Review on current development of polybenzimidazole membrane for lithium battery

With the rapid development of portable technology,lithium batteries have emerged as potential candidates for high-performance energy storage systems owing to their high energy density and cycling stability.Among the key components of a lithium battery system,the separator plays a critical role as it directly influences the battery performance benchmark(cycling performance and safety).However,traditional polyolefin separators(polypropylene/polyethylene)are unable to meet the demands of highperformance and safer battery systems due to their poor electrolyte compatibility,thermal runaways,and ultimate growth of dendrites.In contrast,membranes fabricated using polybenzimidazole(PBI)exhibit excellent electrolyte wettability and outstanding thermal dimensional stability,thus holding great potential as separators for high-performance and high-safety batteries.In this paper,we present a comprehensive review of the general requirements for separators,synthesis technology for separators,and research trends focusing PBI membranes in lithium batteries to alleviate the current commercial challenges faced by conventional polyolefin separators.In addition,we discuss the future development direction for PBI battery separators by considering various factors such as production cost,ecological footprint,preparation technology,and battery component compatibility.By exploring these perspectives,we aim to promote the continued application and exploration of PBI-based materials to advance lithium battery technology.

Preparation of Cellulose Acetate Butyrate Porous Micro/Nanofibrous Membranes and Their Properties

Cellulose acetate butyrate(CAB)is a cellulose ester that is commonly used in applications such as coatings and leather brighteners.However,its appearance in a fibrous form is rarely reported.CAB porous micro/nanofibrous membranes with a large number of nanopores on the fiber surface were successfully prepared by electrospinning with dichloromethane(DCM)/acetone(AC)as the mixed solvent.Apparent morphology,porosity,moisture permeability,air permeability,static water contact angles,and thermal conductivity of the fibrous membranes were investigated at different spinning voltages.The results showed that with the increase of the spinning voltage,the average fiber diameter of the CAB porous micro/nanofibrous membranes gradually decreased and the fiber diameter distribution was more uniform.When the spinning voltage reached 40 kV,the porosity reached 91.38%,the moisture permeability was up to 7430 g/(m^(2)·d),the air permeability was up to 36.289 mm/s,the static water contact angle was up to 145.0°,while the thermal conductivity of the fibrous membranes reached 0.030 W/(m·K).The material can be applied as thermal-insulation,waterproof and moisture-permeable membranes.

Facile fabrication of durable superhydrophobic fabrics by silicon polyurethane membrane for oil/water separation

Nowadays, oil contamination has become a major reason for water pollution, and presents a global environmental challenge. Although many efforts have been devoted to the fabrication of oil/water separation materials, their practical applications are still hindered by their weak durability, poor chemical tolerance,environmental resistance, and potential negative impact on health and the environment. To overcome these drawbacks, this work offers a facile method to fabricate the eco-friendly and durable oil/water separation membrane fabrics by alkaline hydrolysis and silicon polyurethane coating. The X-ray photoelectron spectroscopy, scanning electron microscopy, and atomic force microscopy results demonstrate that silicon polyurethane membrane could be coated onto the surface of hydrolyzed polyester fabric and form a micro-/nano-scaled hierarchical structure. Based on this, the modified fabric could have a stable superhydrophobic property with a water contact angle higher than 150°, even after repeated washing and mechanical abrasion 800 times, as well as chemical corrosion. Moreover, the modified fabrics show excellent oil/water separation efficiency of up to 99% for various types of oil–water mixture. Therefore, this durable, eco-friendly and cost-efficient superhydrophobic fabric has great potential in large-scale oil/water separation.

Soft Template-Induced Porous Polyvinylidene Fluoride Membrane for Vanadium Flow Batteries

Vanadium flow batteries(VFBs)are considered ideal for grid-sc ale,long-duration energy storage applications owing to their decoupled output power and storage capacity,high safety,efficiency,and long cycle life.However,the widespread adoption of VFB s is hindered by the use of expensive Nafion membranes.Herein,we report a soft template-induced method to develop a porous polyvinylidene fluoride(PVDF)membrane for VFB applications.By incorporating water-soluble and flexible polyethylene glycol(PEG 400)as a soft template,we induced the aggregation of hydrophilic sulfonated poly(ether ether ketone),resulting in phase separation from the hydrophobic PVDF polymer during membrane formation.This process led to the creation of a porous PVDF membrane with controllable morphologies determined by the polyethylene glycol content in the cast solution.The optimized porous PVDF membrane enabled a stable VFB performance for 200 cycles at a current density of 80 mA/cm^(2),and the VFB exhibited a Coulombic efficiency of 95.2%and a voltage efficiency of 87.8%.These findings provide valuable insights for the development of highly stable membranes for VFB applications.

Carbon Capture from Flue Gas Based on the Combination of Non-Contact Hydrophobic Porous Ceramic Membrane and Bubbling Absorption

A hybrid system combined with a non-contact membrane and bubbling absorption is proposed to capture CO_(2) from flue gas.The non-contact way of membrane and liquid absorbent effectively avoids the reduction of gas diffusion flux through the membrane.High-porosity ceramic membranes in hybrid systems are used for gas-solid separation in fuel gas treatment.Due to the high content of H_(2)O and cement dust in the flue gas of the cement plant,the membrane is hydrophobically modified by polytetrafluoroethylene(PTFE)to improve its anti-water,anti-fouling,and self-cleaning performances.The results show that the diffusion flux of CO_(2) through the membrane is still higher than 7.0×10^(−3) mol/m^(2)s(20%CO_(2) concentration)even under the influence of water and cement dust.In addition,slaked lime selected as the absorbent is cheap and the product after bubbling absorption is nano-scale light calcium carbonate.To sum up,the hybrid system combining non-contact membrane and bubbling absorption is expected to be used to capture carbon dioxide from the flue gas of the cement plant.

A new route of fabricating porous polyimide membranes

A novel experimental route to fabricate porous polyimide membranes （PPMs） with ideal air permeability was reported. The polymer solution layer consisting of the corresponding polyamic acid （PAA）, solvent, and dibutyl phthalate （DBP） with a boiling temperature of 340℃ was treated by a simple process. The polymer solution layer was first treated at a lower temperature （about 150℃）, then the received solid membrane was further imidized at a higher temperature （about 270℃）, and finally, DBP was removed from the membrane at a temperature above its boiling temperature. The final asymmetric polyimide membrane with a dense skin layer was obtained. To improve the air permeability of the polyimide membranes, the polymer solution layer was treated between two substrates. And the PPMs with open pores on both sides are fabricated and the air permeability of the films is improved greatly.

A STUDY OF TEARING PROPERTIES OF MEMBRANE COATED FABRICS

In this paper,an equation expressing relationship between trapezoid tear strength and fabrictensile properties,weave texture and geomitry of specimen was studied.It could be used to predicttrapezoid tear strength for uncoated fabrics well,and also for coated fabrics if multipling a stressconcentration coefficient.The four tear test standard methods(single-rip,double-rip,wing-ripand trapezoid tear)have been adopted to measure the tear strength of fifteen coated fabrics whichwere used for architecture and gencral industrial purposes and the nine corresponding uncoatedfabrics respectively.Analysis and comparison of experimental results showed that there are an ex-cellent correlation between each two methods with the four tear parameters respectively and a goodconsistency of the order of the tear strength for different samples.In addition,the experimental results showed that a good correlation exists between the tenslieproperties and tear strength of coated and uncoated fabrics.

Design and Fabrication of Ceramic Catalytic Membrane Reactors for Green Chemical Engineering Applications

Catalytic membrane reactors(CMRs),which synergistically carry out separations and reactions,are expected to become a green and sustainable technology in chemical engineering.The use of ceramic membranes in CMRs is being widely considered because it permits reactions and separations to be carried out under harsh conditions in terms of both temperature and the chemical environment.This article presents the two most important types of CMRs:those based on dense mixed-conducting membranes for gas separation,and those based on porous ceramic membranes for heterogeneous catalytic processes.New developments in and innovative uses of both types of CMRs over the last decade are presented,along with an overview of our recent work in this field.Membrane reactor design,fabrication,and applications related to energy and environmental areas are highlighted.First,the configuration of membranes and membrane reactors are introduced for each of type of membrane reactor.Next,taking typical catalytic reactions as model systems,the design and optimization of CMRs are illustrated.Finally,challenges and difficulties in the process of industrializing the two types of CMRs are addressed,and a view of the future is outlined.

Meltblown fabric vs nanofiber membrane, which is better for fabricating personal protective equipments

The coronavirus disease 2019(COVID-19)pandemic has led to a great demand on the personal protection products such as reusable masks.As a key raw material for masks,meltblown fabrics play an important role in rejection of aerosols.However,the electrostatic dominated aerosol rejection mechanism of meltblown fabrics prevents the mask from maintaining the desired protective effect after the static charge degradation.Herein,novel reusable masks with high aerosols rejection efficiency were fabricated by the introduction of spider-web bionic nanofiber membrane(nano cobweb-biomimetic membrane).The reuse stability of meltblown and nanofiber membrane mask was separately evaluated by infiltrating water,75%alcohol solution,and exposing under ultraviolet(UV)light.After the water immersion test,the filtration efficiency of meltblown mask was decreased to about 79%,while the nanofiber membrane was maintained at 99%.The same phenomenon could be observed after the 75%alcohol treatment,a high filtration efficiency of 99%was maintained in nanofiber membrane,but obvious negative effect was observed in meltblown mask,which decreased to about 50%.In addition,after long-term expose under UV light,no filtration efficiency decrease was observed in nanofiber membrane,which provide a suitable way to disinfect the potential carried virus.This work successfully achieved the daily disinfection and reuse of masks,which effectively alleviate the shortage of masks during this special period.

POROUS MEMBRANE TEMPLATED SYNTHESIS OF POLYMER PILLARED LAYER

The anodic porous alumina membranes with a definite pore diameter and aspect ratio were used as templates tosynthesize polymer pillared layer structures. The pillared polymer was produced in the template membrane pores, and thelayer on the template surfaces. Rigid cured epoxy resin, polystyrene and soft hydrogel were chosen to confirm themethodology. The pillars were in the form of either tubes or fibers, which were controlled by the alumina membrane pore surface wettability. The structural features were confirmed by scanning electron microscopy results.

PREPARATION OF HIGH DENSITY POLYETHYLENE/POLYETHYLENE-BLOCK-POLY(ETHYLENE GLYCOL)COPOLYMER BLEND POROUS MEMBRANES VIA THERMALLY INDUCED PHASE SEPARATION PROCESS AND THEIR PROPERTIES

High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.

Porous polybenzimidazole membranes with positive charges enable an excellent anti-fouling ability for vanadium-methylene blue flow battery

A cost-effective, high-performance and highly stable membrane has always been in intensively needed in aqueous organic-based flow batteries. Here we present a porous polybenzimidazole(PBI) membrane with positive charges that endow the membrane with a high rejection and an excellent anti-fouling ability for target organic molecule and asymmetric structure that affords a high conductivity for vanadiummethylene blue flow battery(V-MB FB). The morphologies and thickness of separating layer in particular of the porous PBI can be well adjusted by simply altering the polymer concentration in the cast solution and further afford the membrane with a controllable property in terms of both ion selectivity and ion conductivity. As a result, a V-MB FB assembled with a porous PBI membrane delivers a coulombic efficiency(CE) of 99.45% and an energy efficiency(EE) of 86.10% at a current density of 40 mA cm^(-2), which is 12% higher than that afforded by a Nafion 212 membrane. Most importantly, the V-MB FB demonstrates a methylene blue(MB) utilization of 97.55% at a theoretical capacity of 32.16 Ah L^(-1)(based on the concentration of MB in the electrolyte) because of the high ion conductivity of the membrane, which favors reducing the cost of a battery. The results suggest that the designed porous PBI membranes exhibit a very promising prospect for methylene blue-vanadium flow battery.

Nanotube Arrays in Porous Anodic Alumina Membranes

This review summarizes the various techniques developed for fabricating nanotube arrays in porous anodic alumina membranes （AAMs）. After a brief introduction to the fabrication process of AAMs, taking carbons, metals, semiconductors, organics, biomoleculars, and heterojunctions as typical examples, attention will be focused on the recently established methods to fabricate nanotubes in AAM, including electrochemical deposition, surface sol-gel, modified chemical vapor deposition, atomic layer deposition, and layer-by-layer growth. Every method is demonstrated by one or two reported results. Finally, this review is concluded with some perspectives on the research directions and focuses on the AAM-based nanotubes fields.

Porous catalytic membranes for CO_(2)conversion

Catalytic CO_(2)conversion has witnessed a dynamic growth in recent decades.Various materials have been applied to reduce CO_(2)into fuels and value-added chemicals.Normally,the powder-based catalysts cannot be directly utilized for CO_(2)conversion.Much attention was paid to the study of catalytic membranes in order to overcome this issue,since it is convenient for catalytic membranes to be employed in devices for practical applications.In this review,the recent research development of porous catalytic membranes for CO_(2)conversion is summarized.The preparations of representative porous catalytic membranes and their CO_(2)conversion methods,including electrocatalysis,photocatalysis,photoelectrocatalysis,thermalcatalysis and biocatalysis,are discussed in detail.This review is expected to provide deep understanding on the utilization of porous catalytic membranes for CO_(2)conversion.

HYDROPHILIC MODIFICATION OF PPESK POROUS MEMBRANES VIA AQUEOUS SURFACE-INITIATED ATOM TRANSFER RADICAL POLYMERIZATION

Hydrophilic surface modification of poly(phthalazinone ether sulfone ketone)(PPESK) porous membranes was achieved via surface-initiated atom transfer radical polymerization(ATRP) in aqueous medium.Prior to ATRP.chloromethyl groups were introduced onto PPESK main chains by chloromethylation.Chloromethvlated PPESK(CMPPESK) was fabricated into porous membrane through phase inversion technique.Hydrophilic poly(poly(ethylene glycol) methyl ether methacrylate)(P(PEGMA)) brushes were grafted from CMPPESK membrane ...

Membrane finite element method for simulating fluid flow in porous medium

A new membrane finite element method for modeling fluid flow in a porous medium is presented in order to quickly and accurately simulate the geo-membrane fabric used in civil engineering. It is based on discontinuous finite element theory, and can be easily coupled with the normal Galerkin finite element method. Based on the saturated seepage equation, the element coefficient matrix of the membrane element method is derived, and a geometric transform relation for the membrane element between a global coordinate system and a local coordinate system is obtained. A method for the determination of the fluid flux conductivity of the membrane element is presented. This method provides a basis for determining discontinuous parameters in discontinuous finite element theory. An anti-seepage problem regarding the foundation of a building is analyzed by coupling the membrane finite element method with the normal Galerkin finite element method. The analysis results demonstrate the utility and superiority of the membrane finite element method in fluid flow analysis of a porous medium.

Preparation of YSZ Microporous Membranes on Porous α-Alumina with Metal chlorides as Precursor

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A Diffusion Equation for Gas Permeation though an Inorganic Porous Membrane in the Knudsen Regime

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Demulsification of Water in oil Emulsion by Using Porous Glass Membrane

The hydrophilic porous glass membranes were used to demulsify water in oil emulsion, liquid membrane and demulsification efficiency can reach more than 96 percent. Effects of pore size of the membrane, transmembrane pressure and volumetric ratio of oil phase to internal aqueous phase in the emulsion on demulsification were investigated. Correspondingly, effect of transmembrane pressure on permeation flux of the droplets was also studied.

Harvesting Microalgae Biomass Using Sulfonated Polyethersulfone(SPES)/PES Porous Membranes in Forward Osmosis Processes

This study was performed to investigate the availability of forward osmosis(FO)for microalgae harvesting using sulfonated polyethersulfone(SPES)/PES porous membranes.In FO process,porous membranes(<25.0 L m^−2 h^−1)exhibited more superior water flux than TFC FO membranes(<2.6 L m^−2 h^−1).Furthermore,the incorporation of SPES has been demonstrated to enhance membrane performance.The effects of SPES content on pore structure and separation performance were investigated.Compared with pure PES porous membranes,porous membranes with 40%SPES yielded an improved hydrophilicity and greater porosity.It exhibited two times higher water fluxes than the pure PES porous membrane.For microalgae harvesting,AL-FS mode(active layer facing the feed solution)was more favourable than AL-DS mode(active layer facing the draw solution)because less deposited microalgae on the active layer mitigate the membrane biofouling.FO operation combined with SPES/PES porous membranes is conducive to preserving microalgae cell integrity under the mild condition.In addition,FO membrane can be cleaned by a simple water rinse.Potential implications were highlighted as a sustainable method for microalgae harvesting because of no pressure input and less chemical cleaning demand.