Electrode slurry composition containing solution-processed n-type conductive polymer

Abstract

The present invention relates to an electrode for use in an energy storage device, the electrode comprising an electron collector, an active material, and a conductive binder, the conductive binder comprising a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm.

Description

[Technical Field]

[0001] The present invention relates to an electrode slurry composition for the manufacture of electrodes for use in energy storage devices, an electrode comprising a conductive binder, and a method for manufacturing an electrode for use in an energy storage device. [Background technology]

[0002] Currently, nearly 100% of lithium-ion battery cathodes use poly(vinylidene fluoride) (PVDF) binder. PVDF is a traditional commercial binder commonly used in lithium iron phosphate (LFP) cathodes in lithium-ion batteries (LIBs) due to its favorable electrochemical stability, suitable electrolyte adsorption, adhesive performance, and high strength compared to other fluororesins.

[0003] PVDF is a unique fluororesin that exhibits adhesive properties to metals. This is due to its molecular structure, in which fluorine, an electron-withdrawing group, and hydrogen, an electron-donating group, alternate.

[0004] PVDF is inherently chemically stable. PVDF generally exhibits high stability against acids, water, organic solvents, oils and fats, and other chemicals. This is due to the strength of the C—F bond, which does not easily release fluorine and is less likely to undergo chemical changes. As a binder used in carbonate-based organic electrolytes, its low reactivity and solubility in organic solvents are advantageous.

[0005] Current lithium-ion batteries require oxidation resistance at the cathode of more than 4.6 V and reduction resistance at the anode down to approximately 0 V (relative to the metal potential of Li). PVDF has the oxidation and reduction resistance to meet these criteria.

[0006] While typical fluororesins are insoluble in organic solvents, PVDF is soluble in certain polar organic solvents, such as N-methylpyrrolidone (NMP), making it possible to use it for coating. PVDF binders swell in the presence of typical carbonate electrolytes, allowing lithium ions to pass through. Therefore, their resistance to ion diffusion within the battery is lower than that of resin binders that cannot swell. Therefore, they exhibit a property that makes them less susceptible to deterioration in the battery's rate characteristics than other resins. When the amount of electrolyte expansion is very small, the binder becomes a significant resistance component within the battery. The optimum expansion rate for a binder is thought to be approximately 20-40%.

[0007] Despite all the advantages mentioned above, PVDF has several drawbacks. First, its nonpolar structure allows only weak intermolecular interactions between the active material and the aggregates. Therefore, repeated charge-discharge cycles disrupt the homogeneous composite structure of the original electrode through substantial volume changes, resulting in mechanical failure and capacity loss. Second, PVDF is electrically insulating, necessitating the addition of carbon additives to improve the electrode's electrical conductivity. In conventional lithium-ion batteries, carbon additives are essential for forming an electronically conductive network within the battery electrode. However, carbon additives tend to aggregate, increasing the internal resistance. Furthermore, PVDF / C blends have almost no capacity on their own, so adding carbon additives reduces the overall battery energy density. Finally, the environmental impact of using the volatile and toxic NMP solvent in the casting process of PVDF / C / active material electrodes also needs to be considered. Therefore, significant efforts have been devoted to developing improved alternative binders for high-energy-density batteries.

[0008] Among these materials, sodium carboxymethylcellulose (CMC), sodium carboxymethyl chitosan (CCTS), sodium alginate (SA), styrene butadiene rubber (SBR), or polytetrafluoroethylene (PTFE) may be mentioned. Due to the presence of hydroxyl and carbonyl groups, many of these binders exhibit strong polar interactions and even hydrogen bonding with the surface of the cathode intercalation material and the anode conversion material. This same chemical property also makes these binders easily dispersible in polar solvents, allowing for aqueous processing. Like other standard binders, these polymers are insulating, necessitating the addition of carbon powder.

[0009] Therefore, polymer binders are no longer considered as mere binding agents, but also as components that contribute to the conductivity of the anode / cathode and the stabilization of the solid electrolyte interface (SEI). A good binder provides a strong binding affinity between the active material particles and the current collector to maintain the integrity of the electrode even under conditions where ion diffusion and side reactions are limited. In the slurry preparation process, the surface of the LFP particles is coated with polymer chains by stirring. The resulting slurry is then coated onto aluminum foil, and the electrode is fabricated by drying. Therefore, the polymer structure coated on the surface of the LFP particles has a significant impact on the performance of the electrode. An efficient polymer structure is essential for the one-dimensional Li-ionization in LFP materials. + To the extent that it helps alleviate channel shortages, Li + This can promote the spread of

[0010] For this reason, LIB binders have been increasingly investigated in recent years due to the design concepts of new polymer structures. As a result, polymer binders are positioned as strategic components to alleviate battery cyclability issues. In this regard, an ideal electrode model must satisfy several requirements. The first requirement is to maintain sufficient adhesion to prevent electrode delamination and separation during the charge / discharge process. The second requirement is to be compatible with slurry preparation and electrode fabrication, while forming a continuous conductive network within the electrode. This allows for the formation of a Li + The formation of electronic and ionic circuits is also promoted to maintain the mobility of ions and ensure effective electrochemical reactions. Meanwhile, ensuring the electrochemical, chemical, and thermal stability of the battery under harsh internal and external environments is also important. Finally, cost-effectiveness for large-scale commercial applications is also highly desired. Three major binder development strategies have been adopted for LFP materials. The first strategy is the traditional polyvinylidene fluoride (PVDF) binder used in commercial applications. The second strategy is environmentally friendly water-based binders. The third strategy is functional binders, such as conductive polymers or ionomer polymers, which are used to compensate for the shortcomings of the LFP structure. The use of efficient binders in LFP cathode materials can improve electrical conductivity and promote ion diffusion, thereby improving performance and long-term cycle life.

[0011] CPs have a backbone with an extended π-electron network. Undoped CPs are semiconductors. However, doping significantly changes the electrical conductivity of CPs to intrinsic electronic conduction. The dopant oxidizes or reduces the backbone of the polymer chain, thereby generating charge carriers within the extended π-electron network. CPs have been widely used in many industrial applications, but their use as binders in lithium-ion batteries has been limited by their processing difficulties. These polymers have poor thermal stability and are difficult to melt-process, and few CPs are directly dispersible in solvents for solution processing.

[0012] Among polymers, highly conductive poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (PEDOT:PSS) was investigated as a binder for LFP cathodes. The resulting electrodes exhibited a rate capability of 126 mAh / g-1 at 5 C and cycling stability with less than 1% capacity fade at 1 C after 100 cycles. While these values ​​exceeded those of LFP cathodes fabricated with conventional compositions, the PEDOT:PSS binder has several drawbacks. First, PEDOT:PSS is thermally stable only up to 150 °C. Furthermore, PEDOT:PSS is an expensive material, which increases the final cost of energy storage devices. Another drawback of PEDOT:PSS is that it is aqueous, which is why the use of a water-free formulation may be beneficial for some applications. Furthermore, PEDOT:PSS is acidic, with a pH of 1–3. This can lead to corrosion or degradation of the electrodes over time, potentially affecting the battery's lifespan and performance. Considering that PEDOT:PSS is a p-type material, this can lead to reduced charging efficiency and significant energy loss. Another drawback of PEDOT:PSS is its poor electrical conductivity and mechanical stability.

[0013] Therefore, there is a need for improved conductive binder materials that do not require conductive additives, are easily processable in solution with environmentally friendly solvents, and improve the structural integrity of the electrode. Summary of the Invention

[0014] In light of the above, the present invention aims to solve the problems in the prior art. To achieve this objective, the present invention relates to an electrode slurry composition for producing electrodes for use in energy storage devices. The term "electrode" refers to an electrical conductor used to contact non-metallic parts of a circuit. The term "energy storage device" is understood to mean a device that accepts energy, stores energy, and releases energy as needed. In particular, the term "energy storage device" as used in the context of the present invention refers to a secondary battery, also known as a rechargeable battery. In contrast to disposable or primary batteries, such energy storage devices can be repeatedly charged, discharged against a load, and recharged through reversible electrochemical reactions. Energy storage devices of the present invention may be configured in any size and shape, from button cells to megawatt-scale systems. The energy storage devices of the present invention may use a number of different electrode material and electrolyte combinations, including lead-acid, zinc-air, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), lithium-ion (Li-ion), lithium iron phosphate (LiFePO4), and lithium-ion polymer (Li-ion polymer). In particular, the energy storage device according to the present invention may be a lithium-ion battery, which uses lithium ions as a solute in an electrolyte dissolved in an organic solvent.

[0015] According to the present invention, an electrode slurry composition comprises an active material and a conductive binder, wherein the conductive binder comprises a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm.

[0016] The solution-processed n-type conductive polymer may be free of side chains. In the present invention, the term "free of side chains" refers to the polymer having only one carbon atom extending from its conjugated backbone. This embodiment offers the advantage of improving the interface of the active material with the nanoparticles and / or electron collector surface, since the side chains provide some distance between the π-system of the polymer and the surface of the electron collector, thereby reducing charge transfer. Furthermore, the solution-processed n-type conductive polymer may comprise a repeating unit comprising a centrosymmetric benzene ring as the backbone, an active hydrogen, and at least one electron-withdrawing group at the benzylic position. In particular, the solution-processed n-type conductive polymer can be poly(benzodifurandione) (PBFDO), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof, as shown below. The structure of PDADF-P is similar to that of PDADF, but lacks the heterocyclic segment.

[0017] Such solution-processed n-type conducting polymers may have thermal stability up to 225° C., as described in more detail below.

[0018] As mentioned above, the monomer may have a centrosymmetric benzene ring as a backbone, an active hydrogen, and at least one electron-withdrawing group at the benzylic position, which may be a carbonyl, carboxyl, amide, or alkoxyacyl group. [ka]

[0019] Furthermore, the monomer may be in the form of a heterocyclic moiety having a centrosymmetric benzene ring fused with at least one, preferably at least two, rings, preferably a five-membered ring. The monomer further comprises an active hydrogen and at least one electron-withdrawing group at the benzylic position. In particular, the monomer may be 3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione (HBFDO), 5,7-dihydropyrrolo[2,3-f]indole-2,6(1H,3H)-dione, or 3,7-dihydrobenzo[1,2-b:4,5-b']dithiophene-2,6-dione. [ka]

[0020] In particular, the monomer can be 3,7-dihydrobenzo[1,2-b:4,5-b]difuran-2,6-dione (HBFDO). In such embodiments, the n-type conductive polymer can be poly(benzodifurandione) (PBFDO), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof, as shown below. In PDADF, m and n can be the same or different integers. [ka]

[0021] The solution-processed n-type conductive polymer used in the electrode slurry composition of the present invention may be prepared from an ink comprising the solution-processed n-type conductive polymer and a solvent system, which may include a polar aprotic solvent and / or a polar protic solvent.

[0022] In particular, the polar aprotic solvent may be selected from DMF, DMSO, or a combination thereof. The polar protic solvent may be selected from water, ethanol, propanol, butanol, and a combination thereof.

[0023] The active material contained in the electrode slurry composition of the present invention varies depending on the type of electrode to be manufactured.

[0024] When the electrode slurry composition is used to manufacture a cathode, the active material can be selected from lithium-based layered transition metal oxides (as well as lithium-based metal chalcogenides or lithium-rich layered metal oxides and nickel-rich layered metal oxides), spinel oxides, polyanion compounds (LiFePO4, LiMnPO4, Li2MnSiO4, LiCoSiO4, etc.), and conversion cathode materials (e.g., transition metal halides, metal oxides, Li2S, etc.). In particular, the active material can be lithium iron phosphate (LiFePO4). Furthermore, the active material can be selected from the group consisting of lithium nickel manganese cobalt oxide (NMC, LiNiMnCoO2), lithium cobalt oxide (LCO, LiCoO2), lithium nickel cobalt aluminum oxide (NCA, LiNiCoAlO2), and lithium manganese oxide (LMO, LiMn2O4).

[0025] Additionally, the cathode active material can be selected from the group consisting of sodium-based layered oxides, such as sodium cobalt oxide (NaCoO) and sodium nickel oxide (NaNiO). These layered oxides can promote the intercalation of sodium ions. Other suitable cathode active materials include transition metal hexacyanoferrates or polyanionic compounds, such as sodium iron phosphate (NaFePO) and NaV(PO)F. These materials are known for their stability and safety.

[0026] When the electrode slurry composition of the present invention is used to manufacture an anode, the active material may be graphite, a silicon-based material, or a titanate (Li4Ti5O12 or Na2Ti3O7). The most common anode material is graphite, valued for its stability during the charging process and its ability to intercalate lithium ions. Lithium titanate (Li4Ti5O 12 ) is known for its fast charging capability and excellent safety, but suffers from low energy density. Silicon, especially silicon nanoparticles, has a much higher capacity than graphite, but suffers from structural degradation due to the volume expansion that accompanies lithium intercalation. Alternatively, the anode active material can be in the form of hard carbon or a metal alloy containing Sn or Sb.

[0027] The active material may be contained in an amount of 50 to 98 wt % based on the total weight of the electrode slurry composition, and particularly, the active material may be contained in an amount of 90 to 98 wt %.

[0028] The conductive binder may be contained in an amount of 0.1 to 25% by weight, preferably 0.2 to 10% by weight, and most preferably 0.5 to 5% by weight, based on the total weight of the electrode slurry composition.

[0029] The electrode slurry composition may have a solid content of 10% to 50%. In particular, the electrode slurry composition may have a solid content of 30% to 50%. It is desirable that the electrode slurry composition have as high a solid content as possible.

[0030] The conductivity of solution-processed n-type conductive polymers has been shown to be much higher compared to, for example, in situ polymerized PEDOT:PSS. Furthermore, solution-processed n-type conductive polymers are fluorine-free (compared to PVDF) and do not require toxic solvents such as 1-methylpyrrolidin-2-one (NMP). Finally, solution-processed n-type conductive polymers have shown improved mechanical stability and thermal resistance up to 225 °C after 1000 h compared to known binder materials such as PEDOT:PSS. This is important for maintaining electrode integrity during repeated charge-discharge cycling.

[0031] The solution-processed n-type conducting polymers, preferably free of side chains, can be doped with protons from the surface of the active material nanoparticles, resulting in a dual effect: improved conductivity through doping and improved coverage of the active material nanoparticles and beneficial bonding to the electron collector surface.

[0032] The electrode slurry composition described above may be used to manufacture an electrode for an energy storage device. Accordingly, the present invention relates to an electrode for use in an energy storage device. Such an electrode comprises an electron collector, an active material, and a conductive binder. The conductive binder comprises a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm.

[0033] It should be noted that the electrode according to the present invention can be either a cathode or an anode.

[0034] In particular, the n-type conductive polymer may not have side chains. Although the n-type conductive polymer contained in the electrode slurry composition may have side chains, the same n-type conductive polymer present in the electrode may not have side chains because the side chains may be removed by annealing the electrode slurry composition. On the other hand, if the n-type conductive polymer contained in the electrode slurry composition does not have side chains, the same n-type conductive polymer present in the electrode will also actually have no side chains. Furthermore, the solution-processed n-type conductive polymer may comprise a repeating unit containing a centrosymmetric benzene ring as the backbone, an active hydrogen, and at least one electron-withdrawing group at the benzylic position.

[0035] As mentioned above, the solution-processed n-type conducting polymer can be poly(benzodifurandione) (PBFDO), poly[(2,2′-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b′]difuran-2,6-dione] (PDADF), poly[(2,2′-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or mixtures thereof.

[0036] When the electrode of the present invention is used as a cathode, the active material may be LiVOPO4, LiCoO2, LiNiO2, LiNi 1-n Co n O2, LiNi 1-n-m Co n Al m O2, LiNi 1-n-m Co n Mn m O2, LiMn2O4, LiFePO4, and LiFe 1-n Mn n PO4, LiCoPO4, Li2FeP2O7, Li2FeSiO4, and combinations thereof. In particular, the active material can be lithium iron phosphate (LiFePO4).

[0037] The electron collector may be a metal selected from the group consisting of aluminum (Al), titanium (Ti), copper (Cu), and combinations thereof. In particular, the electron collector may be an aluminum foil.

[0038] The electrode may further comprise a dispersant and / or a non-conductive binder. The dispersant improves the dispersion and rheology of the slurry, while the non-conductive binder improves structural integrity and provides mechanical support.

[0039] The thickness of the conductive binder and active material on the electron collector can be from 5 μm to 500 μm, preferably from 10 μm to 300 μm, and most preferably from 20 μm to 200 μm.

[0040] Because the solution-processed n-type conducting polymers are preferably free of side chains, they can be doped with protons from the active material nanoparticle surface, resulting in a dual effect: improved conductivity through doping, and improved coverage and favorable bonding of the active material nanoparticles to the electron collector surface.

[0041] The present invention also relates to an energy storage device comprising an electrode as described above, in particular where the electrode disclosed above functions as a cathode.

[0042] The energy storage device according to the present invention may further include LiPF6 as an electrolyte solution and an anode containing an alkali metal.

[0043] The energy storage device can be of any type known in the art, such as a coin cell, a pouch cell, a cylindrical battery, or a battery pack, etc. The energy storage device of the present invention can be used in a variety of applications, such as in the electronics or automotive industries.

[0044] Finally, the present invention relates to a method for manufacturing an electrode for use in an energy storage device, such method comprising the steps of: (a) mixing an active material with a dispersing solution comprising a conductive binder comprising a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm, preferably at least 500 S / cm, thereby obtaining a slurry; (b) applying the slurry onto an electron collector, thereby obtaining the electrode; (c) drying the electrode; Includes:

[0045] The solution-processed n-type conductive polymer contained in the dispersion solution described above may be in the form of micelles with a diameter of less than 1 μm, preferably less than 0.5 μm, and more preferably less than 0.2 μm. The particle size can be easily confirmed by filtering the polymer solution through a 0.2 μm or 0.45 μm PE, Teflon, or PTFE filter, whereupon it can be observed that the solution remains colored, indicating that the polymer micelles have passed through the filter.

[0046] Step (b) may be carried out by any means commonly used in the art. In particular, step (b) may be carried out by bar coating. Alternatively, step (b) may be carried out by calendaring.

[0047] Step (c) may be carried out at a temperature between 100° C. and 200° C. for a period of between 30 minutes and 2 hours. Step (c) may be carried out under dynamic vacuum.

[0048] The method comprises the following steps: (d) homogenizing the slurry; may further comprise Here, the step (d) is carried out before the step (b).

[0049] Such step (d) may be carried out at a speed of 4000 to 10000 rpm for a period of 1 minute to 1 hour.

[0050] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0051] [Figure 1] The morphology of the reference benchmark LFP electrode is shown. [Figure 2] 1 shows the configuration of an n-LFP electrode according to the present invention. [Figure 3a] 1 shows the results of the electrochemical stability of the electrode according to the present invention. [Figure 3b]1 shows the results of the electrochemical stability of the electrode according to the present invention. [Figure 4] 1 shows a comparison of the performance of an electrode of the present invention with that of a reference electrode during one charge-discharge cycle at 0.2C. [Figure 5] 1 shows the performance of an electrode of the present invention during three charge-discharge cycles at 0.2C. [Figure 6a] 1 shows the results of reproducibility evaluation of the electrode of the present invention. [Figure 6b] 1 shows the results of reproducibility evaluation of the electrode of the present invention. [Figure 6c] 1 shows the results of reproducibility evaluation of the electrode of the present invention. [Figure 7] 1 shows the coulombic efficiency and specific discharge capacity of an electrode according to the invention compared to a reference electrode. [Figure 8a] 1 shows the thermal stability of solution-processed n-type conducting polymers used in electrodes according to the present invention. [Figure 8b] 1 shows the thermal stability of solution-processed n-type conducting polymers used in electrodes according to the present invention. [Figure 8c] 1 shows the thermal stability of solution-processed n-type conducting polymers used in electrodes according to the present invention. Specific Description of the Invention

[0052] As described above, the present invention provides an electrode slurry composition for the manufacture of electrodes used in energy storage devices. The electrode slurry composition includes an active material and a conductive binder, the conductive binder comprising a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm. The inventors surprisingly discovered that the n-type conductive polymer contained in the electrode slurry composition of the present invention functions as both a binder and a conductive additive, thereby eliminating the need for a conductive additive. The electrode slurry composition of the present invention may be prepared using a solvent with a lower environmental impact than conventional compositions. The n-type conductive polymer provides a perfluoroalkyl and polyfluoroalkyl substances (PFAS)-free alternative to the PVDF binder commonly used in battery slurries.

[0053] These and other advantages of the present invention are discussed in more detail below.

[0054] To evaluate the electrode slurry composition and electrode of the present invention, a reference electrode (also referred to as an LFP electrode) and an electrode of the present invention (also referred to as an n-LFP electrode) were prepared.

[0055] The electrode slurry composition for the reference electrode was prepared by dissolving PVDF 5130 (5 wt%) in DMSO with stirring. The solution was heated to 70°C to completely dissolve PVDF in DMSO. The active material in the form of LFP (90 wt%) and the conductive additive in the form of carbon black (5 wt%) were added to the PVDF dispersion solution, followed by homogenization at 3000 rpm for 5 minutes using an Ultraturrax T25 homogenizer. The reference electrode was prepared by bar coating the electrode slurry onto aluminum foil with a casting thickness of 50 μm. The resulting reference electrode was dried under dynamic vacuum at 120°C for 2 hours.

[0056] The electrode slurry composition of the present invention was prepared as follows: LFP active material was mixed with a conductive binder in the form of a dispersion of PBFDO in DMSO (1.56 wt %, N43, batch number 20231123) obtained from n-ink, to provide a 95:5 weight percent active material to conductive binder ratio.

[0057] The resulting electrode slurry composition was loaded into an Ultraturrax T25 homogenizer and mixed at 6000 to 8000 rpm for 20 minutes.

[0058] The homogenized electrode slurry composition was coated onto an aluminum foil to a casting thickness of 60 μm to obtain an electrode blank, which was then dried under dynamic vacuum at 120° C. for 2 hours.

[0059] The electrode compositions of the reference electrode and the electrode of the present invention are outlined in Table 1. [Table 1]

[0060] Circular electrodes with a diameter of 11 mm were punched from each dried electrode blank. The LFP electrodes were 12 ± 1 μm thick and weighed 1.7 ± 1 mg, and the n-LFP electrodes were 14 ± 1 μm thick and weighed 2.1 ± 1 mg.

[0061] Figures 1 and 2 show SEM images of the reference electrode and the electrode of the present invention, respectively. As shown in Figure 2, a good interface is formed between the aluminum foil and the coated n-LFP slurry. Additionally, a smooth matrix surrounding the LFP particles is visible, indicating that the LFP particles are uniformly coated with N43. Furthermore, N43 acts as a binder for the LFP particles.

[0062] To investigate the electrochemical stability and performance of the energy storage device of the present invention, coin cells were assembled in an argon-filled glove box using a 1 M LiPF electrolyte solution in carbonate solvent, a separator, and a metallic lithium counter electrode. Coin cells were prepared for both n-LFP and LFP electrodes. Three cells of each electrode type were assembled for electrochemical testing. These are designated LFP-S1, LFP-S2, and LFP-S3, and n-LFP-S1, n-LFP-S2, and n-LFP-S3, respectively.

[0063] To experimentally evaluate the electrochemical stability of N43 spin-coated on aluminum foil, cyclic voltammetry (CV) at 0.5 mV / s was used. The results are summarized in Figures 3a and 3b.

[0064] The CV of the N43 film between 2.5 and 4.5 V demonstrates that no irreversible oxidation or reduction occurs except during the first cycle (Figure 3a). This means that N43 does not degrade within this voltage operating window. This is an encouraging result, demonstrating that the conductive binder of the present invention can be used in most cathodes, including NMC systems.

[0065] As shown in Figures 3a and 3b, n-LFP is stable at 4.2 V vs. Li / Li. Stable behavior was also observed when the potential window was extended to 4.5 V vs. Li / Li. Furthermore, the conductive binder of the present invention exhibits advantageous capacity contribution.

[0066] The electrochemical performance of the energy storage device according to the present invention was evaluated at a rate of 0.2 C. The charge-discharge curves (first cycle) of the n-LFP electrode and the LFP electrode are shown in FIG.

[0067] A faradaic Li extraction from the LFP cathode occurs near 3.5 V during the charging process (solid-state like), resulting in a linear change in capacity. After this process, a small (less than 10%) capacitive charge accumulation occurs up to 4.2 V. During the discharging process, a faradaic lithiation reaction occurs at the cathode near 3.4 V, followed by a small capacitive discharge to 2.5 V.

[0068] As shown in Figure 4, the electrode of the present invention exhibits excellent performance for the first cycle of constant current charge / discharge at 0.2 C. The high capacity value indicates that the capacity of the n-LFP electrode is close to the practical capacity of the LFP electrode (150 mAh / g). Furthermore, it is demonstrated that N43 can function as both a binder and a conductive additive.

[0069] The electrochemical performance of the energy storage device of the present invention during cycling (charge and discharge) was evaluated by measuring the change in capacity with a change in voltage (U) at a rate of 0.2 C. The charge and discharge cycles are shown in Figure 5. As shown in Figure 5, similar behaviors are observed during different cycles, indicating the stability of the electrochemical behavior. Furthermore, the capacity increases during the first few cycles, indicating the improvement of the wettability of the electrode.

[0070] Next, we performed a reproducibility study on three cells equipped with n-LFP electrodes. The results are shown in Figures 6a-6c. These results are reproducible, with similar results obtained from three different cells. Similar behavior was also observed across different cycles, indicating the stability of the electrochemical behavior. Again, the capacity increased over the first few cycles, indicating improved wettability of the electrodes.

[0071] The stability of electrochemical performance over 10 cycles was evaluated for energy storage devices with LFP electrodes and n-LFP electrodes. Specific discharge capacity and coulombic efficiency were measured. The results are shown in Figure 7. As shown, stable electrochemical behavior was observed over 10 cycles for the three different n-LFP samples. The coulombic efficiency was close to 100%, reflecting high reversibility and the absence of parasitic reactions.

[0072] Figures 8a and 8b show the thermal stability of a solution-processed n-type conductive polymer, i.e., polybenzodifurandione (PBFDO), used in the electrodes of the present invention. As can be seen, PBFDO exhibits excellent thermal stability with little loss in conductivity up to 200°C. As confirmed in Figure 8c, the solution-processed n-type conductive polymer can be heat-resistant up to 225°C. The term "heat-resistant" means that the solution-processed n-type conductive polymer maintains conductivity in the film up to 225°C.

[0073] In summary, the electrode slurry composition of the present invention eliminates the need for conductive additives, uses a more environmentally friendly solvent, such as DMSO, instead of the commonly used NMP, and is shown to be PFAS-free. Furthermore, the n-LFP electrode exhibits uniform distribution of the conductive binder coating on the LFP particles. The capacity values ​​of the electrodes of the present invention are highly promising, approaching the practical capacity of LFP (150 mAh / g). The results are reproducible, with nearly identical results obtained from three different cells. The electrodes of the present invention exhibit stable electrochemical characteristics over 10 cycles for different n-LFP samples. Furthermore, the coulombic efficiency of the electrodes of the present invention is close to 100%, reflecting high reversibility.

[0074] While the present invention has been described with reference to various embodiments, those skilled in the art will recognize that modifications may be made without departing from the scope of the invention. The detailed description is to be considered as exemplary, and it is the appended claims, including all equivalents, that are intended to define the scope of the invention.

Claims

1. 1. An electrode for use in an energy storage device, the electrode comprising an electron collector, an active material, and a conductive binder, the conductive binder comprising a solution-processed n-type conducting polymer having a conductivity of at least 100 S / cm.

2. The electrode of claim 1 , wherein the n-type conductive polymer does not contain side chains.

3. 3. The electrode of claim 1 or 2, wherein the solution-processed n-type conducting polymer has thermal stability up to 225°C.

4. 4. The electrode of claim 1, wherein the solution-processed n-type conducting polymer comprises repeat units containing a centrosymmetric benzene ring as a backbone, an active hydrogen, and at least one electron-withdrawing group at a benzylic position.

5. 5. The electrode of any one of claims 1 to 4, wherein the solution-processed n-type conducting polymer is poly(benzodifurandione) (PBFDO), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof.

6. The active substance is LiVOPO ４ , LiCoO ２ , LiNiO ２ , LiNi １－ｎ Co ｎ O ２ , LiNi １－ｎ－ｍ Co ｎ Al ｍ O ２ , LiNi １－ｎ－ｍ Co ｎ Mn ｍ O ２ , LiMn ２ O ４ , LiFePO ４ and LiFe １－ｎ Mn ｎ P.O. ４ , LiCoPO ４ , Li ２ FeP ２ O ７ , Li ２ FeSiO ４ 6. The electrode of claim 1, wherein the electrode is selected from the group consisting of:

7. 7. The electrode of claim 1, wherein the electron collector is a metal selected from the group consisting of aluminum (Al), titanium (Ti), copper (Cu), lithium (Li), and combinations thereof.

8. 8. The electrode of claim 7, wherein the electron collector is an aluminum foil.

9. The electrode of any one of claims 1 to 8, wherein the electrode further comprises a dispersant and / or a non-conductive binder.

10. An energy storage device comprising the electrode according to any one of claims 1 to 9.

11. 11. The energy storage device of claim 10, wherein the electrode is a cathode.

12. LiPF as an electrolyte solution ６ and an anode comprising an alkali metal.

13. 1. An electrode slurry composition for the manufacture of an electrode for use in an energy storage device, the electrode slurry composition comprising an active material and a conductive binder, the conductive binder comprising a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm.

14. The electrode slurry composition according to claim 13 , wherein the n-type conductive polymer does not contain a side chain.

15. 15. The electrode slurry composition according to claim 13 or 14, wherein the solution-processed n-type conductive polymer comprises a repeating unit containing a centrosymmetric benzene ring as a backbone, an active hydrogen, and at least one electron-withdrawing group at a benzylic position.

16. 16. The electrode slurry composition according to any one of claims 13 to 15, wherein the solution-processed n-type conductive polymer is poly(benzodifurandione) (PBFDO), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid)-co-3,7-dihydrobenzo[1,2-b:4,5-b']difuran-2,6-dione] (PDADF), poly[(2,2'-(2,5-dihydroxy-1,4-phenylene)diacetic acid) (PDADF-P), or a mixture thereof.

17. The active substance is LiVOPO ４ , LiCoO ２ , LiNiO ２ , LiNi １－ｎ Co ｎ O ２ , LiNi １－ｎ－ｍ Co ｎ Al ｍ O ２ , LiNi １－ｎ－ｍ Co ｎ Mn ｍ O ２ , LiMn ２ O ４ , LiFePO ４ and LiFe １－ｎ Mn ｎ P.O. ４ , LiCoPO ４ , Li ２ FeP ２ O ７ , Li ２ FeSiO ４ The electrode slurry composition according to any one of claims 13 to 16, wherein the electrode slurry composition is selected from the group consisting of:

18. 18. The electrode slurry composition according to any one of claims 13 to 17, wherein the active material is present in an amount of 50 to 98 wt%.

19. 19. An electrode slurry composition according to any one of claims 13 to 18, wherein the conductive binder is present in the composition in an amount of 0.1 to 25 wt%, preferably in an amount of 0.2 to 10 wt%, and most preferably in an amount of 0.5 to 5 wt%.

20. The electrode slurry composition according to any one of claims 13 to 19, wherein the electrode slurry composition has a solids content of 10 to 50%.

21. 1. A method of manufacturing an electrode for use in an energy storage device, the method comprising the steps of: (a) mixing an active material with a dispersing solution comprising a conductive binder comprising a solution-processed n-type conductive polymer having a conductivity of at least 100 S / cm, thereby obtaining a slurry; (b) applying the slurry onto an electron collector, thereby obtaining the electrode; (c) drying the electrode; A manufacturing method comprising:

22. The method comprises the steps of: (d) homogenizing the slurry; further comprising 22. The method of claim 21, wherein step (d) is performed before step (b).

23. 23. The method of claim 21 or 22, wherein step (b) is carried out by bar coating.

24. 24. The method of any one of claims 21 to 23, wherein step (c) is carried out at a temperature of from 100°C to 200°C for a period of from 30 minutes to 2 hours.

25. 25. The method of any one of claims 21 to 24, wherein step (d) is carried out at 4000 to 10000 rpm for a period of 1 minute to 1 hour.

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