Precursor Particles Research Articles

Potential one-pot synthesis of spherical magnesium silicate powder by mechanical milling

Synthetic magnesium silicate finds applications in adsorbents, catalysis, pharmaceuticals, foods, cosmetics, and in oil industry. This study introduces a method for potential one-pot preparation of narrowly sized, spherical magnesium silicate powders. After initial synthesis by precipitation from magnesium sulphate and sodium metasilicate solutions, the magnesium silicate precursor was ball-milled with two immiscible liquids, forming a particle-loaded emulsion. Hexane formed the continuous phase; the droplet phase was formed by either acetonitrile, methanol, or water-methanol mixtures. Suspended precursor particles were refined, their fragments became trapped in the droplets, where they were eventually compacted into composite spheres. Prepared spherical powders were characterized using scanning electron microscopy, nitrogen sorption, and low angle laser light scattering. The synthesized powders exhibited narrow size distributions with modes from 3.3 to 92 μm. The spherical powders showed an enhanced flowability and had specific surface areas comparable to or higher than the precipitated precursor powders.

Microstructure and mechanical properties of pitch based mixture modified by additions of graphene oxide precursor and TiB2 particles

Pitch based mixture as binder material is crucial component for structure stability and mechanical properties of carbon/graphite electrodes. In this work, coal tar pitch (CTP) mixture was modified by additions of graphene oxide (GO) precursor and fine TiB2 particles. It is found that 1 wt.%GO addition increases the crystallite size, La value and reduce the defects density of (002) planes in CTP mesophase and carbonization products with increased elastic modulus. The additions of 3 or 5 wt.%TiB2 increase the stacking height of (002) planes (Lc) of CTP pyrolysis and carbonization products with increased edge dislocation density and ultimate strain. The combined additions of TiB2 and GO generate a synergistic effect on further improving the mechanical properties of CTP carbonization products with increasing the stacking order of (002) plane, crystallite size (La and Lc) and edge dislocation density. CTP-1GO-5TiB2 shows a compressive strength 194.7 MPa higher than the pure CTP (155.4 MPa). Further findings suggest that a combined mechanism of GO and TiB2 additions can be established through stabilizing C–C bonds while reducing C-O bonds along with chemical component transformations after pyrolysis and carbonization. TiB2 particles play a key role in making the synergistic effect on improving the mechanical strength and reducing the oxidation of C–C bonds with additional increase in La value.

Effect of Calcination Time on the Microstructure and Optical Properties of (Zn<sub>0.5</sub>Cu<sub>0.5</sub>)Al<sub>2</sub>O<sub>4</sub> Spinel Color Pigments

The (Zn0.5Cu0.5)Al2O4 pigments were synthesized by solid state processing with an aim to examine the kinetics of phase formation. The calcining temperature was 1100 °C with firing times of 2, 12, 24, 48 and 96 hours during which intermediate grinding was carried out. All five obtained pigment samples appeared to be single-phase as probed by XRD. However, lattice refinement revealed differences in the lattice constant which kept decreasing and reached constancy after 24 hours of firing. Such reduction in the lattice constant was associated with incorporation of smaller copper cations into the Zn-sites. FTIR spectra also supported this result as the relevant peaks still got broadened and shifted for the calcination times of less than 48 hours. Elemental analysis of the 2-hour sample showed small presence of starting precursor particles, though not detected by XRD, suggesting an incomplete reactivity at a minute scale. These structural changes were resultantly reflected by small but significant alterations in the color parameters. A higher degree of solid solution for the samples fired for longer times, as judged by lowering in the lattice constant, resulted in detectable changes in both a and b parameters. Longer calcination times yielded a brighter (higher L values) brownish tone likely due to both diminution in the averaged particle size from pulverizing and completion of solid solution. The first would be useful for good dispersion in glazes whereas the latter could be directly related to the degree of cationic substitution, confirming the expected “true” color for this specific doping level at a particular calcination temperature.

Constructing highly utilizable Fe-N4 single-atom sites by one-step gradient pyrolysis for electroreduction of O2 and CO2

Fe-N4 single-atom catalysts (SACs) have been investigated extensively in various energy conversion reaction. However, large amount of untouchable Fe-N4 sites buried in the dense carbon skeletons greatly restrict the maximization of catalytic performance. Therefore, rational construction of catalyst nanostructure to effectively expose Fe-N4 single atom sites is eagerly desired. Here, we report a one-step gradient pyrolysis method by using quaternary ammonia polysulfone (QAPS) polymer with a lower carbonization temperature to segregate precursor particles (ZIF-8 and polyaniline) to construct mesopores at 4–9 nm, thereby tellingly increasing the accessibility of Fe-N4 single atom sites. Nitrite reduction method revealed that the prepared catalyst had a three-fold increase in active sites density compared to catalyst without QAPS. Thus, it exhibits a terrific peak power density (1.15 W cm−2) in proton exchange membrane fuel cells and a superior CO partial current density (121 mA cm−2) with 99 % Faradaic efficiency for CO at 0.5 V in flow cells.

Mass transport in binary TiO2:SiO2 and GeO2:SiO2 direct ink write glasses

AbstractThe mass transport mechanisms of Ti in TiO2:SiO2 and Ge in GeO2:SiO2 direct ink write, additively manufactured glasses were studied. Due to the low solubility of Ti in SiO2 and high melting point of TiO2 relative to SiO2, Ti transport was found to occur via solid state interdiffusion between adjoining SiO2 and TiO2 precursor particles. The diffusivity of titanium in SiO2 measured over typical sintering temperatures (1000–1300°C) using Rutherford backscattering spectrometry was . This provides an estimate of ∼30 nm for the diffusion length under typical sintering conditions (2 h at 1200°C). Although Ti and Ge have similar diffusivities in SiO2 glass at low concentrations, GeO2 was found to be much more mobile during the sintering of printed GeO2:SiO2 green bodies. This was evident in glasses with phase separated GeO2 regions over length scales of ∼10 µm and in experiments involving binary xerogel films in which GeO2 migrated over ∼10 µm through cracked, porous SiO2 layers. Large phase separated regions and long transport lengths in GeO2:SiO2 suggest that the transport of GeO2 occurs prior to the densification of the SiO2 matrix via an alternative mechanism such as capillary flow. These results inform important considerations in the design of index modifying inks for the direct ink write process, namely initial precursor phase, mutual solubility with the base SiO2 glass, and mass transport throughout the sintering process.

Effect of late intake valve closing on the particle number emissions of a turbocharged gasoline direct injection engine

To achieve carbon-neutrality, efficient gasoline engines with minimal particle number emissions are being increasingly researched. In this study, the particle emission mechanism associated with late intake valve closing (LIVC) was investigated using borescopic method, and particle image velocimetry (PIV) in a 4-cylinder turbocharged gasoline direct injection engine, and a 2-cylinder optically accessible engine, respectively. The direct flame visualization of the borescope and flow visualization of the PIV measurement were used to analyze the blue flame propagation characteristics, mean in-cylinder flow velocity, and turbulent kinetic energy associated with the LIVC along with combustion analysis. The retardation of the LIVC timing reduced the particle number emissions, increased the in-cylinder flow velocity, and decreased the effective compression ratio. The improved flow velocity and reduced effective compression ratio mitigated the production of particle precursors at the expense of decelerated initial flame propagation. However, this decelerated flame propagation was compensated by the enhanced late-stage combustion generated from the increased turbulent kinetic energy of the retarded LIVC timings. The obtained results verify that the improved mixture formation and initial lower in-cylinder temperature conditions of the retarded LIVC timing reduced the particle production, which in turn enhanced the particle oxidation owing to the accelerated late-stage combustion.

Synthesis routes for multi-shape Fe3O4 nanoparticles through oxidation-precipitation of hematite and modified co-precipitation method without surfactant

Uniform fine particles of iron oxide were precipitated in different morphologies through forced hydrolysis and co-precipitation. The effect of reaction parameters on particle uniformity and morphology was studied, and SEM analysis explored that particle morphological features were strongly affected by the applied reaction conditions. Therefore, monodispersed particles of magnetite precursors with narrow size distribution were prepared under the extensively optimized experimental parameters. The growth mechanism of the precipitated solids was observed to be sensitive to the medium temperature and pH, as high temperature and pH resulted in large particles. In contrast, small particles were precipitated at low temperatures and pH. Magnetite nanoparticles were precipitated directly through co-precipitation under controlled reaction conditions and from the calcination of the as-synthesized hematite at high temperatures. Their SEM demonstrated that calcination at high temperatures affected the particle morphology to a greater extent along with the phase transformation. Similarly, XRD and FTIR analysis of the as-prepared magnetite particles from two routes confirmed the single-phase magnetite. The response of the as-prepared particle systems to the higher temperature and composition of the surface groups was analyzed by TG/DTA and FT-IR techniques.

Studies on the Competition Between Homogeneous and Heterogeneous Ice Nucleation in Cirrus Formation

AbstractCirrus ice crystals are produced heterogeneously on ice‐nucleating particles (INPs) and homogeneously in supercooled liquid solution droplets. They grow by uptake of water molecules from the ice‐supersaturated vapor. The precursor particles, characterized by disparate ice nucleation abilities and number concentrations, compete for available vapor during ice formation events. We investigate cirrus formation events systematically in different temperature and updraft regimes, and for different INP number concentrations and time‐independent nucleation efficiencies. We consider vertical air motion variability due to mesoscale gravity waves and effects of supersaturation‐dependent deposition coefficients for water molecules on ice surfaces. We analyze ice crystal properties to better understand the dynamics of competing nucleation processes. We study the reduction of ice crystal numbers produced by homogeneous freezing due to INPs in both, individual simulations assuming constant updraft speeds and in ensemble simulations based on a stochastic representation of vertical wind speed fluctuations. We simulate and interpret probability distributions of total nucleated ice crystal number concentrations, showing signatures of homogeneous and heterogeneous nucleation. At typically observed, mean updraft speeds (≈15 cm s−1) competing nucleation should occur frequently, even at rather low INP number concentrations (<10 L−1). INPs increase cirrus occurrence and may alter cirrus microphysical properties without entirely suppressing homogeneous freezing events. We suggest to improve ice growth models, especially for low cirrus temperatures (<220 K) and low ice supersaturation (<0.3).

Oilothermal, a novel pyrolysis method for fabrication of carbon dots-loaded carriers from cyanobacteria for use in solid-phase extraction of cadmium

BackgroundMaking carbon dots-loaded carriers (CLCs) required the use of two types of precursors (one for carrier particles and the other for carbon dots) and at least three steps. In this study, CLCs were fabricated by using cyanobacterial cells as a dual-purpose precursor and oilothermal as an innovative pyrolysis method. MethodsThe oilothermal method allowed that each cyanobacterial cell (carrier particle precursor) with its hydrous exopolysaccharides (EPSs) layer (carbon dots precursor) to be encapsulated together by an oil micelle and pyrolyzed separate from other cells and formed the CLC in one step. The potential of emerging CLCs for solid-phase extraction (SPE) was assessed. For this purpose, the CLCs were tested in a cadmium-based model. Significant findingsThe range of the maximum pH-dependent adsorption efficiency (>95%) was extensive (pH 4–10). The adsorption kinetics and isotherm had the best fit with the pseudo-second-order and Langmuir linear models, respectively. The adsorption capacity was 5305.61 mg kg−1 only in 2 min exposure time. The findings in this research conclude that emerging CLCs, because of their unique features such as high capacity, fast adsorption rate, fast recovery rate, green origin, optimal and efficient fabrication method, have a high potential for SPE of trace cadmium.

Effect of the Stirring Velocity and the SiO2 Precursor Particles Feeding Rate on the Microstructure of the Al2O3/SiO2/Al Composites Prepared via Stir Casting Process

Stir casting has been taken as a low cost and effective way to disperse ceramic particles in molten alloys and obtain the high‐performance metal matrix composites. However, the reinforcement precursors with a similar density to the molten aluminum are difficult to be uniformly dispersed in the melts. Herein, the particulate quartz, which can react with the aluminum melts and form the Al2O3/SiO2 reinforcement, is used as the reinforcement precursor. Effect of the stirring speeds of the melts and the feeding rates of precursor particles on the reinforcement distribution in aluminum matrix are investigated. The numerical simulation is carried out to analyze the particles dispersion course in the melts. Results show that the precursor particles in molten aluminum achieve a relatively uniform dispersion at the modest stirring rate of 400 rpm. Meanwhile, numerical simulation results also prove that precursor particles will distribute homogenously in the Al matrix while exerting the stirring rate at 400 rpm. From the microstructure of the composites, it is evident that extremely high stirring rate and particles feeding rate will lead to the agglomeration of particles, which is not favorable to the composites performance.

Improvement of barium tungsten cathode and investigation of thermionic emission performance

<sec>The Ba-W cathode consists of the porous W matrix and the aluminate. During cathode operation, the Ba atoms are generated in the pores through the thermal reaction between the W and aluminate, and then diffuse along the pore channels to the W surface, lowering the work function. Therefore, the Ba yield and the Ba diffusion are significantly influenced by the micro pore structure of the matrix and the phase composition of the aluminate.</sec><sec>Firstly, the matrix is fabricated with the narrow particle size distribution powder by the spark plasma sintering (SPS) technique, which shows the narrow pore size distribution (FWHM = 0.43 μm). Then the spherical powder with good fluidity and high tap density is prepared using the RF induction thermal plasma. The matrix prepared with spherical powder exhibits narrower pore size distribution (FWHM = 0.4 μm), smooth pore channels and good inter-pore connectivity. The two matrixes prepared with narrow particle powder and spherical powder are named N-matrix and S-matrix, respectively.</sec><sec>The aluminates are prepared using the solid phase method and the liquid phase method, separately. The particles of solid phase aluminate precursor present all shapes and all sizes, while the particles of the liquid phase aluminate precursor are uniform in size and identical in shape. The phase of solid phase aluminate and the phase of liquid phase aluminate are analyzed by XRD, the results show that the former consists of the effective Ba<sub>3</sub>CaAl<sub>2</sub>O<sub>7</sub> phase and other impurity phases, while the latter is composed of two effective phases of Ba<sub>3</sub>CaAl<sub>2</sub>O<sub>7</sub> and Ba<sub>5</sub>CaAl<sub>4</sub>O<sub>12</sub>.</sec><sec>The N+S and S+S cathodes are obtained by using the solid phase aluminate to impregnate the N-matrix and the S-matrix, and the <i>U</i>-<i>j</i> characteristics of the two cathodes are investigated. The double logarithmic curves of <i>U</i> and <i>j</i> show that the slope of 1.37 in the space charges limited (SCL) region for the S + S cathode is higher than that of 1.25 for the N+S cathode, so the S+S cathode exhibits better emission uniformity. The current density at the deviation point (<i>j</i><sub>DEV</sub>) of the N+S cathode and that of the S+S cathode are 6.6 A·cm<sup>–2</sup> and 6.96 A·cm<sup>–2</sup>, respectively. So the improvement on the matrix obviously raises the emission uniformity of cathode, but the current density is increased less.</sec><sec>Based on the excellent matrix of the S+S cathode, the S+L cathode is obtained by improving the aluminate of the S+S cathode with liquid phase aluminate. The <i>U</i>-<i>j</i> characteristics show the slope of the S+L cathode reaches to 1.44, and the <i>j</i><sub>DEV</sub> is 21.2 A·cm<sup>–2</sup>. So the improvement on the aluminate not only increases the uniformity, but also raises the current density.</sec><sec>The present study shows that the <i>U-j</i> curve calculated from the classical thermionic emission (TE) theory accords well with that of the S + L cathode at 1000 ℃, which indicates that the Ba-W cathode follows the classical TE theory rather than other emission theories, and the Ba-O dipole layer just changes the work function of the cathode.</sec>

The evolution of soot morphology for the maturation of nascent particle in a turbulent lifted jet flame

In order to understand the soot formation in Diesel engine, a turbulent jet flame is used to simulate the combustion in the cylinder. The experimental study is performed to investigate the evolution of soot morphology for the maturation of nascent particle in a turbulent lifted jet flame fueled by n-heptane/toluene mixtures. An ultrasonic atomizer is used to evenly spread the fuel droplets to acquire single primary particles. Transmission electron microscopy is used to study the morphology of the particle sampled from the flame at different heights. Small soot aggregates are acquired from all the samples. Particle maturation such as agglomeration is accelerated under a high temperature by comparing the particle morphology sampled on the centerline and the wings of the flame. The precursors of nascent particles are depicted as dark nucleation dispersed to semitransparent polycyclic aromatic hydrocarbons. The nanostructure of nascent particles transforms from an amorphous state to an onion structure with the maturation of particles. Surface growth initially dominates the maturation of nascent particles in the direction of outside to inside for single particles. Agglomeration begins to emerge with the increased probability of collision at the end of maturation. Surface growth and agglomeration increase the mean particle diameter as the flame height increases. The oxidability of particles that undergo surface growth and agglomeration notably increases. The structure of nascent particles is inclined to be ordered and the mean particle diameter decreases with oxidation dominating the combustion reaction.

Structure and magnetic properties of nitrides in FeNi and FeNiCo alloy particles synthesized via co-precipitation, reduction, and nitriding

Nitriding of FeNi and FeNiCo alloy particles was attempted. Precursor particles were synthesized by co-precipitates of Fe, Ni, and Co ions with the following compositions: Fe/Ni: 0.5/0.5 and Fe/Ni/Co: 0.5/0.45/0.05. The precursor particles were first reduced in hydrogen gas to obtain FeNi and FeNiCo alloy particles. Both the alloy particles were confirmed to have face-centered cubic (fcc) structures. Nitriding was subsequently performed using a mixture of ammonia and nitrogen gases. The formation of monophase (Fe0.5Ni0.5)4N and (Fe0.5Ni0.45Co0.05)4N was observed by the nitriding of the FeNi and FeNiCo alloy particles. No significant change in particle shape was observed by nitriding. Both the coercive force and saturation magnetization decreased by nitriding compared with those of the FeNi and FeNiCo alloy particles. Mössbauer analyses showed that Site I was preferentially occupied by Ni, and Site II was occupied by Fe and Ni with a Ni/Fe: 1/2 ratio in FeNi nitride particles. A similar spectrum to that of the FeNi nitride particles was observed in the FeNiCo nitride particleswith a slightly increased average hyperfine field corresponding to the increase in magnetization.

Understanding the particulate formation process in the engine fuelled with diesel/Jet A-1 blends

Jet fuel has been recognized as a potential alternative for traditional diesel engines because of its ability to reduce particulate matter (PM) emissions while retaining engine power output. In this study, the particulate formation process has been studied in detail using diesel/Jet A-1 blends with evenly staggered ratios. The number concentration of the accumulation mode particle decreases exponentially when additional Jet A-1 is introduced to the blends under 30% engine load, as more fuel and particle precursors are oxidized. Additionally, the comparison of PM emissions with pilot-main and single main two injection strategies is conducted to better understand the particle formation process. The phenomenon of ‘particle saturation’ of nucleation mode particles is observed using the pilot-main injection strategy. With these supporting findings, we strengthen the point that the pilot-injection strategy has the potential weaken the oxidation process during the combustion process. Furthermore, this research quantifies the impact of Jet A-1 on combustion and gas emission characteristics by extracting the change rate from the data. In general, Jet A-1 tends to delay the ignition and shorten the combustion duration. The results also reveal that the rise in NOx emissions is due to a higher proportion of premixed combustion, while the increase in HC emissions is attributed to a longer ignition delay and shorter combustion time.

Simultaneous Quantitative Detection of HCN and C2H2 in Combustion Environment Using TDLAS

Emission of nitrogen oxides (NOx) and soot particles during the combustion of biomass fuels and municipal solid waste is a major environmental issue. Hydrogen cyanide (HCN) and acetylene (C2H2) are important precursors of NOx and soot particles, respectively. In the current work, infrared tunable diode laser absorption spectroscopy (IR-TDLAS), as a non-intrusive in situ technique, was applied to quantitatively measure HCN and C2H2 in a combustion environment. The P(11e) line of the first overtone vibrational band v1 of HCN at 6484.78 cm−1 and the P(27e) line of the v1 + v3 combination band of C2H2 at 6484.03 cm−1 were selected. However, the infrared absorption of the ubiquitous water vapor in the combustion environment brings great uncertainty to the measurement. To obtain accurate temperature-dependent water spectra between 6483.8 and 6485.8 cm−1, a homogenous hot gas environment with controllable temperatures varying from 1100 to 1950 K provided by a laminar flame was employed to perform systematic IR-TDLAS measurements. By fitting the obtained water spectra, water interference to the HCN and C2H2 measurement was sufficiently mitigated and the concentrations of HCN and C2H2 were obtained. The technique was applied to simultaneously measure the temporally resolved release of HCN and C2H2 over burning nylon 66 strips in a hot oxidizing environment of 1790 K.

Iron-based oxygen carrier particles produced from micronized size minerals or industrial wastes

The production of highly reactive oxygen carrier particles based on low-cost iron materials is explored for chemical looping processes. Ten different low-cost Fe-based materials in the micronized size, both minerals and industrial residues, have been tested as precursors of oxygen carrier particles. The redox reactivity of each of the materials is evaluated and compared to the state-of-the art with particulate materials, including one new material introduced in this work. Due to its excellent reactivity, Promifer material was used to produce oxygen carrier particles by pelletizing and granulation. Considering a trade-off between crushing strength and reactivity, pelletizing process was selected. This material calcined at 950 °C showed high reactivity with CH4. If a higher operating temperature was required, e.g. 1000 °C with solid fuels, the reactivity decreased. Low attrition rates and good fluid-dynamic behavior with the pelletized particles, without agglomeration along the redox cycles, were found in a fluidized bed reactor.

Assessment of Water Soluble Ionic Composition of Respirable Particulates from the Coastal Region, Gandhidham-Kachchh, Gujarat, India

Gaseous pollutants serve as precursors of ionic particles in the atmospheric environment, thus their control is necessitated along with the particulate with special reference to soluble ions. The present study was undertaken to assess the effect of Particulate Matter (PM10) associated Water-Soluble Ions (WSI) on the ambient air concentration. In total 134 airborne particulate matter (PM10) samples were collected from 11 stations from January to December in and around Gandhidham, Gujarat, India. Monthly sampling was carried out by the Respirable Dust Sampler (RDS) on 24 hr basis. The samples were subjected to chemical analyses for estimating water-soluble ions. The PM10 concentration in the analyzed samples ranged from 29 to 401 µg/m3. The amount of Na+, Ca2+ and K+ varied from 0.04 to 8.43 µg/m3, Below Detection Level (BDL) to 12.25 µg/m3, and 0.09 to 3.49 µg/m3, respectively following flame photometer method. The anions SO 2-, NO - and Cl- ranged from 0.31 to 3.68 µg/m3, 0.39 to 32.47 µg/m3, and 4.03 to 54.08 µg/m3, respectively. Higher concentrations were reported for all the ions during winter. From the results, it is evident that secondary anthropogenic aerosols, natural mineral aerosols and mixed sea salt contributed to higher ionic concentrations in the air.

Association of snR190 snoRNA chaperone with early pre-60S particles is regulated by the RNA helicase Dbp7 in yeast

Synthesis of eukaryotic ribosomes involves the assembly and maturation of precursor particles (pre-ribosomal particles) containing ribosomal RNA (rRNA) precursors, ribosomal proteins (RPs) and a plethora of assembly factors (AFs). Formation of the earliest precursors of the 60S ribosomal subunit (pre-60S r-particle) is among the least understood stages of ribosome biogenesis. It involves the Npa1 complex, a protein module suggested to play a key role in the early structuring of the pre-rRNA. Npa1 displays genetic interactions with the DExD-box protein Dbp7 and interacts physically with the snR190 box C/D snoRNA. We show here that snR190 functions as a snoRNA chaperone, which likely cooperates with the Npa1 complex to initiate compaction of the pre-rRNA in early pre-60S r-particles. We further show that Dbp7 regulates the dynamic base-pairing between snR190 and the pre-rRNA within the earliest pre-60S r-particles, thereby participating in structuring the peptidyl transferase center (PTC) of the large ribosomal subunit.

Unveiling Sodium Ion Pollution in Spray-Dried Precursors and Its Implications for the Green Upcycling of Spent Lithium-Ion Batteries.

Unclear impurity pollution is one of the key scientific problems that limit the large-scale production of new lithium-ion batteries (LIBs) from spent LIBs. This work is the first to report the pollution path, pollution degree, and solution method of sodium ions in the recycling process of spent LIBs in the real world. The results show that sodium ions can intrude into the precursor particles to form crystalline salts with the anion of the leaching acid that cover the transition metal elements, thereby resulting in a failed precursor. Specifically, the intrusion of sodium ions will produce a variety of pollutants containing metal oxide bonds, such as Na-O, NaO2, and Na+-O2, on the precursor surface. These active lattice oxygen will further adsorb or react to form organic oxygen, chemical oxygen, and free oxygen, which will highly deteriorate the surface cleanliness. Strictly controlling the consumption of sodium salt in each step and using ammonia instead of NaOH for pH regulation can effectively solve sodium ion pollution to prepare high-quality battery precursors. It reveals that for the green upcycling of spent LIBs, we should strengthen the design of the recycling process to reduce the consumption of chemical reagents, which will produce unexpected secondary pollution.

Thin Lithium Metal Foil Technology for Advanced Battery Manufacturing

Lithium metal anode is regarded as the holy grail for the next generation battery materials due to its high theoretical specific capacity which is 10 times higher than that of graphite1. Currently, the most advanced lithium-ion battery cells have energy density of ~300 Wh/kg. Whereas, lithium metal batteries with liquid or semi solid electrolyte from Solidenergy2 and Sion Power3 have demonstrated record specific energy density of over 400 Wh/kg. Solid-state batteries use non-flammable solid electrolytes instead of liquid and, therefore, offer improved safety. The 20 Ah multi-layer all solid-state cells made by Solid Power have achieved 330 Wh/kg.4 However, solid state batteries can exceed the energy density of today's lithium-ion batteries only when the thin lithium metal foil (<20 um thickness) is used as anode enabling a pathway to beyond 400Wh/kg.Industrial scale thin Lithium metal foil is produced by hydraulic extrusion followed by a rolling process. This process usually requires a delicate balance between the pressure and tension created by both extruder and winder, so that the resulting foil is not torn or stretched, retaining all the dimensional characteristics required. This process can be extremely challenging when making lithium metal films with thickness less 20 µm due to the poor mechanical properties of lithium metal.5 Moreover, the cost of making these foils dramatically increases as the thickness decreases. Livent has recently developed Printable Lithium Technology (PLT), which incorporates stabilized lithium metal powder (SLMP®) into a stable printable formulation. This presentation will cover thin lithium foil manufacturing processes and highlight advantages and disadvantages of our approach. The electrochemical performance results will be presented.Figure 1A compares the 50 μm commercially available lithium foil (left) and 20 μm printed lithium foil (right) laminated to copper current collector. Figure 1A shows that a uniform film made from printable lithium formulation is consistent across the application area. Figure 1B and figure 1C are the optical microscope images of 50 μm commercially available lithium foil and 20 μm printed lithium foil, respectively. Figure 1B shows commercial foil made with conventional extrusion and rolling process has rough and scratched surface. Figure 1C shows that printed lithium foil preserves the shape of precursor particles and boundaries are formed creating higher surface area that potentially can mitigate dendrite growth by distributing current over a wider area. Figure 1D and 1E show the SEM and EDS images of the printed Lithium foil after lamination. Figure 1D and 1E show the clear presence of oxygen at the boundaries. Figure 1F shows the microscope image of printed lithium foil before calendering which is a monolayer. Figure 1G compares lithium plating and stripping properties of testing conducted in a symmetric pouch cell format with a current collector coated with 20 um printed lithium foil vs. 50 um commercially available lithium foil. Figure 1G shows that the cell containing the printed lithium foil, with lower thickness, has exceptional cycling stability with negligible potential increases during the first 70 cycles, indicating that the growth of dendritic lithium has been significantly mitigated.Figure Captions: Figure 1A. Image of 50 μm commercially available lithium foil (left) and 20 μm printed lithium foil (right) on a copper current collector. Figure 1B. Microscope (200x) image of the Printed Lithium Foil before lamination. Figure 1C. SEM Image (500x) of the Printed Lithium Foil after lamination. Figure 1D Microscope image of 50 μm commercially available lithium foil. Figure 1E. Microscope image of 20 μm printed lithium foil. Figure 1F. EDS surface mapping of oxygen for the printed foil. FIG. 1G. Lithium plating and stripping properties tested in a pouch cell with a copper current collector coated with 20 μm printable lithium formulation compared to 50 μm commercially available lithium foil. Cycling voltage is between -0.5V and 0.5 V and a current density is 0.5 C for 1h. References D. Lin, Y. Liu, and Y. Cui, Nature Nanotechnology, 12, 194–206 (2017) http://dx.doi.org/10.1038/nnano.2017.16.Q, Hu, Y. Matulevich and Y, Tang, Solidenergy Systems, US Patent No. 16/308,023, June 08th, 2016https://sionpower.com/2021/sion-power-announces-licerion-ev-targeting-electric-vehicles-with-a-large-format-17-ah-400-wh-kg-cell/https://www.greencarcongress.com/2020/12/20201216-solidpower.htmlO. Mashtalir, M. Nguyen, E. Bodoin, L. Swonger, and S. P. O’Brien, ACS Omega, 3, 181–187 (2018).Shu-Hua Wang et al., Nat. Commun.2019,10,4930 Figure 1