Homogeneous Pore Size Research Articles

Paracetamol and Ibuprofen Removal from Aqueous Phase Using a Ceramic-Derived Activated Carbon.

Emerging pollutants, including pharmaceuticals and personal care products, have been detected in surface and groundwaters. The adsorption of paracetamol and ibuprofen, two widespread drugs, has been studied in aqueous medium, using a ceramic-derived carbon (CeDC) and a commercial activated carbon (CoAC). CeDC yielded a BET surface area of 895 m2 g−1, a bimodal pore size distribution (13.2 and 35 nm) and a total pore volume of 1.99 cm3 g−1. CoAC had an approximate surface area of 1000 m2 g−1, a homogeneous pore size distribution and a total pore volume of 0.42 cm3 g−1. Kinetic and equilibrium tests were carried out in batch systems to study the materials’ sorption performances. The intraparticle diffusion model best fitted the experimental kinetic data. The maximum ibuprofen sorption capacities were 120 mg g−1 and 133 mg g−1 for CoAC and CeDC, respectively, whereas no major differences on the maximum paracetamol sorption capacities (qm) were observed among the sorbents (150–159 mg g−1). Therefore, CeDC, synthesized easily from a ceramic composite, improved time and sorption capacity of paracetamol and ibuprofen compared to the commercial activated carbon, indicating the potential of the developed carbon as an emerging pollutant sorbent material.

High performance supercapacitors using selenium partially reduced Co3O4 on carbon cloth electrode with 3D interconnected architecture nanowires

The electrodes with high conductivity, large specific surface area and homogeneous pore size distribution are greatly desirable for supercapacitors applications. Herein, a hydrothermal and subsequent annealing approach was adopted to fabricate 3D interconnected nanowires architecture of selenium partially reduced spinel Co3O4 grew on the carbon cloth (COS@CC). The binder-free COS@CC electrode displays excellent specific capacitance, 1046.9 C g−1 at 1 A g−1, superior rate capability, 51.6% capacitance retention and superior cyclic stability, 92.0% capacitance retention after 15,000 cycles. These electrochemical performances were found to be better than that of the Co3O4@CC electrode. The enhanced electrochemical performance was ascribed to the fact that 3D interconnected architecture nanowires could shorten the ion transfer distance and heighten the rate of the redox reaction. In addition, increased specific surface area and homogeneous mesopore size distribution could assist effective diffusion and transfer of OH– between electrodes and electrolyte. The enhancement of conductivity, which is caused by the selenium partial reduction and more oxygen vacancies in the structure, facilitates electrons transfer and consequently improves the electrochemical properties of supercapacitors. These remarkable electrochemical performances indicate that the CSO@CC can be employed for developing high-energy and power-density supercapacitors.

Evaluation of the impact of pH of the reaction mixture, type of the stirring, and the reagents' concentration in the wet precipitation method on physicochemical properties of hydroxyapatite so as to enhance its biomedical application potential.

Hydroxyapatite (HAp) constitutes a significant inorganic compound which due to its osteoinductivity, osteoconductivity as well as the ability to promote bone growth and regeneration is widely applied in development of biomaterials designed for bone tissue engineering. In this work, various synthesis methodologies of HAp based on the wet precipitation technique were applied, and the impact of pH of the reaction mixture, the concentration of individual reagents as well as the type of stirring applied (mechanical/magnetic) on the properties of final powders was discussed. Spectroscopic methods (Fourier transform infrared, Raman) and X-ray diffraction allowed to verify the synthesis parameters leading to obtaining calcium phosphate with 96% HAp in phase which indicated higher homogeneity of obtained powder (93.4%) than commercial HAp. Powders' morphology was evaluated using microscopic techniques while specific surface area was determined via Brunauer-Emmett-Teller analysis. Particle size distribution, porosity of powders, and stability of HAp suspensions were also characterized. It was proved that synthesis at pH=11.0 using mechanical stirring resulted in calcium phosphate with a high phase homogeneity and homogeneous pore size distribution (6-20 nm). Moreover, obtained HAp powder showed 71.8% more specific surface area than commercial material-that is, 110 m3 /g for synthetic HAp and 64 m3 /g in the case of commercial powder-which, in turn, is significant in terms of its potential application as carrier of active substances. Thus it was demonstrated that by applying appropriate conditions of HAp synthesis it is possible to obtain powder with properties enhancing its application potential for medical purposes.

Fabrication of anti-fouling and photocleaning PVDF microfiltration membranes embedded with N-TiO2 photocatalysts

Polyvinylidene fluoride (PVDF) membranes are promising materials for purifying and recycling wastewater in cold regions due to their high mechanical strength and low temperature stability. However, in practical wastewater treatment services, PVDF is easily fouled by organic pollutants because of its hydrophobic characteristics. In addition, because of the large amount of reagent utilized in the conventional cleaning process, a new hydrophilic membrane with simple cleaning characteristics needs to be developed. In this work, a novel anti-fouling membrane (N-TiO2@PVDF) was obtained by implanting a N-TiO2 photocatalyst into a PVDF membrane. N-TiO2@PVDFshows a more homogeneous pore size distribution and a larger average pore diameter, which results in a higher water flux (1017.8 L/m2•h compared to 217.4 L/m2•h PVDF), higher model pollutant bovine serum albumin (BSA) solution flux and higher BSA rejection rate (92.3% compared to 81.4% for PVDF). Furthermore, N-TiO2@PVDF shows an outstanding hydrophilicity performance compared to the PVDF membrane. The water contact angle of N-TiO2@PVDF 14 decreases sharply from 93.7° (PVDF) to 53.5°, and the BSA adsorption amount decreases significantly from 1.41 mg/cm2 (PVDF) to 0.05 mg/cm2. The total fouling ratio of N-TiO2@PVDF is decreased to a value of 25.5% compared to a value of 70.3% for PVDF, and the irreversible BSA fouling ratio is even decreased to 5.8% compared to 57.2% for PVDF. This result indicates that N-TiO2@PVDF shows outstanding antifouling performance. The N-TiO2@PVDF membrane also has a photocleaning function, and the BSA flux recovery ratio reaches up to 94.7% under simulated sunlight irradiation for 2 h without additional treatment. The results obtained from hydroxyl radical (OH) detection indicate that OH degradation of organic pollutants is the dominant mechanism for the N-TiO2@PVDF photocleaning. This anti-fouling and photocleaning N-TiO2@PVDF membrane offers a solution to wastewater treatment problems of membrane brittleness and easy fouling in cold places. It can also be a good choice for the drinking water purification process.

The preparation and properties of high-strength porous mullite ceramics by a novel non-toxic gelcasting process

A novel approach to fabricate porous mullite ceramics with homogeneous pore size and high-strength using green non-toxic and cost-effective poly-γ-glutamic acid (γ-PGA) gelling system was reported for the first time. Effect of γ-PGA addition, additive amount and solid loading on rheological behavior of the slurries, and microstructure and properties of samples were investigated systematically. By optimizing the solid loading of mullite samples, we are able to get the sample with small pores (< 200 µm) dominating (93.3% of the total pores), and compressive strength of the sample reaches up to 26.62 MPa. In addition, the mullite ceramics exhibited high porosity of 75.7% with low thermal conductivity of 0.279 W/(m·K) at room temperature. This study not only provides a green and non-toxic gelling system but also offers porous mullite ceramics with low thermal conductivity and excellent mechanical strength as an energy-saving thermal insulation material.

Size-controlled mesoporous magnetic silica beads effectively extract extracellular DNA in the absence of chaotropic solutions

Due to lack of universally effective extraction methods, the importance of extracellular DNA (exDNA) in natural environments to DNA studies has been largely overlooked in favor of intracellular DNA. In this study, a novel method using size-controlled mesoporous silica magnetic nanoparticles (MSCMNPs) was proposed to extract extracellular DNA from various environments. MSCMNPs have an ordered mesopores structure with homogenous pore size at around 3.0 nm. This structure contributes to superior DNA adsorption of MSCMNPs in the absence of chaotropic solutions in terms of capacity (833.3 mg/g), velocity (0.028/s), and lengths of exDNA that can be extracted, including highly fragmented exDNA (less than 100 bp). This high affinity for DNA also allowed MSCMNPs to resist interference by competitive compounds. Furthermore, exDNA adsorbed onto MSCMNPs could be effectively eluted in Tris-EDTA buffer at 60 ℃ for 5 min. Thus, MSCMNPs are promising for extracting exDNA from various environmental samples including wastewater effluent, activated sludge, freshwater river, and soil samples, with the recovery efficiencies between 83.4% and 95.8%. This study is of importance to advance exDNA research in various environments lacking effective exDNA extraction methods.

METHANOL MASS VARIATION OF MESOPOROUS SILICA SYNTHESIS USING RICINOLEIC METHYL ESTER AS A TEMPLATE

This study aims to synthesize mesoporous silica using ricinoleic methyl ester as a template with the variation of methanol mass. Mesoporous silica was synthesized using ricinoleic methyl ester as a template, 3-aminopropyltrimethoxysilane as a structural directing agent, and tetraethyl orthosilicate (TEOS) as a source of silica. The novelty of this study lies in the use of ricinoleic methyl ester as a template. The reaction conditions were varied by varying the amount of methanol without adding hydrochloric acid 0.1M. The yield of mesoporous silica in samples named MSME A, MSME B, and MSME C was 1.63 g, 1.70 g, and 1.80 g. It shows that adding methanol mass affects the yield of mesoporous silica. Fourier-transform infrared spectroscopy (FTIR) analysis revealed that all silica products formed Si-O-Si bonds between 1103 cm-1 and 1111 cm-1 due to asymmetric stretching vibration. All silica products have a diffractogram at 2θ between 10o and 30o, indicating amorphous. The scanning electron microscope (SEM) image demonstrates the mesoporous silica morphology as a mixture of spherical particles and multiple sheets, fused round particles, aggregated particles, and spreading spherical particles. The BET analysis reveals a homogeneous pore size distribution in the third and fourth treatments. Each is dominated by a pore size range of 8.43 nm to 8.50 nm.

Structural comparison of commercially available face masks using scanning electron microscopy

The fabric structures of re-usable (cotton, polyurethane, polyester 95% with polyurethane 5%, polyester 95% with spandex 5%) face masks compared to disposable non-woven masks were observed under scanning electron microscopy. We found re-usable face masks in general have homogeneous pore sizes of approximately 0.1 - 0.5 mm. In comparison, non-woven masks have two fiber layers separated by one densely non-woven labyrinthine layer with disordered three dimensional microfibers. We found most (7 out of 8) non-woven masks shared this similar dense second layer composition. Our observation for masks under the electron microscopy provides structural evidence underlying infection-preventing superiority of non-woven over re-usable (cotton, polyurethane, polyester 95% with polyurethane 5%, polyester 95% with spandex 5%) face masks. Furthermore, we found that non-woven masks do not always have the disordered dense middle layer, which suggests that some products of non-woven masks may not provide equal protection for infection.

Microstructure and mechanical properties of quasi-isotropic chopped fiber-reinforced PyC–SiC matrix composite prepared by novel nondamaging method

In this work, quasi-isotropic chopped carbon fiber-reinforced pyrolytic carbon and silicon carbide matrix (Cf/C–SiC) composites and chopped silicon carbide fiber-reinforced silicon carbide matrix (SiCf/SiC) composites were prepared via novel nondamaging method, namely airlaid process combined with chemical vapor infiltration. Both composites exhibit random fiber distribution and homogeneous pore size. Young's modulus of highly textured pyrolytic carbon (PyC) matrix is 23.01 ± 1.43 GPa, and that of SiC matrix composed of columnar crystals is 305.8 ± 9.49 GPa in Cf/C–SiC composites. Tensile strength and interlaminar shear strength of Cf/C–SiC composites are 52.56 ± 4.81 and 98.16 ± 24.62 MPa, respectively, which are both higher than those of SiCf/SiC composites because of appropriate interfacial shear strength and introduction of low-modulus and highly textured PyC matrix. Excellent mechanical properties of Cf/C–SiC composites, particularly regarding interlaminar shear strength, are due to their quasi-isotropic structure, interfacial debonding, interfacial sliding, and crack deflection. In addition to the occurrence of crack deflection at the fiber/matrix interface, crack deflection in Cf/C–SiC composites takes also place at the interface between PyC–SiC composite matrix and the interlamination of multilayered PyC matrix. Outstanding mechanical properties of as-prepared Cf/C–SiC composites render them potential candidates for application as thermal structure materials under complex stress conditions.

Catalytic pyrolysis of used tires on noble-metal-based catalysts to obtain high-value chemicals: Reaction pathways

A systematic study on the use of noble metals (Pd, Pt, Au) supported on titanate nanotubes (NT-Ti) for selectively producing BTX and p-cymene from waste tire pyrolysis is provided here. All the materials were characterized for chemical, textural and structural properties using a range of analytical techniques. The M/NT-Ti (M: Pd, Pt, or Au) catalysts exhibit low nanoparticle sizes (1.8 <NPs<2.2 nm), and a homogeneous pore size distribution. The catalysts demonstrated excellent activity for converting WT into BTX-enriched oil when tested in a micropyrolysis system coupled to chromatography/mass spectrometry (Py–GC/MS). The BTX production was enhanced by the presence of catalysts with a selectivity order as follows Pd > Pt ≈ Au > support > non-catalyst. The Py-GC/MS suggest that the catalysts participate in the secondary reactions of dealkylation, dehydrogenation, isomerization, aromatization, and cyclization leading to a higher formation of BTX than the uncatalyzed reaction. Finally, a comprehensive reaction pathway describing the catalytic pyrolysis of WT over Pd/NT-Ti was proposed by studying the catalytic pyrolysis of individual polymers constituting the waste tires, and D,L-Limonene.

Integrated sedimentological and petrophysical characterization for clastic reservoirs: A case study from New Zealand

The present study aims at characterizing the sedimentological and petrophysical properties of the Middle-Late Miocene Mt Messenger reservoir in Taranaki Basin, New Zealand. It is a detailed study based on availability of sedimentological (petrography, SEM and XRD), well log data (gamma ray, neutron, density, sonic, shallow and deep resistivity, PEF and RFT logs), in addition to conventional and special core analysis data for Mt Messenger reservoir.The Mt Messenger Formation is considered onshore fan units of low resistivity clastic rocks with high percentage of metamorphic lithic fragments. From the RFT logs, it is composed of two or three compartments partially separated from each other by some tight zones. The reservoir zones are represented by thin beds of well sorted very fine to silty-grained litharenite; sometimes is feldspathic, argillaceous and/or micaceous with very good intergranular porosity of average reaches to 25%. Petrographically and petrophysically four reservoir rock types (RRTs) or hydraulic flow units (HFUs) can be assigned, each with its diagnostic petrophysical properties and storage and flow capacities. The reservoir quality increases to the south at Ngatoro-2 well, where a total of gas- and oil-bearing 5 prospective thin beds are recognized, which are mostly composed of litharenite with very good porosity (21–27.8%) and permeability (63–368 md). Its reservoir quality index (RQI) and flow zone indicator (FZI) indicates fair to good reservoir quality (0.544 = RQI ≤ 1.151 μm, and 1.972 = FZI ≤ 3.049 μm). Presence of argillaceous and/or micaceous materials in addition to the silt-sized grains decreased the reservoir quality from RRT1 samples which are characterized by fair to good reservoir properties (homogeneous pore size distribution, 0.18 = R35 ≤ 1.32 μm) to the RRT4 samples which are considered slightly tight reservoir (slightly heterogeneous pore size distribution, 4.44 = R35 ≤ 9.97 μm).

Electrospun fibrous membrane with controlled hierarchical structure and wettability for effective emulsion separation

Porous membranes are widely used for filtration, especially those with homogenous pore size and strong mechanical strength. Here, we develop a programmable electrospinning system and fabricate porous membranes consisted of orthogonally aligned nanofibers. The porous fibrous membranes possess more homogeneous pore size and stronger mechanical strength when compared to traditional porous membrane with disordered nanofibers. By physically modifying the membrane surface with PTFE nanoparticles, we obtain a filter membrane, which has both large oil contact angle in water and large water contact angle in oil. Synergism between hierarchical structure and surface property realizes a high separation efficiency of both oil-in-water and water-in-oil emulsions. The technique to control the structure of fibrous membrane, combined with the method to modify the surface of nanofibers, provides a great opportunity to design advanced fibrous membrane for various applications.

Microencapsulation of hemp seed oil by pea protein isolate−sugar beet pectin complex coacervation: Influence of coacervation pH and wall/core ratio

The objective of this study was to investigate the impact of coacervation formation pH (3.5 and 2.5) and wall/core ratio (1:1, 2:1 and 4:1) on physicochemical properties of spray-dried hemp seed oil (HSO) microcapsules by means of pea protein isolate (PPI)–sugar beet pectin (SBP) complex coacervates. In general, both phase behaviors and viscoelastic properties of PPI−SBP coacervates were affected by the wall/core ratio. The coacervates structures were highly dependent on the coacervation formation pH, which greatly impacted the spray drying efficiency (PY), encapsulation efficiency (EE), oil distributions in microcapsules and oxidative stability of HSO. At the pHopt (3.5), PPI−SBP complex coacervates possess denser structure owing to the greater electrostatic interaction, whereas softer structure was formed at pH 2.5 as evidenced by rheological properties and FTIR. Because of the homogeneous large pore size and smooth inner surface of liquid coacervates formed at pH 2.5, spray-dried microcapsules had a remarkable higher EE than that formed at pH 3.5. However, the oxidative stability of HSO in PPI−SBP microcapsules prepared at pH 2.5 was significantly shortened due to the weaker electrostatic interaction strength between PPI−SBP, resulting in the partially broken PPI−SBP network caused by the spray drying process. As such, some hollow particle and incomplete particle shape was observed in SEM and CLSM image, which promoted the lipid oxidation of encapsulated HSO. In terms of wall/core ratio, the lower wall/core ratio had lower EE, higher percentage of surface oil on microcapsules, and lower oxidative stability of HSO.

Preparation and characterization of porous zircon aggregates by granulation method: Roles of the polymorphism of Al2O3

In this paper, eight zircon granules were prepared by granulation method, using zircon powders as raw material, α-Al2O3 and γ-Al2O3 as additives and sodium carboxymethyl cellulose (CMC) as binder, respectively. Then, the influence of α-Al2O3 and γ-Al2O3 addition on phase composition, lattice parameters, microstructure and physical characterization were investigated by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results reveal that Al2O3 could influence the Al2O3–ZrSiO4 system by reacting with SiO2 and dissolving into the zircon crystal lattice. The changing of the crystal lattice and the formation of mullite were the main influence factor. The zircon aggregate with 3.0 wt% γ-Al2O3 rendered an optimal apparent porosity of 25.2 %, a high cylinder compressive strength retention rate of 55.1 %, a relatively homogeneous pore size distribution and a smaller changing in lattice parameters.

Tribological Characteristics and Wear Features of Powder Tin Bronze with the Addition of Ultrafine Oxides

The effect of the introduction of ultrafine particles of alumina, nickel oxides and a mixture of their oxides on the mechanical and tribological properties, structure and wear characteristics of powder tin bronze is studied. The increase in the content of alumina from 2 to 5 wt % leads to a decrease in strength by 1.2–1.4 times, and from 5 to 10 wt % it does not affect the change in the tensile strength of powder bronze and leads to a slight decrease in the compressive strength. With an increase in the alumina content from 2 to 10%, the coefficient of friction and the wear rate of powder bronze decrease, and the seizure pressure increases. The addition of nickel oxide to alumina promotes the formation of a homogeneous structure, lower porosity and smaller pore size, an increase in strength, a decrease in coefficient of friction of powder bronze from 0.028 to 0.022, by 2.5 times of wear rate, as well as an increase in seizure pressure from 4 to 7.0 MPa.

Surface modification of magnetic TiO2 core-shell with doped cerium for enhancement of photocatalytic performance

The core-shell structure of Ce-doped TiO 2 @SiO 2 @(Ni-Cu-Zn) ferrite noted of CTSF as composite nanoparticles (NPs) was synthesized using a modified sol-gel method. The physicochemical properties of as-prepared products were characterized completely by X-ray diffraction (XRD), Brunauer-Emmit-Teller (BET), X-ray photoelectron spectroscopy (XPS) and superconducting quantum interference device (SQUID), serially. Meanwhile, assessment of the photocataly s tic activity of catalyst was performed by ultraviolet-visible spectrometry (UV-vis). The results of the study show that the anatase phase related to the TiO 2 structure was constructed on the outer shell coating of composite NPs. However, the second phase associated with the Ce structure was not easy to be detected on the XRD pattern, confirming that the doping Ce had been incorporated into the TiO 2 crystal structure. The mesoporous structure of Ce-doped TiO 2 layers was demonstrated by the type IV isotherm and H3 type hysteresis loop. The homogenous pore size was generated with the specific surface area up to 111.916 m 2 /g and 0.241 cc/g of pore volume. The stoichiometry of the chemical composition formed with fewer defects on the surface of TiO 2 layers was exhibited by the symmetry curve of Ti 2p 3/2 and Ti 2p 1/2 peaks of XPS spectra. Meanwhile, the redox couple corresponding to Ce 3+ /Ce 4+ was incorporated inside the thin TiO 2 coating. Furthermore, the catalyst magnetic NPs can be also separated by using an external magnetic field from the reaction system. The product performance associated with the degradation efficiency was achieved to be 50 % in the aqueous solution of methylene blue (MB)

Erratum to: Ferrocenyl building block constructing porous organic polymer for gas capture and methyl violet adsorption

Ferrocene-based porous organic polymer (FcPOP) was constructed with ferrocene and porphyrin derivatives as building blocks via Schiff-base coupling. FcPOP was well characterized, and exhibited good thermal stability, high porosity, microporous structure, and homogeneous pore size distribution. Ferrocene blocks with highly electron-rich characteristics endowed FcPOP with excellent adsorption capacity of CO2 and methyl violet. The kinetic study indicated adsorption of methyl violet onto FcPOP mainly complied with pesudo-second order model. The maximum adsorption capacity of FcPOP derived from Langmuir isotherm model reached up to 516 mg/g. More importantly, FcPOP could be easily regenerated and repeatedly employed for removal of methyl violet with high efficiency. Overall, FcPOP in the present study highlighted prospective applications in the field of gas capture and dyeing wastewater treatment.

Integration of rock physics and seismic inversion for rock typing and flow unit analysis: A case study

ABSTRACTRock typing and flow unit detection are more challenging in clastic reservoirs with a uniform pore system. An integrated workflow based on well logs, inverted seismic data and rock physics models is proposed and developed to address such challenges. The proposed workflow supplies a plausible reservoir model for further investigation and adds extra information. Then, this workflow has been implemented in order to define different rock types and flow units in an oilfield in the Persian Gulf, where some of these difficulties have been observed. Here, rock physics models have the leading role in our proposed workflow by providing a diagnostic framework in which we successfully differentiate three rock types with variant characteristics on the given wells. Furthermore, permeability and porosity are calculated using the available rock physics models to define several flow units. Then, we extend our investigation to the entire reservoir by means of simultaneous inversion and rock physics models. The outcomes of the study suggest that in sediments with homogeneous pore size distribution, other reservoir properties such as shale content and cementation (which have distinct effects on the elastic domain) can be used to identify rock types and flow units. These reservoir properties have more physical insights for modelling purposes and can be distinguished on seismic cube using proper rock physics models. The results illustrate that the studied reservoir mainly consists of rock type B, which is unconsolidated sands and has the characteristics of a reservoir for subsequent fluid flow unit analysis. In this regard, rock type B has been divided into six fluid units in which the first detected flow unit is considered as the cleanest unit and has the highest reservoir process speed about 4800 to 5000 mD. Here, reservoir quality decreases from flow unit 1 to flow unit 6.

Effect of Al(Oh)3 particle size on microstructures and strengths of porous MgAl2O4 ceramics

Porous MgAl2O4 ceramics were prepared via in-situ decomposition pore-forming (ISDP) technique using Al(OH)3 and magnesite as raw materials. The influence of Al(OH)3 particle size (0-44 μm, 44-88 μm, 88- 100 μm, 100-150 μm) on the microstructures and strengths of porous spinel ceramics were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The bimodal distributions were observed among all the pore size distributions of the porous spinel ceramics. The small pores existed inside the particles and the big pores existed between the particles. When the Al(OH)3 particle size decreased from 100-150 μm to 0-44 μm, the peak of large pores shifted towards left while intensity of the peak of small pores decreased. Simultaneously, the neck-bonds formed between particles grew significantly, which resulted in the increase of compressive strength from 1.4 to 10.8MPa. The optimized product is the sample with the Al(OH)3 particle size of 0-44 μm, which has a high apparent porosity (55.2%), a high compressive strength (10.8MPa) and a relatively homogeneous pore size distribution.

Scalable Freeze-Tape-Casting Fabrication and Pore Structure Analysis of 3D LLZO Solid-State Electrolytes.

Nonflammable solid-state electrolytes can potentially address the reliability and energy density limitations of lithium-ion batteries. Garnet-structured oxides such as Li7La3Zr2O12 (LLZO) are some of the most promising candidates for solid-state devices. Here, three-dimensional (3D) solid-state LLZO frameworks with low tortuosity pore channels are proposed as scaffolds, into which active materials and other components can be infiltrated to make composite electrodes for solid-state batteries. To make the scaffolds, we employed aqueous freeze tape casting (FTC), a scalable and environmentally friendly method to produce porous LLZO structures. Using synchrotron radiation hard X-ray microcomputed tomography, we confirmed that LLZO films with porosities of up to 75% were successfully fabricated from slurries with a relatively wide concentration range. The acicular pore size and shape at different depths of scaffolds were quantified by fitting the pore shapes with ellipses, determining the long and short axes and their ratios, and investigating the equivalent diameter distribution. The results show that relatively homogeneous pore sizes and shapes were sustained over a long range along the thickness of the scaffold. Additionally, these pores had low tortuosity and the wall thickness distributions were found to be highly homogeneous. These are desirable characteristics for 3D solid electrolytes for composite electrodes, in terms of both the ease of active material infiltration and also minimization of Li diffusion distances in electrodes. The advantages of the FTC scaffolds are demonstrated by the improved conductivity of LLZO scaffolds infiltrated with poly(ethylene oxide)/lithium bis(trifluoromethanesulfonyl)imide (PEO/LITFSI) compared to those of PEO/LiTFSI films alone or composites containing LLZO particles.