Silica Composite Membranes Research Articles

Preparation of amino-functionalized polyethylene-silica composite membrane and FDH immobilization

Enzymatic CO2 conversion represents a highly efficient, energy-conserving, and environmentally sustainable approach to mitigating the increasing pressure caused by huge carbon emissions and generating valuable products. However, several challenges associate with the process including the instability and recovery difficulty of free enzyme, as well as low solubility of CO2 in mild conditions. Immobilizing enzyme on the amino-functionalized supports presents a viable solution to these issues. Considering the wide application of polymer hollow fiber membranes in the field of CO2 gas–liquid membrane contactor and the characteristics of hydrophilic, biocompatible, and high specific surface area of silica nanoparticles, the amino-functionalized polyethylene (PE)-silica (APS) composite membranes were fabricated via different routes. The morphologies, the loading rates of modified SiO2 and reusability of APS membranes were characterized for a crude screening. Following that, seven kinds of APS membranes were used as the carriers of formate dehydrogenase (FDH) that could catalyze the reduction of CO2 to formate, and their immobilization efficiency and catalytic performance were compared. The results show that 1# and 2# membranes based on carboxyl-modified PE with a loading rate of 5.5 %∼5.6 % and the reusability of above 99 % were more ideal carriers than others. The enzyme activity recovery rate of APS-immobilized FDH (FDH-APS) was separately 367 % and 256 %, proving the intensification action of carriers on the enzymatic reaction. After 10 cycles of use, the relative activity of two kinds of FDH-APS was around 70 % and 78 %, much higher than corresponding particles or membrane attached FDH (25.3 % and 20.4 %). After storage at 4 °C for 20 days, the relative activity of FDH-APS was 82.7 % and 81.0 %, while it was only 61.4 % for free enzyme.

PDMS‐silica composite gas separation membranes by direct ink writing

AbstractPolydimethylsiloxane (PDMS)‐based membranes containing amine‐functionalized and unfunctionalized silica particles were fabricated via direct ink writing for CO2/N2 gas separation. The printability of the inks was evaluated by rheological measurements, while spectroscopy, microscopy, thermal measurements, and mechanical testing were employed to characterize the printed membranes. The surface morphology of the membranes revealed the absence of voids, demonstrating their suitability for gas separation. The printed membranes also exhibited desirable thermal and mechanical properties (i.e., thermal degradation temperature of 518 °C and tensile strength as high as 1.178 MPa with 529% elongation). The PDMS‐based membranes generally displayed high permeability for CO2 but slightly low selectivity for the CO2/N2 gas pair. The best‐combined permeability‐selectivity performance of 8794 barrer and selectivity of 11.64 was demonstrated by the printed PDMS membrane containing no SiO2 fillers. The inclusion of unfunctionalized SiO2 particles generally increased the membrane's gas permeability but compromised the selectivity. In contrast, membranes with amine‐functionalized silica showed improved selectivity compared to membranes containing unfunctionalized silica. Overall, the performance and characteristics offered by the PDMS/silica composite membranes demonstrated the potential of 3D printing as an economical and sustainable fabrication approach to developing materials for carbon capture applications.

Composite membranes of cellulose–mesoporous silica: optimization of membrane fabrication and adsorption capacity

In this work, we produced composites of mesoporous silica synthesized in-situ on never-dried bleached eucalyptus kraft pulp fibers with the aim of providing cost-effective depth filters, having high flux, and adsorptivity. The mesoporous silica loading for the produced samples was in the range of 12–35 wt%. The performance of double-layer membranes was studied for the adsorption of charged molecules. The best nanofibrillated cellulose-pulp-mesoporous silica membrane adsorbed 1160 mg/m2 of methylene blue and had a flux of 10 L m−2 h−1 bar−1. The nanofibrillated cellulose layer supported the pulp-mesoporous silica layer and improved the adsorptivity of the pulp-mesoporous silica depth filter layer by controlling flux. The membranes showed non-linear-pseudo-first-order adsorption kinetics and non-linear Freundlich isotherm for methylene blue adsorption. The nanofibrillated cellulose-pulp-mesoporous silica membrane was modified for metanil yellow adsorption by adding polyamide amine-epichlorohydrin resin. The best metanil yellow saturated adsorption capacity was 9400 mg/m2. The nanofibrillated cellulose-pulp-mesoporous silica depth filter without modification with a polyelectrolyte also had 92% and 94% heavy metal removal of 20 mg of Cu2+ and Pb2+ ions, respectively. The novel pulp-mesoporous silica composite membrane, with high adsorption capacity and manufactured by lower embodied energy of cellulose fiber, can significantly lower large-scale depth filter production costs due to the elimination of cellulose pre-treatment for the depth filter layer. The reusability performance in the fifth cycle, after four cycles of metanil yellow adsorption and desorption, was 5.2 mg/g, which was stabilized from the 3rd to 5th cycles. This suggests the suitability of these membranes for industrial applications.

Analysis of Ionic Domain Evolution on a Nafion-Sulfonated Silica Composite Membrane Using a Numerical Approximation Model Based on Electrostatic Force Microscopy.

It is important to characterize the proton transport mechanisms of proton exchange membranes (PEMs). Electrostatic force microscopy (EFM) is used to characterize the ionic structures of membranes. In this study, we attempted to quantitatively analyze the proton conductivity enhancement of Nafion-sulfonated silica (SSA) composite membranes with variations in the ionic channel distribution. This study involved several steps. The morphology and surface charge distribution of both membranes were measured using EFM. The measured data were analyzed using a numerical approximation model (NAM) that was capable of providing the magnitude and classification of the surface charges. There were several findings of ionic channel distribution variations in Nafion-SSA. First, the mean local ionic channel density of Nafion-SSA was twice as large as that of the pristine Nafion. The local ionic channel density was non-uniform and the distribution of the ionic channel density of Nafion-SSA was 23.5 times larger than that of pristine Nafion. Second, local agglomerations due to SSA were presumed by using the NAM, appearing in approximately 10% of the scanned area. These findings are meaningful in characterizing the proton conductivity of PEMs and imply that the NAM is a suitable tool for the quantitative assessment of PEMs.

Comparison of hydrogen permeation and structural properties of a microporous silica membrane and a dense BaCe0.9Y0.1O3-δ (BCY) perovskite membrane

Silica composite membranes and BaCe0.9Y0.1O3-δ (BCY) perovskite membranes were successfully synthesized to separate hydrogen in an equimolar mixture of H2, CH4, CO, and CO2 at temperature range of 500–900 °C and pressure difference of 1 bar. The phase structure of both membranes was characterized by X-ray diffraction (XRD). Thermogravimetric analysis (TGA) was used to evaluate phase stability of perovskite membrane. FESEM images confirmed graded structure of silica membrane and uniform, dense structure of perovskite membrane. H2 permeation in semi-dense silica layer deposited on alumina substrate indicated that permeation in top selective layer follows a diffusion mechanism which is based on jumps between solubility sites. On the other hand, low permeation rates of around 10−8 mol m−2 s−1 Pa−1 in perovskite membranes revealed a proton-electron conductivity mechanism which occurs through dense structures. Increasing hydrogen separation factor (SF) in gas mixture by increasing deposition time from 3.5 h to 6 h in silica composite membrane confirms formation of crack-free selective layer; however, this factor is still lower than SF of 0.97–0.99 in perovskite membranes. A set of gas-permeability data is collected at the laboratory scale for the statistical characterization of both membrane types (P01, S01) to provide a dataset from which one can assess statistical scaling features displayed by the data and their scaling increments.

Development of Chitosan/Rice Husk-Based Silica Composite Membranes for Biodiesel Purification.

Inorganic–organic composite membranes (IOCMs) are an alternative separation method developed for their straightforward process, economic benefits, and ease of scaling up. The IOCMs in this study were prepared from a biopolymer chitosan matrix and rice husk-based silica filler to remove impurities from crude biodiesel. The IOCMs were prepared through phase inversions, in which the priorly prepared silica particles were dispersed in the dope solution of chitosan. The maximum loading of the silica particles was 60%, capable of reducing the soap level, free glycerol level, and acid number from 547.9 to 12.2 mg/L, 54 to 0.041%, and 2.02 to 1.12 mgKOH/g. These reduced impurity values have satisfied the standardized quality. The chemical composition and morphology of the IOCM was characterized using Fourier-transform infrared spectroscopy and scanning electron microscope–energy dispersive X-Ray spectroscopy. The IOCM water absorption-based porosity and swelling degree were studied as well. Further investigation using isothermal modeling revealed the adsorption dependency against the Sips model equation (R2 = 0.99 and root-mean-square errors = 1.77 × 10−8). Even though regeneration is still a challenging factor in this study, the IOCM prepared from chitosan and rice husk-derived silica particles could be used in crude biodiesel purification.

Enhancing dehydration performance of isopropanol for flexible hybrid silica composite membranes with spray-coated active layer on polymers

Organically bridged silica has been proven to be promising precursors for fabricating silica-based organic–inorganic hybrid membranes with excellent permselectivity. However, the large-area deposition of defect-free hybrid silica membranes onto the polymer substrate has always been an enormous challenge. Herein, we reported a fast and facile approach for the large-area production of flexible silica-based hybrid membranes, where a thin and uniform ethylene-bridged silica active layer was coated on a microporous polymer substrate via a spray coating process with a single-pass method. First, the optimal deposition conditions were investigated and established, including sol concentrations and different solvent systems that are used to prepare hybrid silica sol, as well as various spray coating conditions. Subsequently, thus-produced flexible hybrid silica composite membranes exhibited superior isopropanol (IPA) dehydration performance by vapor permeation for a 90 wt% isopropanol aqueous solution, with water permeation flux reaching 4.0 kg m-2h−1 and with H2O/IPA separation factor exceeding 1000 (the selectivity of H2O/IPA is 770). This work has shown that the single-pass spray coating is a useful strategy for the large-scale fabrication of the flexible hybrid silica composite membrane.

A Structured Hybrid Catalyst to Improve ORR Activity and Phosphoric Acid in the High-Temperature Exchange Membrane Fuel Cell

The high-temperature proton exchange membrane fuel cell (HT-PEMFC) based on a phosphoric acid (PA)-doped polybenzimidazole (PBI) membrane electrolyte has been attracted attention because of its higher kinetics of oxygen reduction reaction, no flooding issues and excellent carbon monoxide tolerance [1, 2]. However, PA leaching from PBI membrane to electrode is one of the biggest problems as the loss of phosphoric acid causing worse proton conductivity of PBI membrane and preventing gas transfer in the electrode [3]. Furthermore, HT-PEMFC requires higher amount of platinum (Pt) (normally between 0.7 and 1.2 mg cm-2) to provide high electrochemical surface area, which accounts for a higher proportion in the cost of a total fuel cell stack [4]. Therefore, the reduction of phosphoric acid permeation and catalyst dosage are two challenges in HT-PEMFC.Many studies and technologies have been conducted to prevent the permeation of PA. Currently, the modification of PBI membrane structure is the main method by introducing materials with more -NH2 functional groups to form stable chemical bonds with phosphoric acid molecules and prevent their movement [5-7]. However, the composite membrane materials are not uniform and the intercalation of materials (SiO2, Graphene et al) will cause crossover issues to influence the durability of HT-PEMFC [7].Based on our previous research, platinum supported on nitrogen doped reduced electrochemically exfoliated graphene oxide/carbon black hybrid catalysts (Pt/NrEGOx-CBy) have higher oxygen reduction reaction (ORR) activity. This work aims to optimize the ratio of NrEGO and CB in HT-PEMFC and explore the effect of NrEGO flakes on PA permeation to improve the durability of HT-PEMFC. The preliminary results showed that Pt/NrEGO2-CB3 catalyst in a membrane electrode assembly (MEA) had the mass power density of 1.652 W mgPt -1 with a decay rate of 0.01 mV h-1 within 100 hours, which is much lower than that of 1.125 mV h-1 in the commercial Pt/C as shown in Figure 1.Reference[1] J. Lobato, H. Zamora, J. Plaza, P. Cañizares, M.A. Rodrigo. Enhancement of high temperature PEMFC stability using catalysts based on Pt supported on SiC based materials. Applied Catalysis B: Environmental. 2016. 198: 516-524.[2] Y. Hu, Y. Jiang, J.O. Jensen, L.N. Cleemann, Q. Li. Catalyst Evaluation for Oxygen Reduction Reaction in Concentrated Phosphoric Acid at Elevated Temperatures. Journal of Power Sources. 2018. 375: 77-78.[3] G. Liu, H. Zhang, J. Hu, Y. Zhai, D. Xu, Z.-g. Shao. Studies of performance degradation of a high temperature PEMFC based on H3PO4-doped PBI. Journal of Power Sources. 2006. 162 (1): 547-552.[4] H. Su, T.-C. Jao, O. Barron, B.G. Pollet, S. Pasupathi. Low platinum loading for high temperature proton exchange membrane fuel cell developed by ultrasonic spray coating technique. Journal of Power Sources. 2014. 267: 155-159.[5] F. Liu, S. Wang, J. Li, X. Tian, X. Wang, H. Chen, Z. Wang. Polybenzimidazole/ionic-liquid-functional silica composite membranes with improved proton conductivity for high temperature proton exchange membrane fuel cells. Journal of Membrane Science. 2017. 541: 492-499.[6] K.-J. Peng, J.-Y. Lai, Y.-L. Liu. Nanohybrids of graphene oxide chemically-bonded with Nafion: Preparation and application for proton exchange membrane fuel cells, Journal of Membrane Science. 2016. 514: 86-94.[7] C.-L. Lu, C.-P. Chang, Y.-H. Guo, T.-K. Yeh, Y.-C. Su, P.-C. Wang, K.-L. Hsueh, F.-G. Tseng. High-performance and low-leakage phosphoric acid fuel cell with synergic composite membrane stacking of micro glass microfiber and nano PTFE. Renewable Energy. 2019. 134: 982-988. Figure 1

Fabrication of Manganese Oxide-silica Based Functional Polymer Composite Membranes and Their Environmental Application

ABSTRACT Oil-water emulsion separation is a complicated task and recently oil-water spills made it crucial to find a solution to resolve this unfavorable environmental concern. Membrane separation is economical, environmentally safe, and operationally feasible separation process among different methods adopted so far. Keeping this in view neat polysulfone and manganese oxide silica composite membrane were synthesized. The prepared Mn3O4, mesoporous silica, Mn3O4@SiO2, neat and fabricated PSF membranes were thoroughly characterized by X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric, and differential scanning calorimetry, tunneling electron microscopy and scanning electron microscopy. The solvent content, porosity, surface behavior, thermal, and mechanical properties of the membranes were also studied. The increase in the concentration of nanofiller increases the solvent interaction, porosity, thermal stability, and mechanical strength. Amongst all 5 wt.% composite membrane have greater oil/water separation capacity due to greater amount of nanofiller and high porosity. Facile tuning of properties during fabrication process makes these composite membranes a potential candidate to address the oil/water pollution problem of important environmental concern.

Amoxicillin separation from aqueous solution by negatively charged silica composite membrane.

Silica composite membranes were successfully prepared by acid/ base-catalyzed sol-gel method and characterized by SEM, FTIR, AFM and contact angle Low isoelectric point of the silica layers provided negatively charged composite membranes, resulting electrostatic repulsion forces between membrane surface and amoxicillin molecules at higher pHs. The rejection rate of amoxicillin was studied systematically at different pHs, solute concentrations, transmembrane pressures and temperatures. It was found that acid-catalyzed membrane has higher amoxicillin rejection ratio compared to base-catalyzed membrane. Especially, acid-catalyzed membrane achieved the highest rejection of 90% at the transmembrane pressure of 6bar, 45°C, pH = 10, and initial feed concentration of 50ppm. Long term stability exhibit that the membrane performance in permeation flux was steady for up to 100h. However, the AMX rejection of 89% was maintained for over 250h in acid-catalyzed membrane. It was concluded that the use of negatively charged ceramic membranes is promising for removal of amoxicillin from water resources.

Enhancing Dehydration Performance of Isopropanol for Flexible Hybrid Silica Composite Membranes with Spray-Coated Active Layer on Polymers

Enhancing Dehydration Performance of Isopropanol for Flexible Hybrid Silica Composite Membranes with Spray-Coated Active Layer on Polymers

Sulfonated Polyimide–Silica Composite Membranes: Preparation, Morphology and Proton Conductivity

Sulfonated Polyimide–Silica Composite Membranes: Preparation, Morphology and Proton Conductivity

PEI-SiO2 composite membranes with high thermal stability: Synthesis by self-assembled in situ growth and application in lithium-ion batteries

To improve the safety of lithium-ion batteries (LIBs), a polyether amide–silica (PEI-SiO2) composite membrane was developed by the in situ hydrolysis of tetraethylorthosilicate (TEOS) and its subsequent self-assembly on the surface of PEI fibers. Because of the presence of the SiO2 shell, the PEI-SiO2 composite membrane exhibited good thermal stability at high temperatures. The composite membrane did not change its color and size after heating at 200°C for 1 h as well as exhibited excellent flame retardancy. Moreover, the membrane maintained its high porosity even after the introduction of shell layers. The electrolyte is completely absorbed in the membrane within 0.5 s. The electrolyte uptake was up to 625%, and the ionic conductivity was up to 1.9 mS/cm at room temperature. Compared to the polyolefin membrane and the pure PEI membrane, the PEI-SiO2 composite membrane showed higher electrochemical stability, with an electrochemical window of up to 5.5 V. The battery assembled with the composite membrane showed excellent cycle stability, and the capacity retention rate was as high as 98.6% after 50 cycles. The LIBs based on the PEI-SiO2 composite membrane exhibited safe operation and high electrochemical performance, thus highlighting the applicability of the composite membrane in high-power batteries.

Preparation and optimization of antifouling PPSU/PES/SiO2 nanocomposite ultrafiltration membranes by VIPS-NIPS technique

In this paper, the preparation of PPSU/PES/Nano silica composite ultrafiltration membranes by a combined vapor induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) techniques were successfully investigated. For this purpose, the effect of VIPS time from 0 to 60s, the blending ratio of PPSU:PES from 0 to 100%, polymer concentration from 16 to 24wt.%, and SiO2 nanoparticles concentration from 0 to 5wt.% as an additive to dope solution on the performance and characteristics of ultrafiltration membranes were studied. As the number of parameters is high, the response surface methodology (RSM) was applied for designing the experiments for obtaining the optimum condition for the fabrication of a high flux ultrafiltration membrane. Liquid-liquid displacement porosimetry (LLDP), scanning electron microscope (SEM), pure water flux (PWF), and bovine serum albumin (BSA) retention were used for characterization of the fabricated membranes. The results are shown different trends for the effect of SiO2 nanoparticles concentration at the low and high polymer concentrations in dope solution. When the polymer concentration in the dope solution is low, the increase of SiO2 nanoparticles concentration resulted in lower fluxes, but at high polymer concentrations, the increase of the nanoparticles caused an increase in permeate flux. At optimum condition, the highest PWF of 76.65L/m².h (15.33L/m².h.bar), and a BSA retention of 82.01% was obtained.

Preparation and performance of hydrophobic and conductive silica composite fiber membrane

Electrospinning is an important way to prepare fibers. In this paper, hydrophobic and conductive composite fiber membranes were prepared by opposite electrospinning. The hydrophobic material was trimethylethoxysilane, the conductive material was graphene, and polyvinylpyrrolidone was introduced as the carrier material of graphene. It was found that the sol–gel time, the content of silane coupling agent and low-temperature storage of the solution have a certain influence on the hydrophobicity and spinnability of the fiber membrane. At the same time, the effect of graphene content on the spinnability and the electrical conductivity of composite fiber membrane were studied. The results showed that the composite fiber membrane has good hydrophobic properties and electrical conductivity. The water contact angle of the fiber membrane reaches 139.6°, and the conductivity reaches 1972.78 S cm−1.

Separation of Dicyclopentaidene in a C5 stream using a tetraethoxydimethyl disiloxane-derived silica composite membrane

Hybrid separation of dicyclopentadiene (DCPD) in a C5 stream was performed using a 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS)-derived silica composite membrane. High purity DCPD, the key monomer of the C5 stream can be concentrated by removing CPD through pervaporation from the CPD-DCPD mixtures obtained by conventional distillation. Silica membranes were prepared using 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS) by “spacer” and “template” techniques, which allowed for control the pore size of silica membranes using bridged alkoxides that have pendant groups. TEDMDS-derived silica membranes calcined at 450 °C showed a high total flux of 0.06–0.5 kg·m−2 h−1 with a CPD separation factor of 6–33 in a 95 wt% DCPD mixture, for feed temperature of 50–70 °C. The silica membranes prepared in this study shows relatively a high flux and acceptable separation factor. Therefore, they may find applications in commercial processes alongside the conventional distillation, by saving energy and reducing byproducts.

Engineering Sustainable Antimicrobial Release in Silica-Cellulose Membrane with CaCO3-Aided Processing for Wound Dressing Application.

The sustained release of antimicrobial therapeutics for wound dressing has become an attractive design strategy for prolonging the timespan of wound dressings and for reducing the risk of chronic wound infection. Recently, cellulose-based membrane has become a preferred option of wound dressings for the treatment of burn wounds and skin ulcers. In this work, novel cellulose membrane incorporated with mesoporous silica particles (SBA-15) was developed as an antimicrobial wound dressing with desirable sustained release functionality for targeting persistent bacterial pathogens. Attributed to a coated layer of calcium carbonate (CaCO3), SBA-15 particles were free from corrosion in alkaline condition during the preparation of cellulose-based composite membranes. SEM, TEM and BET results showed that the morphology, specific surface area, pore size and pore volume of pristine SBA-15 were preserved after the incorporation of CaCO3-coated SBA-15 into the cellulose matrix, while the mesoporous structure of SBA-15 was significantly disrupted without the use of CaCO3 coating. The resultant composite membranes containing 30 wt% SBA-15 (denoted as CM-Ca2-SBA(30%)) achieved 3.6 wt% of antimicrobial drug loading. Interestingly, CM-Ca2-SBA(30%) demonstrated the sustained release property of chloramphenicol for 270 h, driven by a two-stage drug release processes of SBA-15/cellulose. The water vapor permeability (WVTR) and swelling properties of composite membranes were shown to have complied with the primary requirements of wound dressing. Antibacterial assays revealed that strong antibacterial activities (144 h) of the composite membranes against Staphylococcus aureus and Eschericia coli were achieved. All results displayed that the strategy of coating silica with CaCO3 helps to obtain cellulose–silica composite membranes with desirable sustained release profiles and strong antibacterial activities. The antibacterial SBA-15/cellulose composite membranes show potential for the application of wound dressing.

Studi Performa Membran Hidrofobik Berbasis Silika dalam Proses Pemurnian Biodiesel

Glycerol can cause negative effects on diesel engines such as fuel filter blockage, fouling on fuel injectors and deposit formation at the bottom of the storage tank, it is necessary to do purification to improve the quality of biodiesel in accordance with SNI. Until now, the separation process has been carried out by using a polypropylene hydrophobic polymer membrane. Therefore, another membrane alternative is needed for the refining process of biodiesel production derived from materials that are easy to obtain and of economic value. In this research, the synthesis process of hydrophobic silica composite membrane and the performance of this membrane were carried out in the process of separating FAME with glycerol. This study examines the performance of the hydrophobic silica composite membrane on biodiesel purification for improving the quality of biodiesel resulting from the transesterification process. The results showed that membrane synthesis in this study could produce a hydrophobic membrane with a contact angle above 90 ° (150 °). This hydrophobic membrane can be used in the process of separating CPO-water with a rejection coefficient of 0.99. In addition, from the test results with a flow rate of 3 ml / minute, it was found that this membrane was able to improve the quality of crude biodiesel seen from the parameters of its heating value. In addition, membrane fluxes were 8.1 L / m2.h.

Nafion-sulfonated silica composite membrane for proton exchange membrane fuel cells under operating low humidity condition

Sulfonated silica, synthesized by using tetraethyl orthosilicate and chlorosulfuric acid through calcination, was used as a filler to create Nafion-SSA composite membranes for applying proton exchange membrane fuel cells under low relative humidity (RH) condition. High water uptake and ion exchange capacity values were observed, and the Nafion-SSA composite membrane showed improved proton conductivity than that of the recast Nafion. The fuel cell operating at 80 °C under 20% RH with Nafion-SSA composite membrane showed 2.8 times higher maximum power density (454 mW cm−2) and current density (2062 mA cm−2) in comparison with the recast Nafion (159 mW cm−2, 734 mA cm−2). The thermal stability and mechanical properties of recast Nafion and Nafion-SSA composite membranes were evaluated by TGA and Tensile test.

Covalently‐Bonded Poly(vinyl alcohol)‐Silica Composite Nanofiber Separator with Enhanced Wettability and Thermal Stability for Lithium‐Ion Battery

AbstractCovalently‐bonded poly(vinyl alcohol)‐silica (PVA‐SiO2) composite nanofiber membranes are fabricated via sol‐gel electrospinning and their physical and electrochemical properties are investigated for application as separators in lithium‐ion batteries (LIBs). Experimental results demonstrate the PVA‐SiO2 membranes possess a unique three‐dimensional interconnected porous structure and display higher porosity (73%), better electrolyte affinity, higher electrolyte uptake (405%) and lower thermal shrinkage compared to commercial polypropylene (PP) membranes. In addition, batteries using PVA‐SiO2 composite nanofiber membranes as separators exhibit enhanced ionic conductivity (1.81 mS cm−1), superior cycling stability and C‐rate performance than those using PP separators. These findings reveal that the PVA‐SiO2 composite nanofiber membrane might be a promising alternative to commercial polyolefin separator for high performance LIBs.