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This chapter is about the polymer binder in the battery. So let's talk about the polymer binder. Polymeric binder, the small components could apply the very important law of the bridge, glue or the adhesive. So between the electric components and the energy storage device. So what is the electric component we can think about? Firstly,

we can think about the metal foil. So we called substrate. And another thing is etymometrials. Usually they have some reduced properties and the conductive carbons or conductive agents like as the carbon black or the CNT or the graphene.

we can consider a lot of things and then the polymer binder looks like noodles. So anyway the binders can have a significant impact on the battery performance. In particular the repeated charge discharge cycle of the battery can result in the changes in the electrode volume looks like this one. So in the mining battery life and child life this

This can be resolved with a specialized binder which can have various functionalities such as high mechanical properties, high strength, high electrical conductivity or ionic conductivity, and electrochemicals and good performance. So already we talked about that the polymer binder created bridges between the current collector, conductive carbon and active materials to maintain the

electrode integrities so during the adhesion polymers initially are these with a wrap around the different components of the surface like this one then the penetrate the electron particle pore looks like here and there is a solvent action so let's find through the drying or the polymerization absorption on the particle surface from the boundary layer looks like here and

curing layer or the free layer while the curing and the free layer performance primarily depend on the adhesive intrinsic properties. Currently the six the different theory about the adhesive mechanism of polymer have been established firstly mechanical interlocking theory and electrostatic theory, wetting theory and the chemical binding theory and

diffusion theory and the weak boundary barrier theory in general the different theories complement each other with the mechanical interlocking and the chemical bonding theory widely used to explain the bonding mechanism between the polymer and the some the electrode matrix so as a representative polymer binder pvdf poly

Dini lo.

Polyblenid fluoride is widely used in the battery, as or as fluorinated plastic found everywhere, like as the coatings and the films. In the battery, it is served as key bind materials, maintaining the cohesion of the electrode particles and adhesion to the current collector. PU-DEF is typically produced through the amalgam or the source pansion polymerization using the

Peneliden fluoride monomer looks like here.

Looks like here. And also we add the surfactant and the initiator for the polymerization. It has a semi-crystalline structure with about 50% homophores. The monomers join to the head to tail the configurations, ensuring regularity and performance. The main mechanism of audition in conventional PVD app

the van der Waals force. Already we talked about these kinds of force in the polymer chapter. The van der Waals force relies on intermolecular interactions in U-nodes. In some modified PVD system, two mechanisms are observed. The van der Waals bondings affected due to the high molecular. Sometimes these chemical bondings establishes between the polymer and the metal substrate for the surface.

PUDF is also used with the chemical, electrochemical and thermal stability primarily due to the strong CF bond replacing the weaker CH bond so we can compare the poly-acetylans. So moreover it offers the electrochemical the windows over the 5 volt and the decomposition temperature up to 400

Celsius. So because of these properties, PVDF has been the standard binder in the lithium-ion battery electrode since 1917. So one of the some funny things, so almost the 50 years, but I'm still we need or we are using the same the binder, but then the cast material is a little different, carbon material is a little bit different, but still we need the

PVLIPFizer. However, this part is a long-standing news. It presents environmental challenges, notably the need for toxic organic soilments like N-material pyrolythons during the processing. With increasing environmental regulation and a push toward greener manufacturing, QVDF is now seen A the the regency materials that must be eventually replaced in all the improved

the base on the water the base the binder such as a carboxyl meticellulose or the side of the rubber or the polyacryl oxide is totally the accuracy based systems so the polymer binder generally formed the two primary contact types so each of each of which apply a critical role in the determining adhesion strength at mature density and lateral stability

Accordingly, the optimal contact structure should be selected based on the specific electric design and the application requirement. So, while contact is a matter, the physical interaction between the binder and the active material So, they affect the electrical conductivity, the ionic pathway, and the mechanical stability, and the cyclical light.

there are two representative contact type one is the line contact type and second thing is point contact types so I think that most of people thought about the polymer binder looks like the noodle like this one but in the line contact it totally looks like the noodle because the polymer binder cover the polymer

polymer binder cover the active material but I mean the point contact type looks like the point but we can expand the this kinds of thing the polymer is looks like the ramen noodle is entangled the things

the point contact refers to the structure while the bind connects the active material particle and localize the small point. This type of contacts are easy the ion transport due to open the pathway because the lithium ion is outside and they the cut path through the liquid electrolyte some system so it's easy to

meet here but in case of the line contacts sometimes the polymer binder is evenly coated onto the active material so the lithium ion contact is not easy. But in case of the point contacts offer the weaker mechanical strength and the raw electrical conductivity. So it is the commonly seen with the PVD binder.

can lead to structure in safety over the rifted cycles because there is the line contact type. So line contact describes a broader more continuous boundary between the binder and the active material surface. This enhances both mechanical integrity and electrical connectivity of the electrode. While it is my slightly thinner eye mobility I already talked about is not easy to the path through the microstructure and

due to sometimes due to the thick coverings it's generally prepared for high density long light battery established when using the water bay cmc or the SDRs looks like cmc the structure looks like here there are many the hydroxyl or COO minus COO minus and the ether it's easy to the form the the intermolecular the

the force looks like the hydrogen bonding a lot of things and the styrene-dyrene lava looks like here they have a styrene functional groups and the one double bond in our organic chemistry some come back to the molecular interactions we studied the representative type of molecular interactions the covalent bond and the hydrogen bond dipole-dipole interactions

and the van der Waals force and the ionic bond. Each of these interactions has a different strength and words, covalent bond, to form the backbone of the molecule like as C, C, F,

while the hydrogen bond and dipole interactions often stabilize the stabilize molecular structure

Van der Waals force, although it is a little bit weak and universal and hold even the non-polar molecules together. Ionibones provide strong electrostatic attractions between the especially charged groups like plus or minus. These molecular interactions are not only the fundamental industrial molecules but are also widely utilized in the polymer. They govern the important aspects such as chain packing,

green-style unity, flexibilities, and mechanical properties. And they explain why different polymers show such as a wide variety of the V-high layers and applications. So let's take a closer look at the different type of bonding and interaction in the polymers. So I think we've repeated the previous things. These interactions range from the strong covalent bond

much weaker intermolecules, I suppose, and together they determine the overall structure and the property of the polymer. Primarily covalent bonds, there are strong bonds in the polymer, looks here. They form the polymer backbone holding the atom together in the wrong chain with that covalent bond. Polymer would not exist as a stable macromolecules, one of the For example, the person who is

other prokinization here. Hydrogen bond. Hydrogen bondings occur when hydrogen atoms attach to electronegative atoms like oxygen, nitrogen, like here, is attached to another electronegative atoms. In polymer, hydrogen bonds play a key role in the stabilizing structure. For example, they give the cellulose its rigidity and also crystalline the proteins and the nylon.

Next is dipore interactions. Dipore interactions arise when the molecule with the prominent dipore attract each other. In polymer these interactions are weaker than the hydrazine bond but still contribute to the chain-chain interactions like here. Especially in polymer with the polar groups such as PVC, Wanderbeer's force. There are the weakest

and the most universal intermolecular forces are running from the temporary fluctuation in the electrons and density even the non-foli the polymer like it's polyethylene polypropylene so are held together in the solid state by the van der Waals force they might be weak individually but collectively they are significant I only bonds and interruptions like it's zinc to flux like it's O-

In some polymer, ionic groups present along the backbone or the side chains the electrostatic attractions between the positive and the negative ions from the ionic bonds which are much stronger than the hydrogen bonds or the dipole interaction. These ionic interactions give rise to materials like ionoma.

which are used in the specialty membrane and the packaging. In summary, polymers are had to gather by a wreck of the interaction from the strong covalent bond to the hydrogen bond and the dipole-dipole interactions and weaker boundaries, the force. In some cases, ionic bonds also, the balance of these bonds, this means the wire,

the polymer is rigid, possible, crystalline or sometimes amorphous and ultimately defined is the application to binder, separator or the electrolyte, a lot of things. So we classified the type of the binder. The polynomial binder is

the battery can be brutally divided into two cutlery one is the natural second thing the synthetic binders are the man-made polymers typically derived from the petroleum source they are engineered to deliver the excellent thermal and some chemical destabilities like here which is why they have been widely used in the commercial battery systems however soon that the binders

are usually sold in organic solvent such as M-methyl, pyrolidones, and MP, which possess the environmental highest conscience. These solvent must be carefully recovered and recycled during processing, which adds significant cost and complexity to battery manufacturers. On the other hand, the natural binders are derived from the renewable biological source like ooze, sometimes the seaweed,

sometimes from the some like it's a route they are typically the water soluble making them much more environmentally friendly and the cost-effective during the process productions. Light of the growing the environmental issues and the strict regulations, they are interested in recognizing the synthetic binder to the natural binders.

The representative binders include the PVF, SVR, the PAA, the polyethylene oxide. Common natural binders include the sodium alginate, carboxymeticellulose, chitosan, all the gums, etc. Also the various gum and natural rubber extracted from the trees, although the symbiotic binders still dominate due to their

durability and electrochemical stability and the easy to process things. The transitioning to the natural binder is becoming essential for building for sustainable, environmentally responsible the energy storage systems. Among the standard binder SBR and PAA, they can use the in-accuses system. So one of the examples is good for that some we combine the the advantage of the synthesis binder and the natural binder.

So first let's look at the CIMED binder. The CIMED binder is the man-made polymer artificial. That means it's used to hold together an electromagnetic lithium ion battery electrode. Without binder electrical particles would not get connected. So like this current collector. So usually metal foil and without binder looks like here. This is a carbon.

active material would not stay connected and the battery would lose the portals. The advantage of the Syntheswinder includes high mechanical strength which have maintained the structural integrity.

the chemical thermal stability allowing the binder into the harsh electrical environments like is the battery cycling over the 5 volt looks like here the compatibility with the various electromagnetic materials making them the is the various the application for different battery chemistry sometimes depending on the the polymer binder is not easy to the this person

because of the interaction of the intermolecular is a active material and the polymer binder sometimes they have don't have a good the dispersion property the polymer binder it looks like so it's not easy to the dispersion but usually this is the binder they have a good dispersion the properties and already they already showed the proven the performance in the commercial scale batteries so which is why they are you ideally using the industry

However, there are also challenges on current trends. One major concern is to use toxic solvent such as NNT during the biomechanics processing. These solvent raise serious environmental safety issues. Another limitation is the high cost of the systems in the deployment, which can affect the overall battery manufacturing cost. As a result, there are strong research trends toward developing the water-based low cost.

the sustainable the synthetic binder or the replacing with some natural binders. So let's look at the example of the synthetic binder which the lack of excellent stability like as the electrochemical thermal stability and mechanical property. PVDF is mostly common using the positive electrode and heat in the minimum batteries. It is

It maintains stability over the wide the voltage.

during some battery operation and does not react with electrolyte ensuring long-term battery the cycling operation. However, PVDF is sensitive to the environmental conditions such as a humid affecting its performance and bonding effectiveness. Moreover, PVDF is relatively closely compared to other Hesibu type.

so in case of the PVDF primarily mechanical bandwagon force already we talked about that but on some modified PVDF that is controlling the crystal structure so we can make the different kinds of the mechanical bondings so in the PVDF there are many types of the crystallinity alpha, beta, gamma looks like here so poly tetra-fluoroethylene TTFE we already known as well the teflon

Teflon is a polymorphine with a very very unique property. It actually is in extremely high resistance to almost all chemicals including the strong acid phase and organic soil bags making it very popular in the chemical industry and the laboratory equipment. PTFE has excellent mechanical properties can maintain and

this very stability at the extreme the temperature when I continuous use temperature range typically between the minus 200 Celsius so and 260 Celsius and they can withstand have even higher temperature for short period however PTFE has very low surface energy making it a nonstick on the most surface

So why these the properties advantages in the some applications but then the raw surface energy can lead to insufficient adhesions when P2P is used as a adhesive. Bottom these days as a binder PTFE is very popular in the solid state battery. So with the dry,

thing. Polyacrylate acid we call the PAA and so now there are some things PAA lithiums the lithium polyacrylate looks like here

These water-based VEC are valued for their environmental friendliness and the low cost. They provide good bonding strength through the formation of a hydrogen bond and physical entanglement and suitable for the application requiring increasing production, efficiency and the reduced cost. However, their stability in the high-humid steel is very full. So depending on the EPA that continue the contents in the system, sometimes it's different ionic quantity.

So next the synthesis finder is styren butain buta SVR is produced through the synthesis 1,3 buta 9

the styrene monomers and it is characteristic depending on its molecular structure including the ratio of the styrene to the butadians, the cross-ranking type of emulsifier and the polymerization temperatures compared to the PVDF SBL is a better elastomer because it has a little bit flexible as a better binding properties and can withstand higher temperatures

it can effectively buffer the volume changes of the electro material during the battery's charging charge cycles so reducing the shading of the active material thereby improving battery cycling stabilities so the binding mechanism of the acid ears Also, they formed some chemical bones.

SBR the emergine itself is a balance of the hydrophilic and hydrophobic properties. On the one hand is organically combined graphite through the hydrophobic CT and on the other hand the hydrophilic groups react with the group on the copper foils like a current collector through the condensation reactions. So with the CMC

carboxy, usually the SCBR, so combined with the CMC, sodium CMC, the binder, the mixed landing system, the CMC, the binder acts as a stabilizer and suspension dispersion, assisting in theization of the SCBR and ensuring more uniform dispersion of SCBR while the repulsive action of the special charge ensure the stability of the entire system.

So let's talk about the natural binder. Natural binder is a polymer binder derived from natural material like plants, algae, all the other biological sources used to bind active material in the lithium-ion battery electrode and they're attracting attention as a green adhesive and to the synthetic binder. The advantage of natural binder definitely they enable the water-based processing

So that means no need a toxic servant and their environmentally friendly and biodegradable is much more sustainable. There usually were cost compared to the certain synthetic binder and properly the optimized They can provide good mechanical properties, electrical headcan performance, and it is perfectly optimized. Very simple data.

However, natural binders also face limitations such as their sometimes less chemical state compared to the synthetic binders. They can degrade the other high temperatures or the certain electrolyte systems. So the research is still ongoing to improve their performance so they can meet the demands the high-performance the batteries

So one of the representative examples of the natural binders is carboxymethyothelolose. I already introduced them with SDR plus CEM systems. The sodium carboxymethyothelolose, the most widely used and the largest volume cell type in the world, is cell reserve active with the degree of the polymerization of glucose of the cell.

102,000 and the relative molecular mass 242.16. It is the wide, fibrous, or the granular powder, odorless, tetelies, and hydroscopic, insoluble in the organic solvent. With the SBR, cyanobotermolver, in the rich man battery, graphite, and also complementing this principle, which is the result of the wrong-term industrial practice.

If only the CMC is used as elusive condition, the electrical seat thickness is dense, the rolling process, or the no compacting density of the electrical seat. In the electrical seat, due to the requirement of the high energy density, the graphite electrical sheet must be rolled and the compacting density is high.

So they require the extra polymer material like SVR. We already talked about it. SVR cannot be used alone as an adhesive because it's difficult to prepare slurry like this version. SVR does not have suspensions, disperfections, slurry, and cycles. and too much SVR will cause a lactose seed.

swelling in the lateral system. So the combining together they show the synergistic the effects of the SVR the CMC the advantages. And then next is arginate or we can call the sodium arginate which is excellent biocompatibility and the gel forming ability. The arginate is commonly used as a natural polymer binder and

Also in the food industry and medicine and cosmetics, it can quickly form stable gel in water, suitable as it sterilizes all the thick nuts. Arginate biodegradability and the renewable sources make it an environmentally friendly materials. However, arginate main drawback is the sensitivity Bye.

which may affect its stability in some applications. And also the alginate binding effect mainly depending on the carboxyl groups on the molecular chain which can form a stable three-dimensional network structure through the ionic cruise linkings and also they have a hydrogen binding also. So

like this kind of thing sometimes the alginate can enhance the mechanical property of the yeast jar by course linking with the metal cation such as a calcium, magnesium, sometimes like this one and also the sodium sometimes however the alginate some steels they have some a lot of the uh this or the vintage like this the

thermal stability and sometimes in the swelling and the elastic cities that is the problem so if we improve there some mechanical and the chemical that's the catalyst it would be the good options for the green the polymer binder kai-2-san is a polysaccharide driver by departure the oscillation from the kittens.

so it is one of the most abundant natural biopolymer so we can imagine the kaitosan is from the crab shell or the sometimes sometimes from a lot of some hot the shells of the some the sea some materials

and also they have after the acceleration the chitosans have the acetylation of the groups and they have some the armine functional groups and also the percentage of monomeric the acetylation unit is defined the degree of the acetylation which is essential parlemental for ketene and the

kitesan detecting the chemical physical property of the polymer. Acetylglobine and kitesan bind as well as the hydropsyl and the amino, the polar groups form the dipole-dipole interactions with the surface of the silicon like as for example silicon materials and the copper current collector resulting in the mitigating volume change during the battery the cycling and the some

charging and discharging and thus enhancing the cycling stability of the battery in that route. So in particular the natural polymer binder containing its armin groups are very very rare and their distinctive features is the ability to exhibit various properties by utilizing these armin groups like as cross linking with the COOH or the epoxy a lot of some the chance to use the armin functional groups.

For the ideal electrode, every active particle should be rationally shaped, sized, dispersed, and wired to the current collector and to the solid or the liquid electrolyte with the raw resistance and the continuous internal pathway. Thus, the development of the novel binders system that can postulate both electrons and the

lithium ion transport provide the improved mechanical mechanical properties and adhesivity, flexibility, enhanced surface capabilities, improved disparate stability of the active particle is of the particle importance for next generation high energy density and high powered lithium ion batteries. So first strategy of the binder design for the next generation, the battery application.

Polymer binder with the high adhesion strength can be a good starting point to prevent the dissolution the ramination of the active material from the electrode like this one. Considering the interface failure mechanism the adhesion the strength is determined by the chemical the bondings and the intermolecular the interactions like here the mechanical interlockings.

the adhesive force between the binder and substrate and rather depending on their mechanical molecular structure and the surface characteristic. The general strategy is to modify molecular structure of the binder by incorporating the polar groups and its polymer backbones or even in the side chain is okay such as a hydroxyl, carboxyl or the

amines groups. So the CMC originates like polyacryaxide, gums, Hytosan and other binders possess an abundance of these functional groups and they can form strong interface interaction hydrosion bond or copalic bond sometimes or sometimes they have some ionic bond. So these binding poses are much stronger than the van der Weyer's pose and

the hands improve the adhesion to maintain the integrity the stability of the electrode so using these kinds of things making the hydrogen bonding ion-diple interactions require stronger stress for the dissociation and they can recover more efficiently so generally the hydrogen bond and ion-diple interaction at the interface are formed between the boiler binder and oxide

surface of the metal-chlorid-collecting material especially in the anode systems. So in case of inase or delhesion astrayides it usually is the popular for anode side like a silicon or lithium something, graphite. Compared to the intermolecular interaction the chemical bondings are

much stronger and thus affecting the adhesion strength of the binder. Therefore, chemical bonding plays a pivotal role in enhancing the adhesion of the bind properties. A polymer binder with specific functional groups such as carboxyl or alleles can form the covalent bond and the ionic bond. In addition to form the hydrogen bond with the hydroxyl carboxylate of

also capable of forming the ASTO bond.

the bond between the binder and the hydroxyl group of the oxide the surface in the liquid batteries so these kinds of thing also is quite popular in the silicon anode. Silicon anode they have some OH group on the surface using these kinds of the condensation reaction we can form very stable the interface so mechanical the bondings cannot be classified as a adhesion mechanism at the molecular level but the physical property of bulk material generally occurring between the two surface

is partially pronounced for the rough surface. The non-reactive mechanical bonding process is weaker than the cobalt bonding process. Low viscosity polymer or the polymer solution can penetrate the fuse into the crack and the pore looks like here. And then the hardened with the dried providing strong adhesion during the manufacturing process.

moreover the intermolecular forces, the mechanical interlocking, polymer architecture are also important role in the modulating the adhesion the policies. Unlike the linear the polymer the branched polymer possesses the significant branching looks here a large number of the side polymer chain and thus capable of forming multi-dimensional contexts.

looks like here.

consequently the branched structure of the polymer binder can distribute the resulting stress to the multi-side chain reducing breaking pulses

the anchoring pointer like this because they connected several points so they have a lot of breaking point but they covered this way so it's easy to reduce the stress from the cycling chain also leads to a high adhesion autism.

Self-healing capability is also promising strategy for maintaining the lateral stability when the initial rupture of the binder to release stress.

why volume expansion is subsequently repaired by reversible bounding after stress release. Specifically, self-healing in the context of the DISC study referred to the capability of recovering the roast of the binder and the electrode or the binder-binder interactions in the previous cycle due to rods volume change from here here looks like here

Bandel-Wiret force is too weak to recover well and the reversibility is mainly provided by the dynamic bones, looks like here, which can be divided into two cutlery, dynamic covalent bones

non-covalent bonds. Generally dynamic covalent bonds require additional triggers such as the write or heat, pH value, or the catalyst to form or the brake and the therefore are difficult to use in the complex environment of the batteries. So dynamic non-covalent bonds is quite popular. The working principle of the rechargeable lithium-ion battery is based on the electrochemical reactions. The performance of the electrochemical reaction is mainly related to ion

ion and the electron the transport. So for the electric conductive binder a lot of the number of the conductive polymer has been synthesized such as the poly, aniline, poly, kilos or the poly, a lot of the derivatives so which consists of a high, high-lid pi.

Conjugated backboards for electrons transferred. In the neutral stages, these are the pi conjugates. The polymer has a lot of low electronic conductivity like as the semiconductor or the insulator. But the electric conductivity of this polymer is drastically increased when their chemically electrochemical oxide

reduce to polaron or bipolar state. Finding on the ability to donate or accept electrons. They are divided into the p-type and n-type polymer. So doffin is another one of the examples to improve their electrochemical activities. and also except for the

electric conductive binder. The ionic conductive binder also is very important. One of the best example is polyethylene oxide.

conductive binder. The ionic conductive binder also is very important. One of the best example is polyethylene oxide, PEO. There is still being intensive exposed and used even in the polymer electrolyte. So we are to talk about in detail the hoping the mechanism. So usually we can see like this one. These kinds of the ion transport commonly occur in the amorphous phase. The mechanism involved with the complexation of lithium.

ion with the oxygen of the ethylene oxide groups hoping the lithium is moving and the motion of the complexing segment is flexible. The PEO chain, the lone pair of oxygen and the flexibility of PEO backbone together with a high dielectric constant promote salt dissociation and parcelation and complexion over decompressions.

and consequently the movement of the lithium ion from here to there in the PEO matrix. That is one of the mechanism of the ionic conduction in the polymer matrix.