Oxide Gel Research Articles

Use of Chitosan-Iron Oxide Gels for the Removal of Cd2+ Ions from Aqueous Solutions.

High-quality water availability is substantial for sustaining life, so its contamination presents a serious problem that has been the focus of several studies. The presence of heavy metals, such as cadmium, is frequently studied due to the increase in the contamination levels caused by fast industrial expansion. Cadmium ions were removed from aqueous solutions at pH 7.0 by chitosan-magnetite (ChM) xerogel beads and chitosan-FeO (ChF) xerogel beads in batch systems. Kinetic studies were best modeled by the Elovich model. The adsorption isotherms obtained showed an inflection point suggesting the formation of a second layer, and the BET model adjusted to liquid-solid systems was adequate for the description of the experimental data. Maximum uptake capacities of 36.97 ± 0.77 and 28.60 ± 2.09 mg Cd/g xerogel were obtained for ChM and ChF, respectively. The studied composites are considered promising adsorbent materials for removing cadmium ions from aqueous systems.

Rapid, Selective, and Ultra-Sensitive Field Effect Transistor-Based Detection of Escherichia coli.

Escherichia coli (E. coli) was among the first organisms to have its complete genome published (Genome Sequence of E. coli 1997 Science). It is used as a model system in microbiology research. E. coli can cause life-threatening illnesses, particularly in children and the elderly. Possible contamination by the bacteria also results in product recalls, which, alongside the potential danger posed to individuals, can have significant financial consequences. We report the detection of live Escherichia coli (E. coli) in liquid samples using a biosensor based on a field-effect transistor (FET) biosensor with B/N co-coped reduced graphene oxide (rGO) gel (BN-rGO) as the transducer material. The FET was functionalized with antibodies to detect E. coli K12 O-antigens in phosphate-buffered saline (PBS). The biosensor detected the presence of planktonic E. coli bacterial cells within a mere 2 min. The biosensor exhibited a limit of detection (LOD) of 10 cells per sample, which can be extrapolated to a limit of detection at the level of a single cell per sample and a detection range of at least 10-108 CFU/mL. The selectivity of the biosensor for E. coli was demonstrated using Bacillus thuringiensis (B. thuringiensis) as a sample contaminant. We also present a comparison of our functionalized BN-rGO FET biosensor with established detection methods of E. coli k12 bacteria, as well as with state-of-the-art detection mechanisms.

Design of membrane-based microfluidic chip device based on bionic leaf and adsorption detection of tetracycline antibiotics by specific gel membrane

In this study, we developed copper alginate-carbon nanotube/copper sulfide-graphene oxide gel membranes based on the design inspired by the surface structure of leaves and plant transpiration in nature and through the modulation of high-density polymer networks. This light-driven water evaporation-specific adsorption gel membrane is capable of using solar energy to drive water evaporation from contaminated surface water to access tetracycline antibiotics for detection. Combined with the designed biomimetic adsorption detection chip, in situ monitoring of tetracycline antibiotics in water bodies was achieved. Compared with the traditional mass spectrometry detection method, it shows more outstanding performance in terms of time, environmental protection and technology. The microscale adsorption mechanism was further explored on the molecular scale by density functional theory (DFT). The results showed that tetracycline antibiotics were adsorbed on the aerogel membrane mainly through π-πEDA interactions in sandwich (S) configuration and parallel displacement (PD) configuration, which ensured high adsorption efficiency. Under the optimized conditions, the tetracycline concentration detected by the sensor showed a good linear relationship with the cyclic voltammetry curve, and the lowest detection limit was 1.59*10−4 μM. This adsorption detection strategy can reduce the influence of organic matter, inorganic matter, and other classes of antibiotics on the detection of tetracycline antibiotics, and provide a new idea for the high-efficiency photo-thermal actuation and in-situ testing of tetracycline antibiotics.

Effects of Nanoparticles on the Mechanical Properties of the Composites Prepared from Biological and Chemical Gels

Poly (N-isopropyl acrylamide) (PNIPAm) and polyacrylamide (PAAm) are widely used in antifouling research because of their non-harmful nature and their high water-absorbing capacity. In addition, hydrogels such as these two, should be investigated for their mechanical properties because their mechanical properties influence the antifouling paint containing them remaining on the surface of the vessels. In this research PAAm, PNIPAm, and kappa carrageenan (κC) doped with graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) composite gels were examined for their mechanical properties for use in antifouling paints as a potential material. For increasing the mechanical properties of composites, GO and MWCNTs are often used as doping materials. In the research described here, a compressive test was used to determine the elasticity, and the modulus was calculated. The toughness was calculated from the slope of the stress-strain curve. The PAAm, PNIPAm, and κC doped with GO and MWCNT exhibited excellent swelling and deswelling behavior and good mechanical properties as composites. The results showed that the composites’ mechanical characteristics increased with an ideal loading concentration of GO and MWCNTs. This study was inspired by our belief of a shortage of research on antifouling materials that are sensitive to the environment. We wanted to create materials that were both effective against fouling and environmentally safe by integrating the beneficial characteristics of hydrogels with potential materials inside antifouling paint. This study, we suggest, is an important step toward the development of antifouling materials with high mechanical performance that are also environmentally friendly.

Multi-layer shearing induced high orientation of graphene oxide sheets towards high-performance macrostructures

The orientation of graphene nanosheets in microstructures is directly related to the mechanical properties and thermal conductivity of graphene-based macrostructures. However, efficient and scalable modulation of the orientation of 2D graphene nanosheets remains challenging. Herein, a simple and effective approach was proposed by introducing a multi-layer shearing field in thick graphene oxide (GO) gel coatings to improve the total orientation of GO films. Hydrodynamic simulations were performed via the lattice-Boltzmann method to reveal the microscale mechanism of the flow profile in improving the orientation of GO nanosheets. The result was experimentally verified by fast Fourier transform (FFT) of the cross-section scanning electron microscope (SEM) images of freeze-dried GO films and wide-angle X-ray scattering (WAXS) patterns of 16 various samples under different shearing line distances, velocities, and GO concentrations. The obtained GO films exhibit high orientation (Herman's orientation factor ƒ = 0.922), high strength (419.2 MPa), and high modulus (26.2 GPa), respectively, which are 1.06, 5.57, and 3.49 times higher compared to GO films prepared through the frequently used doctor blade method. The good orientation of GO is remained and further improved to the ultra-high orientation (ƒ = 0.968) after being graphitized at 3150 °C and roll pressing, and the oriented thick graphene films achieved the highest thermal conductivity (1629 W m−1 K−1 for 86 μm and 1593 W m−1 K−1 for 110 μm) compared to other graphene films mentioned in the literature as having a similar thickness. The multi-layered shearing strategy represents a facile technology for assembling two-dimensional (2D) nanoscale building blocks into a macroscopic structure with good orientation and high performance.

Sodium alginate/graphene oxide (SA/GO) gel balls for Pb(II)-containing mine wastewater treatment: Molecular design and Pb(II) adsorption characteristics

In view of the difficulty in treating Pb(II)-containing mine wastewater and the low adsorption efficiency of adsorbents, a sodium alginate/graphene oxide (SA/GO) gel ball was designed via molecular simulation using graphene oxide (GO) and sodium alginate (SA) as raw materials and Ca2+ as a crosslinking agent. The morphology and structure of the prepared SA/GO gel spheres were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD), and their Pb(II) adsorption properties were studied. Molecular simulation studies showed that strong hydrogen bonding occurs between SA/GO and Ca2+. At a CaCl2 concentration of 5 wt%, the shear modulus reached 2.4199, indicating that the SA/GO gel balls had good mechanical strength. An SA/GO gel ball was prepared based on the optimal formula. The adsorption exploration experiment showed that when the temperature was 35 °C, the dosage of the gel ball was 0.02 g, and the adsorption time was 24 h, it had good adsorption performance. Isothermal adsorption analysis showed that at 25,35, and 45 °C, the equilibrium adsorption capacities are 418.41 mg/g, 366.30 mg/g, and 400.00 mg/g, respectively and Pb(II) adsorption using the SA/GO gel balls followed the Langmuir isothermal model, and the adsorption kinetics were quasi-second-order. XPS and EDS studies shown that Pb(II) was successfully adsorbed through complexation, ion exchange and hydroxy-carboxyl functional group reaction. The recovery experiment showed that after four adsorption cycles, the adsorption capacity of SA/GO decreased from 202.56 mg/g to 188.65 mg/g, indicating that SA/GO has a certain degree of recyclability.

Immunological Response to Subcutaneous and Intranasal Administration of SARS-CoV-2 Spike Protein in Mice.

In novel coronavirus infection (COVID-19), the outbreak of acute lung injury due to trans-airway infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the starting point of severe disease. The COVID-19 pandemic highlights the need for a vaccine that prevents not only the disease but also its infection. Currently, the SARS-CoV-2 vaccine is administered via intramuscular injection and is generally not immunogenic to the mucosa. As a result, current vaccinations fail to reduce viral shedding and transmission and ultimately do not prevent infection. We established a mouse vaccine model in which a single dose of S1 protein and aluminum oxide gel (alum) subcutaneous vaccine was followed by a booster dose of S1 protein and CpG oligodeoxynucleotide intranasal vaccine. The group that received two doses of the intranasal vaccine booster showed a significant increase in IgG and IgA antibody titers against S1 and RBD in serum and BAL, and a significant difference in neutralizing antibody titers, particularly in BAL. One intranasal vaccine booster did not induce sufficient immunity, and the vaccine strategy with two booster intranasal doses produced systemic neutralizing antibodies and mucus-neutralizing antibodies against SARS-CoV-2. It will be an important tool against the emergence of new viruses and the next pandemic.

Swell-shrink and microstructural response of expansive soil treated with nanomaterials

ABSTRACT Expansive soils like Black Cotton Soil, exhibit numerous engineering hurdles due to their high swell-shrink behaviour, resulting in structural instability. Traditional stabilization techniques often prove inadequate and available nanomaterials are expensive, creating a demand for a cost-effective and eco-friendly stabilizer like nano rice husk ash (nRHA). This study tackles the challenge of stabilizing expansive soil using nRHA, synthesized via two distinct ball milling methods. Various concentrations of nRHA (0%, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%) were tested to assess their effectiveness in reducing the swell-shrink behaviour of Black Cotton Soil.r Result indicate that a 0.4% dosage of 2 + 5 hours nRHA (n 2,0.4) significantly decreases the soil’s swell-shrink potential. This treatment triggers the formation of Calcium Aluminium Oxide (CAO) and Calcium Aluminium Silicate Hydrate (CASH) gels, validated by X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis. This study advances nRHA treatments in enhancing the swell-shrink behaviour of expansive Soil.

Zeolite Imidazolate Frameworks-8@SiO2-ZrO2 Crystal-Amorphous Hybrid Core-Shell Structure as a Building Block for Water Purification Membranes.

Metal-organic frameworks (MOFs) are emerging as promising materials for water purification membranes, owing to their uniform microporous structures and chemical functionalities. Here, we report a simple procedure for depositing MOF-based nanofiltration membranes on commercial TiO2 ceramic tubular supports, completely avoiding the use of dispersants or binders. Zeolite imidazolate frameworks-8 (ZIF-8) nanocrystals were synthesized in methanol at room temperature and subsequently coated with an amorphous SiO2-ZrO2 gel to generate a dispersion of ZIF-8@SiO2-ZrO2 core-shell nanoparticles. The amorphous SiO2-ZrO2 gel served as a binding agent for the ZIF-8 nanocrystals, thus forming a defect-free continuous membrane layer. After repeating the coating twice, the active layer had a thickness of 0.96 μm, presenting a rejection rate >90% for the total organic carbon in an aquaculture effluent and in a wastewater treatment plant, while reducing the concentration of trimethoprim, here used as a target pollutant. Moreover, the oxide gel provided the MOF-based active layer with good adhesion to the support and enhanced its hydrophilicity, resulting in a membrane with excellent mechanical stability and resistance to fouling during the crossflow filtration of the real wastewater samples. These results implied the high potential of the MOF-based nanocomposite membrane for effective treatment of actual wastewater streams.

Mechanically robust and highly electrochemical performance of polyethylene oxide gel polymer electrolyte

AbstractSynthesizing high‐performance of gel polymer electrolytes (GPEs) with simple methods and common materials has long been a crucial concern for lithium‐ion batteries. Here, the poor mechanical properties of polyethylene oxide (PEO) based GPEs were overcome by introducing strong hydrogen bond between PEO and polyacrylic acid (PAA). Easy‐available PEO/PAA membranes were prepared though hot processing approach without use of organic solvent during all processes. The mechanical properties and crystalline of dry composites could be tuned by the addition content of PAA. After quick absorbing electrolyte in 30 min, the tensile strength and elongation at break of the GPEs composites are ranged from 0.07 to 0.63 MPa, and 525% to 722%. Moreover, the lithium‐ion conductivity and transference number with 30 wt% addition of PAA reach up to 1.66 and 0.58 mS/cm, respectively. After 500 cycling at 0.5 C, the discharge specific capacity and the capacity retention rate are still up to 134.1 mAh/g and 88.7%, respectively. This research proves the great possibility of applying environmentally friendly method, low cost, and high electrochemical performances of PEO/PAA based GPEs in the lithium batteries.

Dark and sunlight-driven dye degradation over a TiO2–dibenzoylmethane hybrid xerogel

The pursuit of sustainable and inexpensive systems for the degradation of organic aquatic pollutants working under sunlight or even without irradiation is still open. Herein, an amorphous titanium oxide modified with dibenzoylmethane, an aromatic diketone, is proposed as a solar photocatalyst showing oxidative activity also in the dark. Ti(IV)-dibenzoylmethanate (dbm) complexes form during the sol-gel synthesis and are dispersed throughout the oxide gel structure. This ligand-to-metal charge transfer complex plays a dual role: it enables visible light absorption, narrowing the apparent band gap, and provides localized surface charge, promoting the spontaneous formation and stabilization of superoxide radical ions by reduction of O2. The activity of the TiO2-dbm hybrid was assessed in the removal of methylene blue from aqueous solution. The results demonstrated a rather stable photocatalytic activity under natural sunlight, exceeding 80% dye removal after 1 h in four subsequent tests, a value that was mostly recovered after a mild regeneration. Considerable efficiencies were also achieved in the dark, owing to the immobilized superoxide radicals acting as initiators of degradation pathways. Finally, the influence of the operating conditions (pH, illumination, mixing method, water contact) on the efficiency and durability of the performances was evaluated to survey the long-term utilization in water decontamination. The behaviour of this hybrid material resembles a “photocatalytic memory” effect and may widen the perspectives for the development of heterogeneous advanced oxidation processes.

Performance analysis of GO gel composite coating on electro-spark deposited surfaces

The uneven surface roughness observed in the electro-spark deposition (ESD) process can be attributed to the unsteady pulsed electrical energy. ESD coating frequently needs to be processed in order to achieve higher surface quality. The surface of the coating undergoes processing techniques such as grinding, ultrasonic processing, and rolling. Because some coatings are hard and the surface hardness is uneven, surface processing is complicated. When a grinder is used for processing, the coating thickness is not easy to control. The product performance is uneven. When non-metallic coatings are used, it can enhance the surface quality of the coating. This study used a composite coating of sodium silicate and lubricating particles. Three coating schemes were studied. Graphene oxide (GO) gel and sodium silicate composite coating have the best overall performance. It can effectively improve the surface quality of the coating, with less roughness and better wear resistance. Graphene oxide gel is used to solve the problem of lubricating particle agglomeration. When it was actually applied to the SKH51 layer, the surface roughness Ra was reduced from 1.086µm to 0.113µm. It is effective in reducing friction and wear.

Nb2O5-graphene heterojunction composite with ultrahigh photocatalytic activity for solar light driven photodegradation of ciprofloxacin

Poor visible light absorption capacity and intrinsic conductivity restrict many applications of Nb2O5 in photocatalysis. The paper describes one solution for synthesizing Nb2O5-graphene photocatalyst with functional graphene quantum dot (GQD). Firstly, Nb(V) was coordinated with GQD to form water-soluble complex. Then, it was bound to graphene sheet via π-π stacking, reduced with ascorbic acid to produce graphene oxide gel and annealed in N2 at 900 °C. The resultant Nb2O5 nanocrystals offer ultrasmall size of 8.8 ± 0.6 nm and good crystallinity. The introduction of GQD realizes the construction of heterojunction. This narrows bandgap energy of Nb2O5 and optimizes the band structure. The narrowed bandgap energy leads to an enhanced visible light absorption, and more negative conduction band potential and more positive valence band potential promote production of superoxide (•O2–) and hydroxyl radicals (•OH). Combination of graphene with GQD improves adsorption of ciprofloxacin, separation of generated electrons and holes and light absorption capacity. G-Nb2O5-900 exhibits an excellent photocatalytic performance for solar light driven photodegradation of ciprofloxacin. The photodegradation efficiency is more than 3.58 times under ultraviolet light radiation and 12.4 times under visible light radiation over pristine Nb2O5. G-Nb2O5-900 shows a broad application prospect in antibiotic treatment in environmental water.

Nano transdermal system combining mitochondria-targeting cerium oxide nanoparticles with all-trans retinoic acid for psoriasis

Psoriasis is an inflammatory skin disease that is intricately linked to oxidative stress. Antioxidation and inhibition of abnormal proliferation of keratinocytes are pivotal strategies for psoriasis. Delivering drugs with these effects to the site of skin lesions is a challenge that needs to be solved. Herein, we reported a nanotransdermal delivery system composed of all-trans retinoic acid (TRA), triphenylphosphine (TPP)-modified cerium oxide (CeO2) nanoparticles, flexible nanoliposomes and gels (TCeO2-TRA-FNL-Gel). The results revealed that TCeO2 synthesized by the anti-micelle method, with a size of approximately 5 nm, possessed excellent mitochondrial targeting ability and valence conversion capability related to scavenging reactive oxygen species (ROS). TCeO2-TRA-FNL prepared by the film dispersion method, with a size of approximately 70 nm, showed high drug encapsulation efficiency (>96%). TCeO2-TRA-FNL-Gel further showed sustained drug release behaviors, great transdermal permeation ability, and greater skin retention than the free TRA. The results of in vitro EGF-induced and H2O2-induced models suggested that TCeO2-TRA-FNL effectively reduced the level of inflammation and alleviated oxidative stress in HaCat cells. The results of in vivo imiquimod (IMQ)-induced model indicated that TCeO2-TRA-FNL-Gel could greatly alleviate the psoriasis symptoms. In summary, the transdermal drug delivery system designed in this study has shown excellent therapeutic effects on psoriasis and is prospective for the safe and accurate therapy of psoriasis.

Semi-solid extrusion 3D-printing of eucalypt extract-loaded polyethylene oxide gels intended for pharmaceutical applications

In pharmaceutics, 3D printing is considered as a promising future technology for fabricating more complex patient-specific drug delivery systems (DDSs). An anti-staphylococcal herbal preparation, “Chlorophyllipt”, is produced mainly in a liquid form by the pharmaceutical industry in Ukraine, and it is composed of an ethanolic eucalypt extract (EE). Since staphylococcal infections have become a true challenge for the health care in all over the world, it would be relevant and justified to develop the aqueous gels of the present EE applicable for the 3D printing of the corresponding solid DDSs. The aim of the present study was to develop a novel polyethylene oxide (PEO) gel loaded with EE for a semi-solid extrusion (SSE) 3D printing and to print the corresponding oral solid DDSs with different sizes and shapes. For SSE 3D printing, we prepared and tested total ten (10) different aqueous PEO gel formulations loaded with EE. Prior to 3D printing, the physical appearance, homogeneity, injection force and viscosity of the gels were investigated. The EE-PEO gels were printed to lattice- and round-shaped solid DDSs with the head speed of 0.5 mm/s, and the weight (mass uniformity) and effective surface area of the printed systems were determined. The most feasible EE-PEO gel for SSE 3D printing comprised of 10 mg/ml of EE, 30 mg/ml of eumulgin and 20 mg/ml of ascorbic acid in a 20-% aqueous PEO gel. The key process parameters of the SSE 3D printing were identified and verified. The printing quality of EE-PEO DDSs were very good, thus showing compatibility of a plant extract and carrier polymer. Such 3D-printed antimicrobial DDSs can be used for example in the treatment of skin wounds and infections of the oral cavity.

Electrochemical Response of 3D-Printed Free-Standing Reduced Graphene Oxide Electrode for Sodium Ion Batteries Using a Three-Electrode Glass Cell.

Graphene and its derivatives have been widely used to develop novel materials with applications in energy storage. Among them, reduced graphene oxide has shown great potential for more efficient storage of Na ions and is a current target in the design of electrodes for environmentally friendly Na ion batteries. The search for more sustainable and versatile manufacturing processes also motivates research into additive manufacturing electrodes. Here, the electrochemical responses of porous 3D-printed free-standing log-type structures fabricated using direct ink writing (DIW) with a graphene oxide (GO) gel ink are investigated after thermal reduction in a three-electrode cell configuration. The structures delivered capacities in the range of 50-80 mAh g-1 and showed high stability for more than 100 cycles. The reaction with the electrolyte/solvent system, which caused an initial capacity drop, was evidenced by the nucleation of various Na carbonates and Na2O. The incorporation of Na into the filaments of the structure was verified with transmission electron microscopy and Raman spectroscopy. This work is a proof of concept that structured reduced GO electrodes for Na ion batteries can be achieved from a simple, aqueous GO ink through DIW and that there is scope for improving their performance and capacity.

Carbon-Coated MnO Quantum Dot-Decorated Three-Dimensional Graphene Aerogel Composite for High-Performance Lithium-Ion Batteries

Herein, carbon-coated MnO QDs decorated on a graphene aerogel (GA, C@MnO QDs/GA) were fabricated by forming a manganese oxide gel in situ on the GA, followed by supercritical drying and carbonization. The composite combines the uniform distribution of ultra-small MnO QDs and the conducting GA with the 3D porous interconnected network structure. The well-dispersed tiny MnO quantum dots can buffer the volume change and shorten the ion diffusion path to improve the reaction kinetics. The GA can provide a 3D conductive channel for rapid electron transfer and Li+ diffusion. When used as anodes for Li-ion batteries, C@MnO QDs/GA electrodes displayed superior electrochemical performance, such as ultra-high discharge capacity, excellent cycling stability, and outstanding rate performance. A high discharge capacity of 1698 mA h g–1 was delivered after 100 cycles at 200 mA g–1, and a capacity of 702 mA h g–1 can be retained at a high current density of 2000 mA g–1. The results suggest that the C@MnO QDs/GA materials designed in this work can be potential anodes for high-performance LIBs, providing meaningful implications for further exploration of oxide anodes for next-generation alkali metal-ion batteries.

Efficient adsorption of arsenic in groundwater by hydrated iron oxide and ferromanganese oxide chitosan gel beads

To address the arsenic contamination in groundwater, the hydrated iron oxide gel beads (CS-HFO) and iron manganese oxide gel beads (CS-FMO) adsorbents were prepared. The CS-HFO and CS-FMO adsorbents had porous and adsorption-friendly pore structures inside, with the average pore sizes of 3.45 nm and 7.78 nm, respectively. As compared to the CS-HFO adsorbent, the CS-FMO adsorbent had rich adsorption sites and oxidation capacity and displayed better adsorption performance. According to the Langmuir model, the saturation adsorption of As(V) and As(III) for CS-FMO adsorbent was calculated as 26.65 mg/g and 35.96 mg/g, respectively. After 10 cycles of regeneration, the CS-HFO and CS-FMO adsorbents demonstrated excellent sustainable arsenic removal ability, while the adsorption efficiencies of CS-FMO adsorbent for As(V) and As(III) were maintained over 60 % and 95 %, respectively. In addition, the competing pollutants and fixed-bed column experiments confirmed the high selectivity of the CS-HFO and CS-FMO adsorbents, which showed great promise for the future application of arsenic contamination removal from the actual groundwater environment.

A Cellulose/Polyethylene Oxide Gel Polymer Electrolyte with Enhanced Mechanical Strength and High Ionic Conductivity for Lithium‐Ion Batteries

AbstractPolyethylene oxide (PEO) gel polymer electrolyte (GPE) is a promising electrolyte for rechargeable lithium‐ion batteries (LIBs). However, they still suffer from weak mechanical properties and low ionic conductivity. Herein, a novel hybrid GPE with enhanced mechanical properties and superior ionic conductivity is developed by introducing regenerated cellulose (RC) into PEO. Benefiting from the 3D porous interconnected network structure of cellulose aerogels, the obtained PEO‐RC GPEs exhibit improved mechanical strength (up to 40 MPa), increased electrolyte absorption ability, excellent ionic conductivity (4.34 × 10−3 S cm−1), and remarkable Li‐ion transfer number (0.60). As a result, a rechargeable LIB assembled with LiFePO4/GPEs/Li demonstrates a high initial discharge capacity of 149.3 mAh g−1 at 0.2 C and an impressive capacity of 141.3 mAh g−1 (94.6% capacity retention) after 100 cycles. This work provides a new route to the design and synthesis of novel GPEs toward next‐generation safe rechargeable LIBs.

Crystalline Magnetic Gels and Aerogels Combining Large Surface Areas and Magnetic Moments.

The production of materials that simultaneously combine large surface areas and high crystallinities is a major challenge. Conventional sol-gel chemistry strategies to produce high-surface-area gels and aerogels generally result in amorphous or poorly crystalline materials. To attain proper crystallinities, materials are exposed to relatively high annealing temperatures that result in significant surface losses. This is a particularly limiting issue in the production of high-surface-area magnetic aerogels owing to the strong relationship between crystallinity and magnetic moment. To overcome this limitation, we demonstrate here the gelation of preformed magnetic crystalline nanodomains to produce magnetic aerogels with high surface area, crystallinity, and magnetic moment. To exemplify this strategy, we use colloidal maghemite nanocrystals as gel building blocks and an epoxide group as the gelation agent. After drying from supercritical CO2, aerogels show surface areas close to 200 m2 g-1 and a well-defined maghemite crystal structure that provides saturation magnetizations close to 60 emu g-1. For comparison, the gelation of hydrated iron chloride with propylene oxide provides amorphous iron oxide gels with slightly larger surface areas, 225 m2 g-1, but very low magnetization, below 2 emu g-1. Thermal treatment at 400 °C is necessary to crystallize the material, which results in a surface area loss down to 87 m2 g-1, well below the values obtained from the nanocrystal building blocks.