8 to 40 m without further overlapping with a finished strip. It was shown that wider profiled flap wheels are necessary to increase stripping efficiency. In this case, a 300 mm wide flap wheel can be used for a component surface area with a transverse curvature radius over 14 m and a 400 mm wheel for surface areas with a curvature radius of over 20 m. Thus, comparing the stripping process of a curved surface by the straight flap wheel revealed that profiled flap wheels significantly expand the workability of the PFS-4 unit turret stripping head.

Recovery of Palladium(II) and Platinum(IV) in Novel Extraction Systems

Recovery of platinum group metals (PGM) from complex aqueous solutions generated as a result of leaching of various spent materials (e.g., spent automotive converters) is a vital issue in the context of the circular economy. In this study pyridinium derivatives containing an imidoamide or imine moiety (i.e., 3-[1-(2-ethylhexyloxyimine)methane]-1-propylpyridinium chloride, 3-[1-(decyloxyimine)methane]-1-propylpyridinium chloride, 3-[1-(decyloxyimine)ethane]-1-propylpyridinium chloride and 4-[1-amine(2-ethylhexyloxyimine)]-1-propylpyridinium chloride) are proposed as novel extractants for recovery of palladium(II) and platinum(IV) from model chloride aqueous solutions. The results of liquid-liquid extraction from one-component solutions of palladium(II) or platinum(IV) showed that quaternary pyridinium salts can be used as effective extractants for platinum metal ions. Moreover, PGM extraction from a two-component mixture proved no evident selectivity in the transfer of one of the metal ions to the organic phase. As the best extractant among the investigated ones, D3EI-PrCl (with straight alkyl chain at substituent) can be pointed out, however, problems with effective stripping or phase disengagement after stripping should be indicated as a drawback of the organic phases used. Further investigation should focus on the improvement of the organic phase properties (e.g., increase in hydrophobicity of the extractants and addition of an organic phase modifier) towards stripping efficiency.

Environmental and Economic Sustainability of Swine Wastewater Treatments Using Ammonia Stripping and Anaerobic Digestion: A Short Review

One of the most promising systems to treat swine wastewater is air stripping. This system simultaneously recovers nitrogen salts, to be used as fertiliser, and reduces the organic pollutant load in the effluents of swine breeding farms. Several reviews have discussed the air stripping as a treatment for many types of industrial wastewater or nitrogen-rich digestate (the liquid effluent derived from the anaerobic digestion plants) for the stripping/recovery of nutrients. However, reviews about the use of air stripping as treatment for raw or anaerobically digested swine wastewater are not available in literature. To fill this gap, this study: (i) Summarises the experiences of air stripping for recovery of ammonium salts from both raw and digested swine wastewater; and (ii) compares air stripping efficiency under different operational conditions. Moreover, combined systems including air stripping (such as struvite crystallisation, chemical precipitation, microwave radiation) have been compared. These comparisons have shown that air stripping of raw and digested swine wastewater fits well the concept of bio-refinery, because this system allows the sustainable management of the piggery effluent by extracting value-added compounds, by-products, and/or energy from wastewater. On the other hand, air stripping of raw and digested swine wastewater has not been extensively studied and more investigations should be carried out.

Quantification of Inactive Lithium and Solid Electrolyte Interphase (SEI) Species on Graphite Electrodes After Fast Charging

<p>Rapid charging of Li-ion batteries is limited by lithium plating on graphite anodes, whereby Li⁺ ions are reduced to Li metal on the graphite particle surface instead of inserting between graphitic layers. Plated Li metal not only poses a safety risk due to dendrite formation, but also contributes to capacity loss due to the low reversibility of the Li plating/stripping process. Understanding when Li plating occurs and how much Li has plated is therefore vital to remedying these issues. We demonstrate a titration technique with a minimum detection limit of 20 nmol (5×10^-4 mAh) Li which is used to quantify inactive Li that remains on the graphite electrode after fast charging. Additionally, the titration is extended to quantify the total amount of solid carbonate species and lithium acetylide (Li₂C₂) within the solid electrolyte interphase (SEI). Finally, electrochemical modeling is combined with experimental data to determine the Li plating exchange current density (10 A/m²) and stripping efficiency (65%) of plated Li metal on graphite. These techniques provide a highly accurate measure of Li plating onset and quantitative insight into graphite SEI evolution during fast charge.</p>

Quantification of Inactive Lithium and Solid Electrolyte Interphase (SEI) Species on Graphite Electrodes After Fast Charging

<p>Rapid charging of Li-ion batteries is limited by lithium plating on graphite anodes, whereby Li⁺ ions are reduced to Li metal on the graphite particle surface instead of inserting between graphitic layers. Plated Li metal not only poses a safety risk due to dendrite formation, but also contributes to capacity loss due to the low reversibility of the Li plating/stripping process. Understanding when Li plating occurs and how much Li has plated is therefore vital to remedying these issues. We demonstrate a titration technique with a minimum detection limit of 20 nmol (5×10^-4 mAh) Li which is used to quantify inactive Li that remains on the graphite electrode after fast charging. Additionally, the titration is extended to quantify the total amount of solid carbonate species and lithium acetylide (Li₂C₂) within the solid electrolyte interphase (SEI). Finally, electrochemical modeling is combined with experimental data to determine the Li plating exchange current density (10 A/m²) and stripping efficiency (65%) of plated Li metal on graphite. These techniques provide a highly accurate measure of Li plating onset and quantitative insight into graphite SEI evolution during fast charge.</p>