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Chapter 4 is about the polymeric separator in battery. Let's talk about the polymeric separator for the ligium in battery. The main role of the separator is to physically separate the anode and the cathode, preventing the direct contact between the dam. This is critical because if the electrical touch were connected, it would cause a short circuit.

and could lead to dangerous safety issues such as overheating or even thermal railway. At the same time, the separator must allow the ion to pass through, like as the lithium ion is passed through, enabling the flow of electrical contact and allowing the battery to operate effectively. So the separator acts as

the selective barrier. It blocked the electron and the direct contact but just permit the redimed ions move freely. So let's talk about the polymer separator slurs. It serves to maintain the physical barrier between the cathode and anode preventing the short circuit. Second, the presence of microphone in the membrane

allow for the passage of the rhythm ions forming the same recharging and discharging circuit. Furthermore, the separator exhibit the ability to shut down in response to appropriate temperatures subsequently caused the microcore, thereby serving as a protective open circuit that safeguard against fire or explosions. So definitely, we already talked about the

physical selective barrier. But for the next generation batteries, their role are a little bit changed. For example electrochemical reactive materials, so coated on this surface and then they is the final of the electrochemical reactive site. So 2 equals battery cycling.

for the Ritum super batteries, one of the critical issues coming from the polysulfide shuttles. At this point, the functional polymer separator can suppress these kinds of the shuttle effect. I guess polysulfide, the Ritum ion is path through, it's selectively, but polysulfide is just go back to the cathode side. In addition,

We can consider the formation of the artificial solid-elect-like interface layer onto the rich metal anode to make the stable battery cycling performance. So let's talk about the general requirement and the characterization of separator using the batteries. The first thing is thickness. The circumvasioners are applied to using the recharge of batteries. Typically,

20 to 50 micrometer thickness. While using relatively thin separator can reduce the internal resistance and render high energy power density. There are several drawbacks to make the mechanical strength and safety. On the other hand, thicker separator provide better mechanical strength. During the battery assembly improving the battery safety.

But there are still thick separator have some the problem of the lithium ion transport So Some overcome the trade-off between the thickness and other battery performance That is the challenge of the battery separator research Second thing is porosity and the porous size is related to the transport The high porosity in the separator is advantageous for an hindered ionic current flow The pore of the separated

are to be uniformly distributed and the minimum size to avoid the deposition of the metallic particles and thus the electronic the bridging is just ionic the pathway is the best options so there are two types of the porosity one is the macroporos so another thing is micro poros so the latter the showing the four diameter below the one micrometer

Thus, the metallic metal the particle deposition, for example, the lithium metals and the sub-tuned shortings is quite low, since axiomotry in storage batteries usually have particle diameters separate from micro. However, even these small pores cannot prevent the formation of so-called micro-short arising through the lithium deposition, such as the lithium dendrite from the solution phase.

The pore size of the recent debugger separator have a diameter of approximately 100 nanometers, while the lithium ions or the other sodium ions or these kinds of metal cations have the diameter of few ohmstrom equal to 0.5 to 1 nanometer. So there is the good for the like as the...

some suppression of the irregular, the ritual depositions, but the problem is the mechanical strength. Third is the chemical stability. The separator material should be chemically stable against the electrode and electrolyte material, especially under strongly oxidative and reductive environment when the battery is fully charged.

Moreover, it should not degradate and lose the mechanical strength. So one of the important things is related to safety. Fourth is about the mechanical strength. So we already know that the mechanical strength of the separator is very important, especially so we measured a lot of the methods to measure the mechanical properties. One of the things is tensile properties.

tensile properties are depending on the manufacturing process. Uniaxial axially oriented films have high strength in only one direction oriented films. While the biaxial oriented films are strong in both transverse and motion directions, though one might expect biaxial the oriental film to be preferred over the uniaxialing

oriented films so the one of the related thing is the sharing quizzes

This shrinks at the at-lipped temperature can allow the electrolytes to contact each other. So to inhibit these kinds of changes at a little bit high temperature is another option for the mechanical strength. Fifth, the wettability of the battery sector separated by the liquid electrolyte is a significant problem, is important properties because when we have the separator,

this kind of liquid electrolyte. The electrolyte absorption is required for the ion transport. To obtain the low internal resistance and high ionic conductivity, separators lose the hole and absorb the considerable amount of the liquid electrolyte. Fast absorption rate facilitated the process of the electrolyte filling during the pastry assembly.

these kinds of the wettability is depending on the type of material and the pore size the porosity related these kinds of things the the right side one is the one of the some the famous the combationer the separator cells are the two three to five so we can see the thickness is 25 micrometer microporos three-way membrane pp

PEPP polypropylene polyethylene polypropylene so we can see a lot of some the information techniques and porosity the GULI value is related to the porosity the thermal the shrinkage or the another shrinkage properties the mechanical property also they can provide in from the this the company so considering these kinds of the spec related to these kinds of things we can find the proper the separator

according to the type of the lithium-ion batteries. Besides the performance and the essential functions of the polymer separators, the separator can be an excellent platform for desired functions, including super-wetability to the electrolyte. And also for boosted ionic diffusions, the stretchable for the flux of battery with thermal resistance, reversible thermal, industrial shutdown,

and also for the lithium metal battery the metal dendrite gold inhibition is also important so extra thing the shuttle effect inhibitions for lithium sulfur batteries is very important whether we can think about the other case we already talked about the transition metal oxide cathode sometimes they can make the the metal cations because of the

corrosive effect from electrolyte battery cycling. If the separator can suppress these kinds of diffusion to the anilocyte, it would be one of the some good option for increasing the battery cycling stability and the rife span. So let's talk about the classification of polymer separator. First thing is a non-oven separator. Non-oven separator or textile.

of the fiber and the most used in the primary and the secondary alkaline batteries. So the usually the this kind of battery that its maximum full size over the 10 micrometer is quite huge and also additionally the thickness of the non-open materials range usually 80 to 300 micrometer thickness. So these kinds of non-open separator are

It has extremely high the porosity, but this high the porosity is good for the ion transport, like as fast the ionic diffusion. So there the ion resistance is lower, but there are some problems, the risk of the electrical shutter circuit. And then second thing, nano porous the membrane. Nano porous the membrane separator has

have 4 in the nanoseximeters. The porosity and thickness of these kinds of separators approximately is 40% and 25 the micrometer thickness. Generally, this type of separator is very homogeneous and containing the inter-penetrating fibrous network structure. The nanoforce property of the separator is quite good point chart.

resistance to transport the battery through the circuit. Additionally, nanoforce memory separator also have a small impedance for the ionic diffusions. Third, its micro force separator have a power in the micrometer, especially PEP, so have the most representative micrometer structure, the separator, and these separators are common in the lithium ion batteries.

Compared to the nanoporous separator, the microporous membrane have significantly improved performance in terms of electrolyte membrane wettability and interfacial adhesion between the separator and the electrode. Ultimately, the bottom steel is very difficult to simultaneously have all ideal characteristics including the mechanical stability, wettability, ion conductivity, thermal resistance, etc. in the micropores.

some structure. So they're using some kinds of the extra materials so we can design the functional polymer separator. So we call the composite separator. So these kinds of things depending on the type of the composite materials so we can design different kinds of things like is increasing the wettability or have high ionic conductivity or improve the mechanical strength.

So using the special material we can design new extra functionality to separate. So we can think about these kinds of four types of separator and which is good for the lithium ions or other type of the battery. So one is the not-woo-moon, the match separator that is the example.

Nanoboon the separator naturally thick 100 to 200 micrometer. But to reduce the thickness the modern the fiber technologies like as centrifugal spinning or like this one electrode spinnings can fabricate fibers is 10 to 20 micrometer thick with the 60 to 80 percent photo cities.

The fibers for this type of separator are manufactured mostly for the textile industry, including cellulose, poliolephine, polygonylchols. The fibers are bonded by friction, cohesions, or adhesion into the seat, web, or mat. Currently, the most commonly used method for making this nanofiber is including electrostatic charge recorded electrospinning techniques,

externally heated energy or fiber spinning by confident things or templates in this or self assembling the method so one of the example they made the electrode spinning the method using the PVP the titanium isopropoxide mixed together and using the electrospeening

They prepare very porous and very thin polymer membranes. And the second thing to improve their properties, they use extra-dobacterial PVTF. Next is Combustionary Separator. We already talked about the micro-porous membranes. The porous membranes based on the TE polyethylene, PP polypropylene are generally utilized as a separator of the lithium-ion batteries.

The development in the manufacturing, these micropores membranes can generally be divided into two steps. One is the wet process, another is dry process. The wet process usually, two companies, the best company, the polymer is developed with a high boiling.

paraffinic solvent that is washed out after biaxial stretchings of the extruded cloth film generate the porous structure. In dry process cell guard one of the vaseline separator the pores are formed entirely due to the constructive monaxial stretchings and annealing the step

of the film acquired from the polymer mat. Throughout the stretchings of the excursuitalized mercury, the crystalline, the paste and the polymer chain are oriented and be formed plastically along the stretching directions. So these kinds of two things we can prepare, the microporous, the membranes. In the modern and next generation lithium-ion batteries, separators are playing an increasingly important role in enhancing the electrochemical performance.

In particular, the development of the next generation battery system with a higher risk density increasingly involves the design, the polymer, the separation of the spatial functionalities. The polymer itself and the polymer separated framework can serve as the excellent carriers and the substrate. Therefore, by modifying the physical or the chemical, the property of the separated desirable functions can be realized.

So we can think about like as the improved the safeties against the fire or the mechanical safety like against the redium dendrite and also for the high battery cycling performance we can think about overcoming the diffusion of the polysulfide shuttles in the lithium super battery moreover for the long-term cycling of battery without side effects such as HF.tact

and then the next important factor is the maintaining low price economics always important so let's look about functional polymer separator so usually in the battery the optimal operating the temperature typically range from 20 to 60 degrees Celsius but in this range the battery can function effectively without the significant content degradation it

Even when considering thermal being developed in the power pack used for electric vehicle or the EICS system, the maximum operating temperature generally expected to remain below the 100 Celsius. However, one of the common challenges in the VITIMAT battery is thermal run-on-A. Currently PE or the PP separator is quite common in the research and battery industry.

these materials have a relatively low melting point around the 140 to 160. moreover they tend to shrink noticeably at the elevat temperature like this one so which can read to internal short circuit and the range is serious safety conditions so to address these kinds of the challenge like as the three wide the

recognize the strategies have been proposed and are actively being is propped first thing is the PPP or replacing so replacing the materials with the high matting point like as ETFE, EI or polyamide so most of the case the thermal shrink calculation range from the 130 to 180 these kinds of the polymer materials

have a high melting point over 200 Celsius. So that is the good option. Second thing, increase molecular weight of the polymer. Generally when the large molecular weight polymer had no molecular chain length and the the low number of chain ends in the unit volume. So the movement of the polymer chains is the hinder dirt significantly.

So eventually leading to the high melting point. So attouring the molecular chain throat is also effective method to change the melting temperature of the polymer. Third, the modifying the separator with the inorganic.

inorganic nanoparticle or flame retardant to reduce thermal vulnerabilities is also an efficient method to enhance thermal stability. So we can think about the in that case with mixing with the silica and polyethylene, their the stability is quite good.

Thank you.

so in this section we can find the change the material from the polyethylene, polypropylene, polyethylene glycopheraflactate, the poly-MI is quite stable this kind of high mapping point and also glass fiber is very high 650s so just change the material we can get very some thermal resistance.

separator.

As the internal temperature of the battery increases, the functional separators are capable of shutting down the battery at high temperature. This is attributed to the melting point of some component in the polymer separator that blocks the force structure and thereby prevents the transportation of the liquid ion. So we call it reversibly thermal induced shutdown the separator.

So these kinds of things are highly desirable to its full, other than separate materials. So with the saved and reversible shutdown functions for the battery lithium-ion battery, presently several technologies have been developed for reusable thermal response lithium-ion battery. One of the examples like PVP-TI-02, a composite operator was designed to have a reversible shutdown at 60 degrees.

60 Celsius and then the another thing is the shape memory polymer or the promising candidate for the fabrication of the battery separator. So the shape memory polymer we call the SMP. SMPs show thermal in visual shape deformation due to their phase transitions. So one of the the best example is polyretton.

depending on the structure of polyurethane so we can make different kinds of thermal and use the shutdown the separator so the next thing is a separates a functional separator for the metal dendrite growth inhibitions so you know the rhythm this one is the shiny one is the rhythm metal which metal anode is highly recognized and promising the

anodic material due to its low electrical potential and the ultra-high thermological capacity. So, nevertheless, the disordered lithium dendrites looks like here. Dendritic position during the battery cycling motivated dramatically from change fluctuations of the surface of the lithium anode. Does the result in the break, the repair of the solid electrolyte interface? The solid electrolyte interface usually we have a rich metal.

some the solvent or the lithium ion or the cation they attack here they fall very thin the protective layer we called SEI the layer so if we have a some homogeneous and stable good SEI at that time is really good for the with you metal anode for the battery cycling

So we can consider if we make the good SEI layer. So we already know that that is the good battery cycling, the suppressed the rytumes, the dendrite formations. So some of the researchers have the investigate so several of the options for the rytume deposition. But on the one of the important thing, the first rytume deposition like here, uniformly if we make the uniform rytume deposition on the rytume metal onto the surface, that is the good thing with the good SEI layers.

So the written matter batteries, dendrite formation and gauze are considered the reading origin of the performance, decay and the safety threat. Currently, the various stages including engineering battery separator are massively developed to inhibit the dendrite formation and the growth inhibitions during the battery cycling. Initially, enhance the mechanical property of the polymer separator.

is expected physically suppressed the rhythm and right growth. Typically, aluminum oxide and the CNTs are often the selected to quote on the commercial separator that are using the lithium metal batteries. So like this one, after CNT introduction into the battery separator, the original separator has the better the mechanical properties with

flexibilities and physical restrict the lithium then drive the growth. Carbon-based materials, coating materials, are of the great interest owing to their satisfying the electrochemical destabilities and the mechanical properties. And then the extra, the another materials including the aluminum oxide or the boron nitride or

the silica. A lot of the options is they have the potential candidates for improving the metal dendrite force inhibitions and more of another functionality of the thermal safety. The next thing is about the fully sulfide shuttles. The research on the lithium-suffer battery system has long inches against the price due to the complexity of the CC system.

So these kinds of the sulfur when the battery is discharged, the solid state S8 sulfur is changed to the liquid state, lithium poly sulfide. And then finally, they changed again the solid state, lithium sulfide. But then in that case, these kinds of the poly sulfide liquid state can diffuse the lithium side and then the...

if they move to the lithium metals the lithium polysulfide can react with the lithium metal and they form the irregular the polysulfide and the lithium disulfide the SEI layer. So already we know that if we have a good SEI layer at that time is good for the cycling stability of the rich metal anode

when they react with the polysulfide they can they make the irregular the polysulfide lithium disulfide SCI layer so that is not it's some stable of the the batteries the cycling the stability so the reducing the polysulfide of the shuttle effect that is the key that creates for the medium-sucker batteries

So recent progress in the advanced separator are aimed at the high 70 mAh battery. The one is the protracting and the diffusion of poly sulfide to surface the shuttle effect. Just suppress. So poly sulfide. And the second thing is to reactivate the deposit dead sulfur containing certain species.

be activated. Third inhibiting the dendrite growth in the lithium metal dendrite growth inhibitions. The various functional layers including the polymer, carbon, the metal oxide and their deposit have been applied to controlably modify the separated for better as a battery performance.

with the distinct difference in positive and negative charge of the for the lithium cation and poly sulfide anion the use of the ion the selective separator is a straight idea so it is expected that ion selective separator can block the poly sulfide and just the lithium cation is the path through so finally they maintain the good which by transport and also protect the poly sulfide from the cathode side

let's talk about some things first approach involved with the coating separator with the functional materials that can block the polyseptide so that is things as shown in this kind of video the one still demonstrates that coating the separator with the dopamine of substance derived from the muscles can selectively lock the polyseptide effectively enhancing the battery performance

The second approach is to synthesize new polymer material to fabricate the separator itself by introducing special functional groups into this polymer separator. It is possible to select the threads with lithium ions while blocking polysulfite. So this kind of method can improve the thermal property of the separator.

That is a good example, PEK, poly is a ketose, an engineering plastic, having newly synthesized and applied to the lithium-sucker battery. The third thing is involving modifying the structure of the separator. Through the precise structure design, ion conductivity can be enhanced, while physically preventing the diffusion of poly sulfide. So these kinds of three things is the good

the options and example for the suppressing polysephize shuttle in the lithium-sephalic batteries. So already know that during the operation of the lithium metal battery, commonly known as a S-Litium metal, SEI, solid electrolyte interface is formed between the lithium metal phase and electrolyte phase by spontaneously chemical reaction and the electrochemical reduction of electrolyte.

SEI is responsible for not only embodying the continuous parasitic reaction between the electrolyte and electrode but also influencing the physician and stripping behavior of the lead ures. Let's think about SEI formations. So usually SEI formation on lead metal is considered two major steps one is chemical lead

reaction seconding electrochemical reactions so the chemical reaction means the metallic lithium metal is chemically reactive toward almost all known to chemicals and the immediate contact when the liquid electrolyte injects into the rich matter battery doing the batteries assembly chemical reactions

between the liquid metal and the liquid electrolyte take place spontaneously and instantaneously. So consequently insolubable products are formed on the liquid metal surface. So another thing the electrochemical reactions by the decomposition of some material they can form the SEI layers. So,

To prepare stable SEI layer onto the metal anode, the functional material coated separator can accelerate it. For example, a fluorinate self-assembly monorail we call FSA-Line that is the material SILAN based atmosphere as a sacrificial layer on the Bohemite

new OOH, which is only separated at a separate. These kinds of coatings form the stable and robust SEI layer. So the presence of these kinds of separate feature layer significantly is in the formation of a stable SEI especially, with IF without the extra site reactions.

So moreover they have a negative charged some the point onto the separator. The negative charged some the point in the separator, it facilitates the rapid accumulation of the lithium ion in the surface. So thus the discharge of LiF the rich SCI component regarded as a stable SCI layer is rapidly generated and deposed onto the lithium metal surface after set productions in the first cycles.

Then next thing for the flexible batteries. So you know these days wearable electronic devices. It's very important even the sensor or the smartwatch. So these kinds of wearable devices have accelerates the development of the elastic, self-healing electrode and gel-based electrolyte with the flexible structure and the properties

much this advance in the electrode and electrolyte, better-safe separator also needs to mechanically adapt heat, particularly capable of the reversible shaped formations. So from the PE or PP, they have quite good proximity, but their tensile strains less than 50% and begin to drastically deform at the relatively low strains, making them unsuitable for highly stretchable device. To overcome these limitations, researchers have integrated elastoma into traditional separate structures. One example is the

is that the combination of polyurethane with the polyvinyl fluoride which can adhere well to electric even at the high temperatures around the 60 size juice is provide excellent iron contact and enable the stable operation in the stretchable battery configuration. Additionally the polymer gap R being applied as the flexible separator

taking advantage of their original distractibility. Another the promise in the innovation is the integration of dendrite detection system directly into the separator. These kinds of things actively shut out the battery if the dendrite grow and reach the separator later, thus preventing the dangerous short circuit or the thermal runaway. So, another example is about

some assembly strategy of using the cellulose fluid system to modify the film was used to develop the composite film as the separator. So these kinds of combining the system due to the hydrogen bonding of the cellulose macromolecules and the steric hindrance of glass microfiber

a gradient and the hierarchy pore structure was constructed in these the films. So these kinds of things, these little bit loosely, coupled the architecture. Its micropores were transported in the stubborn structure with the lamella, medial, the pore separator. These kinds of things are good for the lithium ion, the transport controls, and the mechanical properties. And also even there had some quite big structure, but it's good high flexibilities.

This is just one of the examples but we can find a lot of the options. And the next one is the separator as a rhythm source for the recycling degraded cathode. So recently a functionalized pre-mediation separator is proposed by researchers to directly regenerate the de-wide date and

LFP cathode. Compared with the existing recycling strategies for restoring LFP cathode, this is the rather green recycling method without destroying the original structure, greatly reducing the cost of the remanufacturing of the cathode electrode. One of the examples, using the lithiums and carbon dioxide, lithium CO, these kinds of materials

can serve as a sacrificial agent to provide extra lithium source by these kinds of reactions. And also they provide the lithium ions to the electrode systems. So it helps to decrease the capacity of fading. That means they can read to improve the lifespan of the batteries. Also, the watchability of the separator already knows that it is very important.

the wettability, very important for the ionic diffusion. So we already talked about that the inorganic nanoparticle, carbon and the fiber composite or quartz separator can enhance their performance. These materials are modified on the polymer substrate to form a composite separator with improved our matabilities.

for example a hierarchical porous structure with the nanosilica or the nano another the materials so was designed to increase the electrolyte of tank so another option like titanium oxide or the alumina is another the candidate for the improved the wettabilities

and also recently from the 100% inorganic material some new material, metal, organic, framework or some new material, MaxSins so these kinds of things are expected to utilize for functional separators

Next is the fabrication method of polymer separation. Currently, the most popular commercial manufacturing method is the dry process or the wet process. These kinds of methods could also be used to produce a birayer or multilayer separator. Then the primary filings are obtained through the solidifications and the nanopores polymer filings are obtained.

obtained by stretching the films. Usually the price of these commercial separators varies from the $1 to the $10 per square meters, but the pores may reform at the elevated temperatures. In addition, the several other technology for the next generation battery could still be used to produce the functional separator.

So these kinds of the process usually we can think about. Polymer melting in case of dry and polymer solution in case of wet. And then these kinds of wicked state of polymer is changed to solidification and then there stretchings and they can make some kinds of the crystal phase or the stretchings and then cuttings that they checked in. In case of the stretching, there are two-step biaxial or the uniaxial in the case or a separator.

this asynchronous stretching and asynchronous stretching there are two methods. Depending on the method, they have a little bit different kinds of the mechanical property or the thermal properties so we can know which is the good for the battery science. So I prepared one of the examples, the conventional process for the fabricating the polymer separator. Thank you.

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So I explained previously that the fabricating polymer separator looks very easy, but as you know, the process consists of a lot of the process, extrusion, melting, stretching, and welding. So it's not easy, but it looks like it's easy. So the next thing is the modern manufacturing techniques. So to prepare the functionalized polymer separator, the modern techniques are developed, including the solution castings.

deep coating, electrospinning and phase inversions. The solution casting looks like here. The oldies technology to make the polymer film can be modified to produce functional separator by modifying precursor in advance. And also just mix some extra materials we can make easily. The deep coatings is one of the most

convenient method to prepare cozier separator by just immersing the separator produced by R technology into polymer or inorganic particle solution the purpose of this method is to enhance the thermal resistance relitium and battery by the coatings the primary separated with another layer however the quality of the coating separator little bit decreased after manufacturing since the thickness of the coating in the layer is harder to control

So this method requires the excellent flexibility of the substrate. Otherwise the solutions are difficult to spread on the matrix. Electrospinning is another technique to prepare micron and nano-side fiber. I already introduced a lot of things like non-oven, with some separator. So the benefit of this method is that it created a separator with a high porosity, large pore size, but weakened the mechanical

strength. So these kinds of things combine the composite method that can show the excellent safety and the battery performance against the previous just only one single the electric spinning. Another thing is the phase inversion. Just change the solvent and the solubility of the polymer using that we can make different kinds of the power structure.

So that's the, already I explained it, the electrospinning, this is very simple techniques to prepare micro and nano size fiber. And also it's quite known as, it's good technique for the membranes, even the rich man batteries and some biological applications, a lot of things. So I think this is good for the understandings for your, the future, the research topics.

including the lithium-ion batteries, the biological application, the water treatment, even the air purifier. So everyone uses these kinds of things to make the separator or just the polymer films. Electro-spinning is an established technique for the manufacturer of fibrous components for medical devices. During electrospinning, a syringe pump feeds a viscous solution through a needle.

is connected to a high voltage, ejecting a thin jet of the solution. The jet accelerates towards a target collector held at an opposite potential and thins considerably during flight. Dried fibers are then deposited as a non-woven mat, with each fiber being about 10 to 100 times thinner than the width of a human hair. Electrospun fibers can be used as simple mats and cut to shape with fibers of random, aligned or layered orientation. The technique also allows for the coating of complex geometries and the manufacturing of specific structures like tubes.

Different polymers can be used for this process and devices can have an opaque or transparent appearance. The ElectroSpinning Company is a global leading manufacturer of electrospun biomaterials for medical devices. It can be used in a variety of clinical applications.

So the next thing is a phase inversion. Previously, I just explained phase inversion just due to the volume solubility and the solvent. So they can form the forward structure. But this kind of thing is really good for understanding the phase inversion techniques. So the phase inversion is capable of creating forward structure by the preceding.

process where the control ball, the polymer transformations from the wicked state to solid phase occurs. So for example the phase inversion casting techniques was up to fabricate an inorganic-organic hybrid polymer and also PVDF land also is quite common. Unlike electrospene, it requires a homogeneous polymer solution when fabricating polymer-polymer composite.

separator because distinct polymers need to be dissolved into the same solvent which can limit its application for few polymers combinations. In general, its cost advantage and applicability to most polymers make it popular method to produce separator. Phase inversion is the most common technique for producing polymeric membranes of a variety of morphologies. The technique relies on the phase separation of a homogeneous polymer solution in a non-solvent medium where the polymer does not dissolve in but the solvent in the polymer solution is fully miscible. The membranes can be flat or hollow fiber.

Furthermore, using various templating methods or by making use of fluid flow instabilities, non-conventional membrane geometries can be formed, such as corrugated sheets, twisting, or meandering hollow fibers. Using this technique, dense membranes, porous membranes which are symmetric throughout the cross-section, or asymmetric with a selective skin layer can be formed. In a typical case, the polymer solution is first filtered through a metal mesh to remove dust or other suspended solids that may cause defects in the resulting membrane. The polymer solution is cast at a certain thickness to have a flat membrane, or spun through a spinneret together with a bore liquid that forms the hollow core of the fiber. Before coagulation in a liquid non-solvent medium,

A precoagulation step may be applied, such as solvent evaporation under the flow of a dry, inert gas, or vapor-induced phase immersion in a humid air atmosphere. These processes, in the case of hollow fiber membrane fabrication, take place in the air gap between the spinneret and the coagulation bath. Rate of phase inversion, which is a crucial aspect determining the resulting membrane morphology, can be monitored online under a microscope by placing a drop-off polymer solution between a slide and a cover slip and introducing the non-solvent from the side.

The polymer solution becomes opaque upon phase separation, and by making use of this feature, the advance of the phase immersion front can be monitored.

So in the future, the polymer separator may become some, I think, disappears, because since the solid state electrolyte in the solid state battery can also serve as a separator. However, all solid state batteries still face several issues that need to be resolved before the separator can be complete and animate. In addition, the cost of the solid electrolyte is high,

the some ranging from the 100k dollars per kilograms or the 200k dollars per kilograms so the price of device such as smartphone equipped with the also listed battery will also be high so one of the example so we have a Apple watch with the wicked the left light upwards usually.

so maybe we can buy some apple watch like three thousand dollars so the i think uh accordingly the liquid liquid-based battery with the separator.

So may continue to be using the low cost product while high end like as luxury luxury product may adopt battery with the solicited electrolyte but even the price is the five times expensive just like as just the one-time charge for one week one week is quite the

acceptable systems. So that is the summary of the polymer separator parts. Polymer separators play important roles for the battery performance and the safe operations. For high energy and power density, the polymer separator should be thin, the high porous the possible.

but sometimes we need to get some good mechanical strength with the thin and good mechanical properties. For another thing, there are many good options. Ionic diffusion is very important. So we have to increase and improve the ionic diffusion, the characteristic of the polymer separator control, durability, porosity, and thickness. So moreover, we can design the functional separator

So with the coatings or some designing with the new structure there is another option of the separate research for the advanced battery technology Thank you very much