Electrode binder including cationic semi-IPN polymer, electrode and cell including this binder

Abstract

The present invention relates to an electrode binder containing a cationic, semi-interpenetrating network polymer, and to electrodes and batteries containing such a binder. The electrode binder of the present invention can improve both the physical properties (dispersion, flexibility, and adhesion) and the electrochemical properties (performance, charge / discharge, and lifetime) of the electrodes.

Description

BACKGROUND

[0001] The present invention relates to an electrode binder comprising a cationic, semi-interpenetrating network polymer, as well as to an electrode and a battery incorporating such a binder.

[0002] The promising potential of future innovative electronic devices, electric vehicles, and grid-scale energy storage systems is driving the continued demand for high-energy-density lithium batteries. In addition to ongoing research into advanced active electrode materials, the development of high-area capacitance (C / A) electrodes is gaining momentum as a simple and scalable approach to increasing the energy density of batteries without the need to synthesize new active electrode materials. This process is considered an effective strategy for achieving higher energy densities in batteries.

[0003] To achieve electrodes with high C / A value (where C / A = mass per unit area (M / A) × specific capacity of the active electrode material (C sp )), it is essential to maximize M / A while simultaneously increasing C spat a stable level. However, conventional electrodes struggle to meet these requirements due to physical challenges with thick electrodes and electrochemical issues related to uneven charge transfer across the electrode. Particularly during the fabrication of thick electrodes, drying of process solvents such as N-methyl-2-pyrrolidone (NMP) and water often leads to cracking and detachment from the metal current collector, limiting the increase in M / A values. Furthermore, with increasing electrode thickness, charge transfer within the electrode active material tends to become uneven along the thickness direction, resulting in slower reaction rates and a subsequent loss of Csp values.

[0004] To overcome these challenges, previous research on high C / A electrodes has largely relied on mechanical pressing and fabrication techniques such as freeze-drying, infiltration, and phase inversion. While these techniques have improved apparent M / A values, they often failed to significantly reduce the C sp could not be maintained, thus hindering the achievement of meaningful C / A values. Furthermore, these physical architecture-based approaches often require complex and costly fabrication processes, making it difficult to scale the research results beyond the laboratory level. Therefore, to develop practically scalable high C / A ratio electrodes, it is essential to explore new material chemistries compatible with commercial slip-cast electrode fabrication processes. Patent Document 1. Korean Registered Patent 10-2661643

[0005] The present invention was conceived to address the above-mentioned challenges. The primary objective of the invention is to provide a binder for secondary battery electrodes that includes a cationic semi-interpenetrating network (semi-IPN) polymer.

[0006] The present invention also aims to provide an electrode including the above-mentioned binder for secondary battery electrodes.

[0007] Furthermore, the present invention aims to provide a secondary battery including the above-mentioned electrode.

[0008] Furthermore, the present invention aims to provide an apparatus including the above-mentioned battery, the apparatus being selected from communication apparatuses, transportation apparatuses, and energy storage devices.

[0009] Furthermore, the present invention aims to provide a method for producing a secondary battery electrode, which includes: (a) preparing an electrode slurry by mixing a binder and an electrode active material in a solvent; and (b) applying the electrode slurry to obtain an electrode. The binder used in this method comprises a cationic monomer, a crosslinkable monomer having multifunctional groups, and a linear polymer.

[0010] One aspect of the present invention relates to a binder for secondary battery electrodes including a cationic semi-interpenetrating network (semi-IPN) polymer.

[0011] Another aspect of the present invention relates to an electrode including the above-mentioned binder for secondary battery electrodes.

[0012] Yet another aspect of the present invention relates to a secondary battery comprising the electrode.

[0013] Yet another aspect of the present invention relates to a device comprising the battery, wherein the device is selected from the group consisting of a communication device, a transport device, and an energy storage device.

[0014] Another aspect of the present invention relates to a method for producing an electrode for a secondary battery, comprising: (a) preparing an electrode slurry by adding a binder and an electrode active material to a solvent; and (b) obtaining an electrode by coating the electrode slurry, wherein the binder comprises a cationic monomer, a polyfunctional crosslinkable monomer, and a linear polymer.

[0015] The electrode binder containing the cationic semi-interpenetrating network polymer of the present invention can improve the physical properties of the electrode (such as dispersibility, toughness and adhesion) as well as the electrochemical properties (such as power, charging and cycle life properties).

[0016] The effects of the present invention are not limited to those mentioned above. It should be understood that the effects of the present invention include all effects that can be derived from the following description.

[0017] Fig.1 is a schematic diagram showing the chemical formula of the cationic semi-interpenetrating network polymer (c-IPN) according to an embodiment of the present invention, illustrating the superiority of a cathode having a high areal capacitance (C / A) according to an embodiment of the present invention compared to a control cathode having a low areal capacitance (C / A) at the same cell capacity, and a schematic diagram showing the control of electrostatic phenomena by the binder according to an embodiment of the present invention.

[0018] The Fig. 2A to 2D illustrate the following: (2A) a graph showing the specific energy of the NCM811 battery and the specific capacity of the electrode active material (C sp) when varying the basis weight (M / A) of the electrode cathode prepared in Example 1 (c-IPN) of the present invention; (2B) a photograph of a double-layer pouch cell using the electrode cathode prepared in Example 1 (c-IPN) (C / A = 18 mAh cm -2 ); (2C) an X-ray micro-computed tomography image showing the cross-sectional structure of the cell; and (2D) the cycling performance at 25 °C with a charge / discharge current density of 0.9 mA cm -2 / 1.8 mA cm -2 and a voltage range of 3.0 to 4.4 V.

[0019] Fig. 3 is a photograph of a double-layer pouch-type full cell with the electrode cathode (C / A = 18 mAh cm -2 ) prepared in Example 1 (c-IPN) of the present invention.

[0020] The Fig. 4A and Fig.4B shows (A) the constant current charge / discharge profiles at the 2nd, 40th, and 50th cycles and (B) the corresponding dQ / dV diagrams of the double-layer pouch cell using the electrode cathode prepared in Example 1 (c-IPN) of the present invention.

[0021] Fig. Figure 5 shows a comparison of the specific energy and energy density between the high energy density pouch cell using the electrode cathode prepared in Example 1 (c-IPN) of the present invention and the previously described high energy density pouch cells.

[0022] The Fig.6A to 6C illustrate the constant current charge / discharge profiles from Experimental Example 1 of the present invention for the following cells: (A) Cell No. 1 (cycled cathode || fresh liquid electrolyte with a new Li-metal anode), (B) Cell No. 2 (cycled cathode || cycled liquid electrolyte with a new Li-metal anode), and (C) Cell No. 3 (cycled cathode in fresh liquid electrolyte || cycled Li-metal anode).

[0023] Fig. Figure 7 shows the 1H nuclear magnetic resonance (NMR) spectrum and chemical structure of 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI) synthesized in Example 1 of the present invention.

[0024] Fig.Figure 8 illustrates the electrochemical stability window measured by linear sweep voltammetry (LSV) for TMPTA / VAI-TFSI and trimethylolpropane triacrylate (TMPT333999A) prepared in Example 1 of the present invention.

[0025] The Fig. 9A and Fig. 9B show (A) the discharge rate performance and (B) the critical crack thickness (CCT) and critical delamination thickness (CDT) of the cathode (M / A = 65 mg cm -2 ) using TMPTA / VAI-TFSI with varying composition ratios as prepared in Example 1 of the present invention.

[0026] The Fig.10A to 10D show, for the electrode slurry (30% solids content) prepared in Example 1 (c-IPN), Comparative Example 1 (n-IPN), and Comparative Example 2 (PVDF) of the present invention, the following: (A) surface tension measured using the pendant drop method, (B) absolute zeta potential, (C) micrographs, and (D) laser scanning confocal microscopy (LSCM) images of the surface topography of electrodes prepared from the high M / A (= 50 mg cm -2 ) in Example 1 (c-IPN), Comparative Example 1 (n-IPN) and Comparative Example 2 (PVDF).

[0027] The Fig. 11A to 11B show photographs of the pendant drop tensiometer used to measure the surface tension of the electrode slurry prepared in Comparative Example 2 (PVDF) (A), Comparative Example 1 (n-IPN) (B), and Example 1 (c-IPN) (C) of the present invention.

[0028] The Fig. Figures 12A to 12C show the laser scanning confocal microscopy (LSCM) images of the surface topography of the low M / A (= 26 mg cm -2 ) prepared in Comparative Example 2 (PVDF) (A), Comparative Example 1 (n-IPN) (B) and Example 1 (c-IPN) (C) of the present invention.

[0029] The Fig. 13A to 13H illustrate the following: (A) Fourier transform infrared (FT-IR) spectra of c-IPN films before and after thermal crosslinking. B) Stress-strain curves of PVDF, n-IPN, and c-IPN films. (C) Adhesive strength measured by 180° peel tests as a function of M / A for electrodes prepared in Comparative Example 1 (PVDF), Comparative Example 2 (n-IPN), and Example 1 (c-IPN) of the present invention. (D) A micrograph of the electrode (M / A = 50 mg cm -2) prepared in Comparative Example 1 (PVDF). (E) A micrograph of the electrode (M / A = 96 mg cm -2 ) prepared in Example 1 (c-IPN). (F) Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) images of the cross-section of the electrode prepared in Example 1 (c-IPN) (M / A = 96 mg cm -2 ). G) Graph showing the thickness and electrode density (ρ) as a function of M / A for the electrode prepared in Example 1 (c-IPN) after roll pressing. (H) A graph comparing the electrode density as a function of C / A for the electrode prepared in Example 1 (c-IPN) with previously described high M / A electrodes.

[0030] The Fig. Figures 14A to 14D show differential scanning calorimetry (DSC) profiles representing the glass transition temperature (Tg) of (A) pristine PVDF films, (B) pristine TMPTA / VAI-TFSI cross-linked copolymer films, and (C, D) c-IPN films.

[0031] The Fig. Figures 15A to 15C illustrate the bond strength between the active electrode layer and the Al current collector for electrodes with different M / A values ​​fabricated using (A) PVDF, (B) n-IPN, and (C) c-IPN.

[0032] The Fig. Figures 16A to 16F illustrate the following: (A) Constant current charge / discharge profiles at 25 °C as a function of cathode M / A for a cell using the cathode || Li-metal anode prepared in Example 1 (c-IPN) of the present invention. A graph showing the specific capacity (C sp) as a function of M / A at a discharge rate of 0.1 C for cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN). (C) A graph of specific energies as a function of M / A for cells using cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN). (D) A light micrograph of the cross-section of the cathode obtained after dissecting a cell discharged at a current density of 1.1 mA cm -2 charged to 4.4 V, using the cathode (M / A = 65 mg cm -2 ) prepared in Example 1 (c-IPN). (E) Raman spectra and the intensity ratio of Eg / A1g for the upper and lower regions of the cathode prepared in Comparative Example 1 (n-IPN). (E) Raman spectra and the intensity ratio of Eg / A1g for the upper and lower regions of the cathode prepared in Example 1 (c-IPN).

[0033] The Fig. 17A and Fig. 17B show the charge / discharge profiles at constant current as a function of the cathode M / A (= 26 to 96 mg cm -2 ) for cells combining Li-metal anodes with cathodes prepared in (A) Comparative Example 1 (n-IPN) and (B) Example 1 (c-IPN) of the present invention. The profiles were measured at charge / discharge current rates of 0.05 C / 0.1 C within a voltage range of 3.0 to 4.4 V.

[0034] The Fig. Figures 18A to 18C illustrate the following: (A) A graph showing the discharge rate performance (expressed as Csp) as a function of M / A for cells combining Li-metal anodes with cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) of the present invention. (B) The constant current charge / discharge profiles at discharge current rates of 0.05 C (= 0.68 mA cm -2 ) to 0.5 C (= 6.75 mA cm -2) for a cell using a cathode with high M / A (= 65 mg cm -2 ) prepared in Comparative Example 1 (n-IPN). (B) The constant current charge / discharge profiles at discharge current rates of 0.05 C (= 0.68 mA cm -2 ) to 0.5 C (= 6.75 mA cm -2 ) for a cell using a cathode with high M / A (= 65 mg cm -2 ) prepared in Example 1 (c-IPN).

[0035] Fig. 19 shows a light micrograph of the cross section of the cathode (M / A = 65 mg cm -2 ) prepared in Comparative Example 1 (n-IPN) of the present invention.

[0036] The Fig. 20A and Fig. 20B shows the Raman spectra and the intensity ratio (Eg / A1g) for the upper and lower regions of cathodes with low M / A (26 mg cm -2 ), after being charged with a current rate of 0.2 C (= 1.1 mA cm -2). The cathodes were prepared (A) in Comparative Example 1 (n-IPN) and (B) in Example 1 (c-IPN) of the present invention.

[0037] Fig. Figure 21 shows the comparison of electrical conductivity (measured with a four-point probe station) as a function of M / A for cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) of the present invention.

[0038] The Fig. 22A to 22G illustrate the following: (A) FT-IR spectra of cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) when in contact with a liquid electrolyte (1 M LiPF6 in EC / DEC = 1 / 1 (v / v)). (B) Results of the 7Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy at the binder-electrolyte interface for cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN). (C) Radial distribution function (RDF) profile of the P atom in PF6 - . (D) Radial distribution function (RDF) profile of the Li atom. (E) Arrhenius diagram of the ionic conductivity in electrolyte-filled pores for cathodes (M / A = 65 mg cm -2 ), prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN). (F) Diagram showing the internal resistance (R innen ) and D Li+ as a function of the discharge voltage for cathodes (M / A = 65 mg cm -2 ) prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN). (G) A schematic diagram illustrating the role of the binder according to one embodiment of the present invention.

[0039] Fig.Figure 23 shows the inversion recovery diagrams obtained from the 7 Li-mAS NMR spectra were obtained from cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) of the present invention.

[0040] The Fig. Figures 24A to 24C illustrate the following: (A) Nyquist diagrams for symmetric cells (electrode || electrode) containing fully lithiated cathodes with high M / A (= 65 mg cm -2 ) prepared in Comparative Example 1 (n-IPN). (A) Nyquist plots for symmetric cells (electrode || electrode) containing fully lithiated cathodes with high M / A (= 65 mg cm -2 ) prepared in Example 1 (c-IPN). (C) The equivalent circuit model using the generalized Warburg element with finite-length open-circuit termination (WO, Warburg Open).

[0041] The Fig. 25A to 25B show for cathodes with high M / A (= 65 mg cm -2) prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN): (A) The profiles of the galvanostatic intermittent titration technique (GITT) under repeated current pulses at a discharge current rate of 0.1 C (= 1.35 mA cm -2 ). (B) The GITT profiles, specifically highlighting the discharge phase.

[0042] The Fig. 26A and Fig. 26B illustrate the following: (A) The weight change of cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) after immersion in a liquid electrolyte (1M LiPF6 in EC / DEC = 1 / 1(v / v)) for 2 hours. (B) Images of the cathode prepared in Example 1 (c-IPN) before (left) and after (right) electrolyte absorption.

[0043] The Fig. Figures 27A to 27G illustrate the following: (A) Cycle performance of Li-metal full cells using cathodes (M / A = 65.0 mg cm -2 ) prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) of the present invention. (B) X-ray photoelectron spectroscopy (XPS) depth profiles of cycled cathodes prepared in Comparative Example 1 (n-IPN). (C) XPS depth profiles of cycled cathodes prepared in Example 1 (c-IPN). (D) FT-IR spectra of cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) in liquid electrolyte (1M LiPF6 in EC / DEC = 1 / 1(v / v)), with emphasis on the carbonyl stretching vibration assigned to the EC solvent. (E) Diagram showing the relative ratio of Li +Solvation structures within the liquid electrolyte of cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). (F) HOMO (Highest Occupied Molecular Orbital) energy levels of the main Li + Solvation structures in cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). (G) Binding energies between the electrolyte components (PF6 - and EC) and Li + in cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN).

[0044] The Fig. 28A and Fig. 28B illustrates the constant current charge / discharge profiles at the first, 50th, and 100th cycles for Li-metal full cells using cathodes prepared in (A) Comparative Example 1 (n-IPN) and (B) Example 1 (c-IPN) of the present invention.

[0045] The Fig.Figures 29A to 29C illustrate the following: (A) Nyquist diagrams from the first cycle of Li-metal full cells using cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) of the present invention. (B) Nyquist diagrams from the 50th cycle of the same cells. (C) The equivalent circuit used to fit the Nyquist diagrams.

[0046] The Fig. 30A to 30C depict the X-ray photoelectron spectroscopy (XPS) profiles for cycled NCM811 cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) of the present invention, showing the following: (A) C1s profile, (B) F1s profile and (C) O1s profile.

[0047] The Fig.Figures 31A to 31E show the TOF-SIMS depth profiling of the cathodes after cycling in (A) Comparative Example 1 (n-IPN) and (B) Example 1 (c-IPN), as well as the TOF-SIMS depth profiles of (C) LiF2-, (D) Li2CO3-, and (E) C2F-.

[0048] The Fig. 32A and Fig. 32B show the radial distribution function (RDF) profiles and the coordination numbers (CN; between Li + and solvent in the liquid electrolyte) at the binder-electrolyte interfaces (EC(A) and DEC(B)) of the cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN).

[0049] The Fig. 33A and Fig. 33B show the radial distribution function (RDF) profiles (A) and the coordination numbers (CN) (B) between Li + and PF6- in the liquid electrolyte at the binder-electrolyte interface and in the bulk electrolyte of the cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN).

[0050] The Fig. 34A and Fig. 34B show the HOMO (highest occupied molecular orbital) energy levels and the relative ratios of the solvation structures of Li + in the liquid electrolyte (EC / DEC with 1 M LiPF6 = 1 / 1 (v / v)) for the cathodes prepared in Comparative Example 1 (n-IPN) (A) and in Example 1 (c-IPN) (B).

[0051] The Fig. 35A to 35H show the following for the cathodes prepared in Comparative Example 1 (n-IPN) (A, C, E, G) and Example 1 (c-IPN) (B, D, F, H): cross-sectional scanning electron microscopy (SEM) images of cycled NCM811 (A, B), high resolution transmission electron microscopy (HR-TEM) images (CF), and fast Fourier transform (FFT) patterns (G, H).

[0052] The Fig. 36A and Fig.36B shows cross-sectional scanning electron microscopy (SEM) images of cycled NCM811 particles in the cathodes prepared in Comparative Example 1 (n-IPN) (A) and Example 1 (c-IPN) (B).

[0053] The Fig. 37A and Fig. 37B illustrate the following: (A) Photographs of the cathodes fabricated in Comparative Example 1 (PVdF), Example 1 (TMPTA), Example 2 (TPPTA), and Example 3 (ETPTA), along with critical crack thickness (CCT) and critical delamination thickness (CDT) plots. (B) Diagrams showing the volume resistivity (R bulk ) and the interface resistance (R interfacial ) of the cathodes prepared in Example 1 (TMPTA) and Example 3 (ETPTA).

[0054] The advantages and features of the present invention, as well as methods for achieving them, will become more apparent with reference to the detailed examples described below and the accompanying drawings. However, the invention is not limited to the embodiments disclosed herein; it may be embodied in various forms. These embodiments are provided to ensure that the disclosure of the invention is complete and to fully inform those skilled in the art of the scope of the invention. The invention is defined exclusively by the claims.

[0055] In describing the present invention, detailed explanations of related art may be omitted if they are believed to unnecessarily obscure the gist of the invention. When terms such as "comprises," "includes," or "is / are" are used in this description, it should be assumed that other parts or elements may be added unless expressly stated otherwise. Furthermore, the terms "comprise" or "comprise" are intended to specify the presence of features, numbers, steps, components, or combinations thereof as stated in the description and should not be construed to preclude the presence or possibility of additional features, numbers, steps, components, or combinations thereof.When a component is expressed in the singular, it should be understood that it also includes the plural, unless expressly stated otherwise.

[0056] One aspect of the present invention is to provide a binder for secondary battery electrodes comprising a cationic semi-interpenetrating network (semi-IPN) polymer.

[0057] The cationic semi-interpenetrating network (semi-IPN) polymer refers to a polymer in which a network polymer and a linear polymer are mixed together.

[0058] Fig.Figure 1 shows the following: 1. The chemical formula of the cationic semi-interpenetrating network polymer (c-IPN) according to an embodiment of the present invention. 2. A schematic diagram illustrating the superiority of a cathode with a high areal capacitance (C / A) according to an embodiment of the present invention compared to a control cathode with a lower areal capacitance (C / A) at the same cell capacity. 3. A schematic diagram illustrating the control of electrostatic phenomena by the binder according to an embodiment of the present invention.

[0059] As in Fig.As shown in Figure 1, the binder for secondary battery electrodes according to the present invention, which contains the cationic semi-interpenetrating network polymer (c-IPN), enables the production of cathodes with high areal capacitance (C / A). It can interact with the liquid electrolyte to increase the mobility of cations while fixing the corresponding anions. In addition, the binder can retain metal ions (Li + ) evenly throughout the electrode through electrostatic repulsion while facilitating the free movement of these metal ions, thereby inducing an increase in ionic conductivity in the electrode and contributing to improved performance and charging properties of the electrode.

[0060] The network polymer can be obtained by polymerizing a cationic monomer and a multifunctional crosslinking monomer.

[0061] The cationic monomer refers to a monomer that possesses a cationic group, and the network polymer will therefore include cationic groups in its main chain.

[0062] In the present invention, by using a network polymer polymerized from a cationic monomer that is not a neutral monomer or polymer but possesses a cationic group, the cationic network polymer acts as a surfactant. This enhances the electrostatic repulsion with electrode components, alleviates the internal stress due to solvent evaporation, and improves the dispersion state of the electrode slurry. Combined with the mechanical strength of the IPN structure, it also helps suppress cracking in the dried electrode, enabling the production of electrodes with a uniform topology and a high M / A ratio.

[0063] The cationic group may be selected from the group consisting of imidazolium, pyridinium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isoauronium, thiouronium, piperidinium, pyrazolium, methylium and morpholinium groups, with imidazolium groups being preferred, and even more preferred is the 1-vinyl-3-allylimidazolium group.

[0064] In particular, imidazolium, pyridinium, pyrrolidinium, guanidinium, piperidinium, and pyrazolium groups are preferable due to their high oxidation stability, which allows for stable use in the anode. Furthermore, cationic groups exhibit decreasing cationicity in the order of imidazolium, pyridinium, ammonium, and phosphonium. Therefore, if the cationic group is imidazolium, it can exhibit higher cationic properties, making them more preferable. Furthermore, imidazolium groups offer not only high cationic properties but also dimensional stability, which can increase by at least 1.2 times compared to other cationic groups, making them even more desirable.

[0065] If the cationic group includes an ammonium group, it can be written as *-NR a R b -*, where R a and R bare each independently hydrogen or C1 to C110 alkyl groups. In particular, R a and R b independently of one another C1 to C4 alkyl groups.

[0066] In addition, the cationic group can fix the anions of the liquid electrolyte by electrostatic attraction, while exhibiting electrostatic repulsion with metal ions (Li + ). This allows the free movement and uniform distribution of metal ions (Li + ) in the electrode, creating a stable cathode-electrolyte interface (CEI) in the electrode.

[0067] The cationic monomer may include a counterion for the cationic group, and this counterion may be selected from the group consisting of BF4-, B(CN)4-, CH3BF3-, CH2CHBF3-, CF3BF3-, C2F5BF3-, n-C3F7BF3-, n-C4F9BF3-, PF6-, CF3CO2-, CF3SO3-, N(SO2CF3)2- (TFSI-), N(COCF3)(SO2CF3)-, N(SO2F)2-, N(CN)2-, C(CN)3-, SCN-, and SeCN-. Preferably, the counterion is N(SO2CF3)2- (TFSI-).

[0068] The most preferred cationic monomer is 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI).

[0069] The multifunctional crosslinking monomer refers to a monomer having at least two or more polymerizable functional groups.

[0070] When a readily polymerizable monomer with only one polymerizable functional group is used instead of a multifunctional crosslinking monomer, the resulting polymer is linear rather than crosslinked, even when polymerized with the cationic monomer. As a result, no cationic semi-interpenetrating network (semi-IPN) polymer is formed, resulting in a significant reduction in toughness and causing significant fracture damage during thin-film electrode fabrication.

[0071] The multifunctional crosslinking monomer may comprise one or more selected from the group consisting of acrylic, conjugated diene, alkene, diol, fatty acid, amino acid, hydroxy acid, ester, lactone, carbonate, cyclic ether, lactam, and their derivatives.

[0072] The polymerizable functional groups can be selected from the group consisting of acrylate, methacrylate, vinyl and thiol groups, with acrylate groups being particularly preferred.

[0073] Specific examples of crosslinkable monomers containing a polyfunctional group with two polymerizable functional groups may include ethylene glycol diacrylate (EGDMA), triethylene glycol diacrylate (TEGDA), polyethylene glycol diacrylate (PEGDA), and 1,6-hexanediol diacrylate (HDDA).

[0074] Specific examples of crosslinkable monomers containing a polyfunctional group with three polymerizable functional groups may include ethoxylated trimethylolpropane triacrylate (ETPTA), trimethylolpropane propoxylate triacrylate (TPPTA), pentaerythritol triacrylate (PETA), and trimethylolpropane triacrylate (TMPTA). Especially, when three or more polymerizable functional groups are present, the linear polymer is tightly bound in the cationic semi-interpenetrating network polymer (semi-IPN), and even after electrochemical cycling, loss of the linear polymer cannot be observed at all.

[0075] The crosslinking monomer is preferably selected from the group consisting of pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA), with trimethylolpropane triacrylate (TMPTA) being particularly preferred.

[0076] If the crosslinking monomer is selected from the group consisting of pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA), it is preferable because it provides excellent modulus of the electrode, ensuring that the electrode does not deform during the electrode rolling process.

[0077] In contrast, when the multifunctional crosslinking monomer is trimethylolpropane propoxylate triacrylate (TPPTA) with a higher molecular weight, a reduction in the modulus of the electrode is observed, leading to greater delamination of the electrode layer during rolling.

[0078] Especially when the multifunctional crosslinking monomer is trimethylolpropane triacrylate (TMPTA), the binder used for secondary battery electrodes retains its mechanical properties even after prolonged cycling under high-temperature conditions. This property makes it particularly advantageous.

[0079] The network polymer can be obtained by polymerizing the cationic monomer and the multifunctional crosslinking monomer in a weight ratio of 0.8 to 7:1, preferably 1.2 to 5:1, more preferably 1.5 to 3:1, and most preferably 1.7 to 2.5:1.

[0080] If the cationic monomer is used in a larger amount so that the weight ratio is outside the above range, the mechanical properties of the electrode may deteriorate rapidly, and if the crosslinkable monomer containing the multifunctional group is used in an excessive amount, the electrochemical performance may deteriorate.

[0081] In particular, when the cationic monomer and the multifunctional crosslinking monomer are polymerized in a weight ratio of 1.2 to 5:1, with the cationic monomer present in excess, the electrode containing the binder for secondary battery electrodes exhibits a significant improvement in high-rate charge and discharge characteristics. This makes it particularly desirable.

[0082] The network polymer can be represented by the following chemical formula 1:

[0083] In Chemical Formula 1, n and m represent the degree of polymerization for each monomer unit, where n is an integer from 1 to 400, m is an integer from 1 to 200, and n:m is preferably 1:1 to 2:1.

[0084] In particular, the binder for a secondary battery electrode of the present invention contains the linear polymer, thereby improving the physical properties of the electrode, particularly its toughness, which contributes to reducing electrode cracks (breakages) during drying and enables the physical production of a thick electrode.

[0085] The linear polymer can be selected from the group consisting of cellulose-based polymers, acrylic-based polymers, and fluorine-containing polymers. Preferably, the linear polymer is a fluorine-containing polymer.

[0086] Specific examples of cellulose-based polymers are carboxymethylcellulose (CMC), methylcellulose (MC), hydroxypropylcellulose (HPC), methylhydroxypropylcellulose (MHPC), ethylhydroxyethylcellulose (EHEC), methylethylhydroxyethylcellulose (MEHEC) and cellulose gum.

[0087] Specific examples of acrylic polymers are polyacrylamide, poly(methacrylic acid), poly(methyl acrylate), poly(methyl methacrylate), poly(acrylic acid), polyacrylonitrile.

[0088] In particular, when the linear polymer is a fluorine-containing polymer, it exhibits excellent chemical stability, especially oxidation stability. This leads to a significant improvement in reducing the deposition of impurities due to side reactions at the interface between the active cathode material.

[0089] The fluorine-containing polymer may be at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), a copolymer (PVdF-HFP) of polyvinylidene fluoride-hexafluoropropylene, and a copolymer (PVdF-TFE) of polyvinylidene fluoride-tetrafluoroethylene.

[0090] The linear polymer may be contained in an amount of 45 to 100 parts by weight, preferably 50 to 90 parts by weight, and more preferably 55 to 70 parts by weight, based on 100 parts by weight of the network polymer.

[0091] If the linear polymer is used in less than 45 parts by weight relative to 100 parts by weight of the network polymer, the adhesive properties may be reduced. Conversely, if the linear polymer is used in more than 100 parts by weight relative to 100 parts by weight of the network polymer, the effectiveness of the network polymer may be reduced.

[0092] According to a preferred embodiment of the present invention, the network polymer is 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI), and the linear polymer is polyvinylidene fluoride (PVdF). When the electrode containing these components according to the preferred embodiment of the present invention is subjected to accelerated durability testing using conventional methods, it was confirmed that neither the current collector nor the electrode-active material applied to the current collector nor the binder coating is subject to deformation, cracking, or wrinkling.

[0093] According to another preferred embodiment of the present invention, the network polymer is obtained by polymerizing the cationic monomer and the multifunctional crosslinking monomer in a weight ratio of 1.7 to 2.5:1, and the linear polymer may be present in an amount of 55 to 70 parts by weight, based on 100 parts by weight of the network polymer. It has been confirmed that, when all specified weight ranges are maintained according to this preferred embodiment, the electrode exhibits particularly superior performance, with negligible heat generation due to short circuits in the penetration safety rating using conventional methods.

[0094] A polymerization initiator can be used for polymerization.

[0095] The initiator may be a peroxide-based initiator selected from the group consisting of benzoyl peroxide (BPO), dicumyl peroxide, dibutyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-3,3,5-trimethylcyclohexane, 3,1,3-bis(t-butylperoxyisopropyl)benzene, n-butyl 4,4-bis(t-butylperoxy)valerate, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and t-butyl perbenzoate lauryl peroxide.

[0096] In a preferred embodiment of the present invention, the cationic monomers may contain both 1-(vinylbenzyl)trimethylammonium chloride and 2-(1-methyl-1-(4-nitrobenzyl)piperidinium chloride. Although no specific experimental results are explicitly stated in this description, experiments were conducted in which the types and combinations of cationic monomers were varied to prepare electrodes. The cells prepared with these electrodes were heated to measure the temperature at which a fire or explosion occurred. It was observed that in the presence of both 1-(vinylbenzyl)trimethylammonium chloride and 2-(1-methyl-1-(4-nitrobenzyl)piperidinium chloride, the temperature at which a fire or explosion occurred was at least 20% higher than in cases where one or both of these monomers were absent. This indicates a significant increase in thermal stability.

[0097] In a preferred alternative embodiment of the present invention, the cationic monomers may include both 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI) and 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride. It was observed that, when using both 1-VAI-TFSI and 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride, electrodes prepared with these monomers could be wound around a 1 mm diameter stainless steel cylinder and subjected to a bending test by winding and unwinding the cylinder five times without any cracks or breaks occurring on the electrode surface. This indicates that the material has excellent flexural strength.

[0098] In contrast, in the absence of ① VAI-TFSI or ② 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride, significant cracks and fractures occurred after only a single winding and unwinding cycle with a 1 mm diameter cylinder. Even when the cylinder diameter was increased to 5 mm, cracks and fractures were still observed, indicating low flexibility.

[0099] The other aspect of the present invention relates to the provision of an electrode including a binder for secondary battery electrodes.

[0100] In the electrode, the binder for secondary battery electrodes may be contained in an amount of 1 to 10 parts by weight, preferably 2 to 8 parts by weight, and more preferably 3 to 7 parts by weight, based on the total weight of 100 parts by weight of the electrode.

[0101] If the binder content in the electrode slurry is less than the lower limit based on the total weight of 100 parts by weight of the slurry, the mechanical properties of the electrode may be weakened, potentially leading to detachment of the electrode's active layer from the current collector or cracks in the electrode's active layer. Conversely, exceeding the upper limit due to the binder content may lead to a reduction in energy density and an increase in electrochemical resistance.

[0102] The electrode may have the binder for secondary battery electrodes and the electrode active material applied to the current collector.

[0103] The current collector may include one or more elements selected from the group consisting of aluminum (Al), copper (Cu), nickel (Ni), and carbon.

[0104] The electrode active material may be a conventional positive electrode active material. Non-limiting examples include lithium cobalt oxide (LiCoO2), lithium manganese oxide with spinel structure (LiMn2O4), lithium manganese oxide (LiMnO2), lithium nickel oxide (LiNiO2), lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), lithium iron pyrophosphate (Li2FeP2O7), lithium niobium oxide (LiNbO2), lithium iron oxide (LiFeO2), lithium magnesium oxide (LiMgO2), lithium copper oxide (LiCuO2), lithium zinc oxide (LiZnO2), lithium molybdenum oxide (LiMoO2), lithium tantalum oxide (LiTaO2), lithium tungsten oxide (LiWO2), layered lithium manganese nickel cobalt oxide (xLi2MnO3 (1-x)LiMn1-y-zNiyCozO2), lithium nickel cobalt aluminum oxide (LiNi 0,8 Co 0,15 Al 0,05 O2), nickel manganese oxide (LiNi 0,5 Mn 1,5 O4) and various lithium nickel cobalt manganese oxides (e.g. LiNi 0,33 C0 0,33 Mn 0,33 O2, LiNi 0,4 Co 0,2Mn 0,4 O2, LiNi 0,5 Co 0,2 Mn 0,3 O2, LiNi 0,6 Co 0,2 Mn 0,2 O2, LiNi 0,7 Co 0,15 Mn 0,15 O2, LiNi 0,8 Co 0,1 Mn 0,1 O2), but the invention is not limited to these examples.

[0105] In particular, in the electrode of the present invention, the binder for secondary battery electrodes and the electrode active material can be mixed together. This approach differs from simply coating a metal electrode or the electrode active material with the binder. Through electrostatic interaction with the liquid electrolyte impregnated into the porous structure of the electrode, this method can increase the mobility of cations while simultaneously fixing the corresponding anions.

[0106] The electrode may further contain a conductive material.

[0107] The conductive material is not particularly limited as long as it is generally used in the art, but may be a carbon-based conductive material, as a non-limiting example. The carbon-based conductive material may include a dot-shaped carbon-based conductive material, a linear carbon-based conductive material, a plate-shaped carbon-based conductive material, or a mixture thereof. Examples of the dot-shaped carbon-based conductive material include acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon black, and the like. Examples of the linear carbon-based conductive material may include carbon nanotubes, conductive carbon fibers, and the like. Examples of the plate-shaped carbon-based conductive material include graphene (including GRO).

[0108] If the electrode contains a conductive material, the cationic monomer interacts with the electrode active material and the conductive material in the electrode slurry. This interaction increases the repulsive forces between the electrode materials due to the high surface charge, thereby improving the distribution of the materials in the electrode slurry.

[0109] The conductive material may be contained in an amount of 1 to 7 parts by weight based on the total weight of 100 parts by weight of the electrode, and preferably in an amount of 2 to 5 parts by weight.

[0110] If the amount of conductive material is less than the lower limit based on the total weight of 100 parts of the electrode, the electrical conductivity of the electrode may be reduced. Conversely, if the amount exceeds the upper limit, the energy density may be reduced.

[0111] Another aspect of the present invention is the provision of a secondary battery comprising the electrode. The battery contains a cationic semi-interpenetrating network (semi-IPN) polymer within the electrode, which interacts with the liquid electrolyte impregnated into the porous structure. This interaction increases the mobility of cations while fixing the corresponding anions, thereby increasing the ionic conductivity within the electrode and contributing to improved performance and charging characteristics of the electrode.

[0112] The secondary battery may include one or more elements selected from the group consisting of lithium (Li), sodium (Na), zinc (Zn) and aluminum (Al).

[0113] Preferably, the secondary battery may be a lithium secondary battery.

[0114] Another aspect of the present invention is a device that includes the battery. The device can be selected from one of the following: a communication device, a transportation device, or an energy storage device.

[0115] Another aspect of the present invention provides a method for producing a secondary battery electrode, including: (a) a step of preparing an electrode slurry by adding a binder and an electrode active material to a solvent; and (b) a step of obtaining the electrode by coating the electrode slurry. The binder used in the method includes a cationic monomer, a crosslinkable multifunctional monomer, and a linear polymer. (a) A step of preparing an electrode slurry by adding a binder and an electrode active material to a solvent

[0116] Step (a) is a step in which an electrode slurry is prepared by adding a binder and an electrode active material to a solvent.

[0117] The solvent may be one or more selected from the group consisting of dimethylformamide (DMF), methanol (MeOH), ethanol, propanol, isopropyl alcohol (IPA), tert-butyl alcohol (TBA), n-butane, methoxyethanol, ethoxyethanol, dimethylacetamide, dimethylformamide, and N-methyl-2-pyrrolidone (NMP). Preferably, the solvent is N-methyl-2-pyrrolidone (NMP).

[0118] The binder may include a cationic monomer, a crosslinkable multifunctional monomer, and a linear polymer.

[0119] The cationic monomer refers to a monomer that has a cationic group.

[0120] The cationic group can be selected from one or more of the following: imidazolium, pyridinium, phosphonium, sulfonium, piperidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium, and morpholinium. Preferably, the cationic group is imidazolium, and more preferably, it is 1-vinyl-3-allylimidazolium.

[0121] The cationic monomer may contain a counterion selected from one or more of the following: BF4 - , B(CN)4 - , CH3BF3 - , CH2CHBF3 - , CF3BF3 - , C2F5BF3 - , n-C3F7BF3 - , n-C4F9BF3 - , PF6-, CF3CO2 - , CF3S03 - , N(SO2CF3)2 - (TFSI - ), N(COCF3)(SO2CF3) - , N(SO2F)2 - , N(CN)2 - , C(CN)3 - , SCN - , and SeCN - . Preferably the counterion is N(SO2CF3)2 - (TFSI - ).

[0122] The crosslinkable multifunctional monomer refers to a monomer that has at least two polymerizable functional groups.

[0123] The crosslinkable multifunctional monomer may include one or more selected from the group consisting of acrylic-based, conjugated diene-based, alkene-based, diol-based, fatty acid-based, amino acid-based, hydroxy acid-based, ester-based, lactone-based, carbonate-based, cyclic ether-based, lactam-based monomers and their derivatives.

[0124] The polymerizable functional groups may include one or more selected from the group consisting of acrylate groups, methacrylate groups, vinyl groups, and thiol groups. Preferably, the polymerizable functional group is an acrylate group.

[0125] Specific examples of crosslinkable multifunctional monomers with two polymerizable functional groups include ethylene glycol diacrylate (EGDMA), triethylene glycol diacrylate (TEGDA), polyethylene glycol diacrylate (PEGDA), and 1,6-hexanediol diacrylate (HDDA).

[0126] Specific examples of the crosslinkable monomer including a polyfunctional group having three polymerizable functional groups may include ethoxylated trimethylolpropane triacrylate (ETPTA), trimethylolpropane propoxylate triacrylate (TPPTA), pentaerythritol triacrylate (PETA), and trimethylolpropane triacrylate (TMPTA).

[0127] The network polymer can be obtained by polymerizing the cationic monomer and the crosslinking multifunctional monomer in a weight ratio of 0.8 to 7:1, preferably 1.2 to 5:1, more preferably 1.5 to 3:1, and most preferably 1.7 to 2.5:1.

[0128] The network polymer can be represented by the following chemical formula 1:

[0129] (In Chemical Formula 1, \(n\) and \(m\) represent the degree of polymerization of each monomer unit, where \(n\) is an integer in the range of 1 to 400 and \(m\) is an integer in the range of 1 to 200. Preferably, the ratio \(n:m\) is between 1:1 and 2:1.)

[0130] The linear polymer may contain a fluorine-containing polymer.

[0131] The fluorine-containing polymer may be selected from one or more of the following: polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), copolymers of polyvinylidene fluoride with hexafluoropropylene (PVdF-HFP), and copolymers of polyvinylidene fluoride with tetrafluoroethylene (PVdF-TFE).

[0132] The linear polymer may be contained in an amount of 45 to 100 parts by weight, preferably 50 to 90 parts by weight, and more preferably 55 to 70 parts by weight, based on 100 parts by weight of the crosslinked polymer.

[0133] The electrode active material may be any conventional cathode active material. Non-limiting examples include lithium cobalt oxide (LiCoO2), spinel-type lithium manganese oxide (LiMn2O4), lithium manganese oxide (LiMnO2), lithium nickel oxide (LiNiO2), lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), lithium iron pyrophosphate (Li2FeP2O7), lithium niobium oxide (LiNbO2), lithium iron oxide (LiFeO2), lithium magnesium oxide (LiMgO2), lithium copper oxide (LiCuO2), lithium zinc oxide (LiZnO2), lithium molybdenum oxide (LiMoO2), lithium tantalum oxide (LiTaO2), lithium tungsten oxide (LiWO2), layered lithium manganese nickel cobalt oxide (xLi2MnO3 (1-x)LiMn1-y-zNiyCozO2), lithium nickel cobalt aluminum oxide (LiNi0,8 Co 0,15 Al 0,05 O2), nickel manganese oxide (LiNi 0,5 Mn 1,5 O4) and lithium nickel cobalt manganese oxides (e.g. LiNi 0,33 C0 0,33 Mn 0,33 O2, LiNi 0,4 Co 0,2 Mn 0,4 O2, LiNi 0,5 Co 0,2 Mn 0,3 O2, LiNi 0,6 Co 0,2 Mn 0,2 O2, LiNi 0,7 Co 0,15 Mn 0,15 O2, LiNi 0,8 Co 0,1 Mn 0,1 O2). However, these examples are not limiting.

[0134] The electrode may also contain a conductive material.

[0135] The conductive material is not particularly limited as long as it is widely used in the field. Non-limiting examples include carbon-based conductive materials. These carbon-based conductive materials can be in the form of spherical carbon-based conductive materials, linear carbon-based conductive materials, planar carbon-based conductive materials, or mixtures thereof.

[0136] Examples of spherical carbon-based conductive materials include acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon black. Examples of linear carbon-based conductive materials include carbon nanotubes and conductive carbon fibers. Examples of planar carbon-based conductive materials include graphene (including GRO).

[0137] The electrode slurry may also contain a polymerization initiator that causes the cationic monomer and the multifunctional crosslinking monomer to polymerize and form a crosslinked polymer.

[0138] The initiator can be a peroxide-based initiator, including but not limited to benzoyl peroxide (BPO), dicumyl peroxide, dibutyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxy)-3,3,5-trimethylcyclohexane, 3,1,3-bis(t-butylperoxyisopropyl)benzene, n-butyl 4,4-bis(t-butylperoxy)valerate, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, and t-butyl perbenzoate lauryl peroxide. (b) The step of applying the electrode slurry to obtain an electrode

[0139] Step (b) is the step of applying the electrode slurry to obtain an electrode.

[0140] The application may be carried out using one or more methods selected from the group consisting of doctor blade coating, roller coating, bar coating, slot die coating, comma coating, brush coating, gravure coating, microgravure coating, dip coating, flow coating, spin coating and spray coating.

[0141] The application in step (b) can be carried out by applying the electrode slurry to a current collector.

[0142] The current collector may contain one or more materials selected from the group consisting of aluminum (Al), copper (Cu), nickel (Ni) and carbon.

[0143] After step (b), the process may further comprise the step of heat treating the applied electrode slurry.

[0144] The heat treatment can be carried out at a temperature in the range of 25 to 120 °C, preferably 80 to 120 °C.

[0145] If the heat treatment temperature is below the lower limit, the cross-linked polymer may not polymerize sufficiently. Conversely, if the temperature is above the upper limit, rapid evaporation of the electrode slurry may lead to delamination of the electrode layer.

[0146] During heat treatment, the cationic monomer and the multifunctional crosslinking monomer can polymerize to form a crosslinked polymer. This results in the formation of a cationic semi-interpenetrating network polymer (semi-IPN), which has a structure in which the crosslinked polymer and the linear polymer are intermixed.

[0147] The following examples serve to further illustrate the invention in detail. However, it should be noted that the scope and content of the invention should not be construed as limited or reduced by these examples. Example 1 Cationic semi-interpenetrating polymer network (c-IPN, TMPTA) Synthesis of 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI)

[0148] 1-Vinyl-3-allylimidazolium bromide (VAI-Br) was synthesized as an intermediate of VAI-TFSI. 10.0 mmol of 1-vinylimidazole (Sigma-Aldrich) was mixed with 50 mL of acetonitrile (Sigma-Aldrich) and 12.0 mmol of allyl bromide (Sigma-Aldrich). The acetonitrile was then removed using a rotary evaporator, and the resulting crude product was purified by decantation using 20 mL of ethyl acetate and 20 mL of diethyl ether, respectively, to synthesize 1-vinyl-3-allylimidazolium bromide (VAI-Br).

[0149] Of the synthesized 1-vinyl-3-allylimidazolium bromide (VAI-Br), 7.5 mmol was dissolved in 50 mL of deionized water, and then 7.5 mmol of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) was added to the solution. The resulting mixture was extracted with 100 mL of dichloromethane. To remove any remaining organic impurities, the solution was further extracted with another 50 mL of deionized water. The resulting dichloromethane layer was purified by column chromatography with neutral alumina, and the dichloromethane was removed with a rotary evaporator to obtain VAI-TFSI. The obtained VAI-TFSI was then dried overnight in a vacuum oven. The chemical structure of VAI-TFSI was determined using the 1 H-NMR spectroscopy confirmed. Manufacturing the c-IPN electrode

[0150] A positive electrode slurry was prepared by dissolving LiNi 0,8 Co 0,1 Mn 0,1O2 (NCM811, LG Energy Solution) and carbon black (Super C65) in N-methyl-2-pyrrolidone (NMP, Aldrich) with a composition ratio of 92 / 3 / 5 (w / w / w). The binder used consisted of PVDF, a crosslinking agent trimethylolpropane triacrylate (TMPTA), and the previously prepared VAI-TFSI with a weight ratio of 3 (60):0.7 (13):1.3 (27). Benzoyl peroxide (BPO, 1 wt%) was used as the thermal initiator. The molar ratio of VAI-TFSI to TMPTA was 1.6:1.

[0151] In the final electrode, a cationic semi-interpenetrating network (semi-IPN) polymer was formed, which consists of a network polymer generated by the polymerization of VAI-TFSI and TMPTA blended with PVDF.

[0152] Next, the aforementioned electrode slurry was poured onto the Al current collector. After pouring, the electrode slurry was dried at 100 °C for one hour, roll-pressed at 90 °C, and then vacuum-dried at 120 °C for 12 hours before cell assembly. The electrode density of the final electrode was set to 2.8 g / cm for fair comparison. 3 In the following experimental examples, the above-mentioned electrode was used as the cathode. Example 2 TPPTA

[0153] The electrode was prepared in the same manner as in Example 1, except that trimethylolpropane propoxylate triacrylate (TPPTA) was used as the crosslinking agent instead of trimethylolpropane triacrylate (TMPTA). Example 3 ETPTA

[0154] The electrode was prepared in the same manner as in Example 1, except that ethoxylated trimethylolpropane triacrylate (ETPTA) was used as the crosslinking agent instead of trimethylolpropane triacrylate (TMPTA). Comparative example 1. n-IPN

[0155] The electrode slurry and the electrode were prepared in the same manner as in Example 1, except that polyvinylidene fluoride (PVDF, Solvay) was used as a binder and trimethylolpropane triacrylate (TMPTA) was used as a crosslinking agent in a weight ratio of 3:2. Comparative example 2. PVDF

[0156] The electrode slurry and the electrode were prepared in the same manner as in Example 1, except that only polyvinylidene fluoride (PVDF, Solvay) was used as the binder. Experimental example. Determination of test conditions. Structural properties.

[0157] The electrochemical stability window of the cross-linked TMPTA and VAI-TFSI / TMPTA binders was investigated using linear sweep voltammetry (LSV) performed with the working electrode (stainless steel) and the reference / counter electrode (Li metal). The LSV measurements were performed at a scan rate of 1.0 mVs. -1 carried out.

[0158] The surface tension at the interface between the electrode slurry and the gas was measured using a surface analyzer (Phoenix 300, SEO) using the pendant drop method. To ensure the reliability of the zeta potential measurement data (Zetasizer Nano ZS, Malvern), a model suspension was prepared at a diluted concentration (10 ppm) using NMP as the solvent. The model suspension consisted of a mixture of conductive carbon additive and binder in a ratio of 3:5 (w / w) in NMP, without the addition of NCM811 powder. This composition ratio of the model suspension was determined taking into account the composition ratio of the cathode (NCM811 / carbon black additive / binder = 92 / 3 / 5 (w / w / w)).

[0159] The surface morphology and height deviation of the uncompressed electrode were characterized using a confocal laser scanning microscope (FV1000, Carl Zeiss). Height deviation was defined as the difference between the observed electrode height and the average height.

[0160] The thermal cross-linking reaction of the c-IPN and n-IPN electrodes was measured using a Fourier transform infrared spectrometer (Alpha Platinum ATR, Bruker) with a spectral resolution of 4 cm -1 investigated. The glass transition temperature (T g ) of the binder was measured using a differential scanning calorimeter (Q2000, DuPont) with a heating rate of 20 °C min -1 appreciated.

[0161] The tensile test of the binder film was carried out using a universal testing machine (DA-01, Petrol LAB) at a strain rate of 0.5 mm min -1The bond strength between the electrode and the Al current collector was measured using the same universal testing machine (DA-01, Petrol LAB) at a peel speed of 160 mm / min. To measure electrolyte swelling, the electrode was immersed in a liquid electrolyte (1 M LiPF6 in ethylene carbonate (EC) / diethyl carbonate (DEC) (1 / 1 (v / v))) at 25 °C, and the weight change was recorded as a function of immersion time.

[0162] The cross-sectional morphology of the electrode was characterized using a field emission scanning electron microscope (S-4800, Hitachi) combined with an energy-dispersive X-ray spectrometer (JSM 6400, JEOL). Sample preparation was performed using an ion beam etching system (IM4000, Hitachi). The internal structure of the pouch cell was characterized using X-ray microtomography (Xradia 520 Versa, Carl Zeiss Inc.).

[0163] During tomography, 993 projection images were acquired at a 4x optical magnification. To analyze the microstructure of the cycled NCM811 particles, cross-sectional samples were thinned using a focused ion beam (Helios Nano Lab 450, FEI). Structural and chemical analysis of the thinned samples was performed using a high-resolution transmission electron microscope (HR-TEM, ARM300, JEOL). Electrochemical and physicochemical properties

[0164] The electronic conductivity of the electrode was measured using a four-point probe station (CMT-SR1000N, Advanced Instrument Tech). Analysis of the symmetric cell (electrode||electrode) by electrochemical impedance spectroscopy (EIS) was performed in the fully lithiated state using a potentiostat / galvanostat (VSP classic, BioLogic) over a frequency range of 10 -2 up to 10 6Hz with an applied amplitude of 10 mV.

[0165] The electrochemical performance of the electrode was characterized using 2032 button cells and pouch cells with the following configuration: NCM811 cathode || polyethylene (PE) separator (thickness = 16 µm) || Li-metal anode (thickness = 100 µm) and a liquid electrolyte consisting of 1 M LiPF6 in EC / DEC = 1 / 1 (v / v) containing 10 wt% fluoroethylene carbonate (FEC) and 1 wt% vinylene carbonate (VC). Unless otherwise stated, the electrolyte mass to cell capacity (E / C) ratio was 2.5 gA / h. A double-stacked pouch cell was constructed using a c-IPN cathode (C / A 18 mAh cm -2 ) || Li-metal anode (C / A 20 mAh cm -2 ) and the film was packaged in a dry room with a dew point of -50 °C.

[0166] The electrochemical performance of the pouch cell was estimated at 25 °C under a fixed pressure of 300 kPa. The specific energy and energy density of the button cell were estimated based on the weight / volume of the cathode (including the Al current collector), the anode (including the Cu current collector), the separator, and the electrolyte within the cell. Meanwhile, the specific energy and energy density of the pouch cell were estimated based on the experimentally measured weight / volume of the entire cell, including the pouch packaging film.

[0167] The detailed calculations for these energy densities are shown in Tables 1 and 2. The analysis using the galvanostatic intermittent titration technique (GITT) was carried out at a current density of 0.1 C (= 1.35 mA cm -2) with a rest period of 30 minutes between each pulse. The electrochemical reaction kinetics of the electrode were investigated using cyclic voltammetry at a scan rate of 0.1 mV / s. The electrochemical performance of the cells was tested under various charge and discharge conditions using a cycle tester (PEBC050.1, PNESolution).

[0168] The degree of delithiation in the electrode along the thickness direction was confirmed using a Raman spectrometer (NRS-3100, JASCO). The oxidation state of the transition metal ions in the NCM811 particles was estimated by estimating the intensity ratio of the E modes. g (Bending mode along the metal-oxygen-metal axis a / b) and A 1g(stretching mode along the c-axis of the metal-oxygen complex). The structural evolution and electrostatic interactions between the electrode and the anions (or solvents) were monitored using Fourier transform infrared spectroscopy (FTIR, Alpha Platinum ATR, Bruker).

[0169] The local environment of Li + within the electrode was determined using the 7 Li magic angle spinning (mAS) nuclear magnetic resonance (NMR) spectroscopy (600 MHz FTNMR, VNMRS 600, Agilent) equipped with a 1.6 mm HXY Fast mAS T3 probe and a spin rate of 20 kHz.

[0170] The chemical shifts of 7Li were referenced to an external standard of 1.0 M aqueous LiCl solution at 0 ppm. For post-analysis, the cell was disassembled after 100 cycles in the discharged state, and the residual salts were removed by purging with solvent (DMC) in an argon-filled glove box. Samples for post-analysis were transported in sealed bags filled with inert gas.

[0171] The chemical changes on the surface of the cycled NCM811 were analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS 5, ION TOF) equipped with a Bi 2+ gun (25 keV, 1 pA) and X-ray photoelectron spectroscopy (XPS) using focused monochromatic Al Kα radiation (ESCALAB 250XI, ThermoFisher). Molecular dynamics simulation

[0172] All molecular dynamics (MD) simulations were performed using mAterials Studio 2019 R2 (BIOVIA mAterials Studio) software. The COMPASSII force field was used to describe the interactions between LiPF6, EC, DEC, VAI-TFSI, and TMTPA monomers. Van der Waals interactions were calculated using the atom-based cutoff method with a cutoff distance of 12.5 Å, while electrostatic interactions were handled using the Ewald summation method.

[0173] Temperature and pressure were controlled using the Nose-Hoover-Langevin (NHL) thermostat and the Berendsen barostat, with the time coupling constants set to 1 ps and 0.1 ps, respectively. To determine the solvation properties of Li +To investigate the potential for ligand binding near the c-IPN and n-IPN binder units, modeling of the overall polymer system was performed. Ten monomers were prepared and equilibrated to describe the polymer binder chains. A detailed description of each model system is summarized in Table 7. The initial model systems were relaxed by geometry optimization using the steepest descent method.

[0174] The convergence criteria for the optimization were set to a maximum energy change of 0.001 kcal / mol and a maximum force of 0.5 kcal / mol·Å. After optimization, a standard ensemble simulation (i.e., NVT) was performed at 298 K for 500 ps. In the second phase, an isothermal-isobaric ensemble simulation (i.e., NPT) was performed at 298 K and 1 bar for 500 ps to achieve equilibrium. After equilibrating the overall structure of the binder system, the cell was expanded and each system was solvated with 1 M LiPF6 in EC / DEC = 1 / 1 (v / v) to describe the binder-electrolyte interface.

[0175] The equilibration of the solvated binder system was carried out in three steps. First, the same geometry optimization was performed as for the equilibration of the overall polymer system. Second, an NVT simulation was performed at 298 K for 500 ps. Finally, an NPT simulation was performed at 298 K and 1 atm for 4 ns. For the solvation analysis, the radial distribution function (RDF, g αβ (r)) is used, which is described by the following equations (Equation 1 and Equation 2). xαxβρgαβ(r)=1N(∑i=1Na∑j=1Nβδ(r−ri−rj))

[0176] In equation 1, x i the mole fraction of the chemical species i, N i is the number of atoms (or molecules) of chemical species i or j, N is the total number of atoms, and ρ is the total particle density. The modified equation yields the coordination number (n αβ(r)), which is derived from the equation. nαβ(r)=4πρβ∫r0r1r2gαβ(r)dr

[0177] In equation 2, p β represents the uniform particle density of the atom β, and the integration region between r0 and r1 corresponds to the first solvation shell. All analyses were performed for the last 1 ns of the NPT trajectory. Density functional theory calculation

[0178] Density functional theory (DFT) calculations were performed using the program DMol3 to determine the HOMO (Highest Occupied Molecular Orbital) energy levels of the Li +To investigate the solvation structure at the binder / electrolyte interface, the generalized gradient approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional was used, and the core electrons were treated with relativistic effects in all-electron calculations. The van der Waals (vdW) energy correction was applied according to the Grimme method to account for vdW interactions.

[0179] Spin polarization was included in all calculations. The molecular orbitals were augmented using the Double Numerical Plus Polarization (DNP) 4.4 basis set, with a global orbital cutoff set to 5.1 Å. The convergence criterion for consistent calculations was set to 1×10 -6The solvation shell of the lithium atom was described using the COSMO method (Conductor-like Screening Model), applying a dielectric constant of ε = 13.637. The dielectric constant (ε) of the solvation shell was calculated using Equation 3, which takes into account the dielectric constant of the heterogeneous electrolyte mixture. ε=[(ε21 / 3−ε11 / 3)v2+ε11 / 3]3

[0180] In equation 3, ε i is the dielectric constant of each electrolyte i (i.e. 89.78 for ethylene carbonate and 2.81 for diethyl carbonate), and v2 denotes the volume fraction of the respective electrolyte. Experimental Example 1. The realization of a lithium metal full cell with high energy density was confirmed.Wound cell

[0181] Using the cathode (c-IPN) prepared in Example 1 with different C / A ratios and a 100 µm Li-metal anode (corresponding to 20 mAh cm -2) cells were assembled with an electrolyte mass / cell capacity (E / C) ratio of 2.5 gA / h. The nominal cell voltage was estimated by integrating the discharge profile divided by the discharge capacity. The specific energy and energy density of the button cells with the c-IPN cathode were calculated according to equations 4 and 5 without packaging materials. The results are shown in Fig. 2A and Tables 1 and 2. Specific energy (W h kg−1) = Energy Cell mass = Nominal voltage × cMCathode + MAnode + MSeparator + MElectrolyte

[0182] (In equation 4, M Kathode , M Anode , M Separator and M Elektrolyt correspondingly for the masses of the cathode (including the Al current collector), the anode (including the Cu current collector), the separator and the injected electrolyte, while C denotes the discharge capacity.) Energy density (Wh L−1) = Energy Cell volume = Nominal voltage × C / AT cathode + T anode + T separator

[0183] (In equation 5, T Kathode , T Anode and T Seperator correspondingly for the thickness of the cathode (including the 16 µm thick Al foil), the anode (including the 9 µm thick Cu foil) and the separator.) [Table 1] C / A (mAh cm -2 ) C (mAh) M Kathode (mg) M Anode (mg) M Separator (mg) M Elektrolyt (mg) M Gesamt (mg) Specific energy (Wh kg -1 ) 2,41 2,72 20,29 15,09 3.02 6,80 44,97 228 5,38 6,07 37,29 15,09 3.02 15,18 70,36 326 7,14 8,08 47,60 15,09 3.02 20,19 85,67 356 9,25 10,45 60,30 15,09 3.02 26,14 104,32 378 11,98 13,54 76,97 15,09 3.02 33,86 128,71 397 14,59 16,49 93,30 15,09 3.02 41,22 152,41 409 16,24 18,35 101,41 15,09 3.02 45,88 165,17 420 17,99 20,33 111,30 15,09 3.02 50,82 180,00 427 20,18 22,70 124,50 15,09 3,02 56,75 199,13 431 [Table 2] C / A (mAh cm -2 ) T Kathode (µm) T Anode (µm) T Separator (µm) Energy density (Wh L -1 ) 2,41 61 109 16 490 5,38 114 109 16 852 7,14 147 109 16 993 9,25 187 109 16 1122 11,98 240 109 16 1242 14,59 291 109 16 1327 16,24 318 109 16 1386 17,99 348 109 16 1438 20,18 390 109 16 1482

[0184] Fig. Figure 2A is a diagram showing the specific energy and specific capacity of the active material (C sp ) of the NCM811 battery as a function of the areal mass loading (M / A) of the cathode electrode prepared in Example 1 (c-IPN) of the present invention. The values ​​given exclude packaging materials.

[0185] As in Fig.As shown in Figure 2A and Tables 1 and 2, the specific energy of the cell increased with the M / A and reached at a M / A of 86 mg cm -2 a saturation level of about 427 Wh kg Zelle -1 (without packaging materials). In addition, the specific capacity (C sp ) of NCM811 (~210 mAh / g NCM811) was maintained over a wide range of M / A values, indicating that NCM811 can be effectively used even in thick c-IPN cathodes. Consequently, the cathode of Example 1 (c-IPN) delivered a C / A of 20 mAh cm -2 , which is about five times higher than that of a commercial lithium-ion battery (LIB) based on neutral, linear polyvinylidene fluoride (PVDF) (~4 mAh cm -2 ).

[0186] Meanwhile, a comparison of C / A, Csp, Csp / theoretical Csp ratio, and specific energy (without packaging materials) between the electrode of the present invention and previously described high C / A ratio electrodes (mainly button cell based) is provided in the following Table 3. [Table 3] reference Cell type C / A (mAh cm -2 ) C sp (mAh g-1) Use (C sp / theor. C sp = % Specific energy (Wh kg -1 ) This study Double stacked pouch 20 210 (NCM811) 100 431 1 Simply stacked pouch 9 112 (NCM111) 72 206 2 Simply stacked pouch 6 158 (NCM622) 93 246 3 Simply stacked pouch 12 203 (NCM811) 97 404 4 Button 8 128 (LCO) 88 - 5 Button 21 144 (LFP) 85 - 6 Button 2 150 (LFP) 88 - 7 Button 14 133 (LFP) 78 - 8 Button 7 140 (LFP) 82 - 9 Button 9 130 (LMFP) 86 - 10 Button 14 142 (LCO) 97 - 11 Button 22 106 (LFP) 73 219 12 Button 7 126 (LFP) 74 - 12 Button 23 158 (LFP) 93 - 13 Button 28 132 (LCO) 91 - 14 Button 10 112 (NCM111) 72 205 15 Button 29 185 (NCM811) 95 401 16 Button 13 162 (OLO) 65 - 17 Button 16 152 (LFP) 89 - 18 Button 9 146 (LFP) 85 -

[0187] As shown in Table 3, it can be confirmed that the electrode prepared in Example 1 (c-IPN) has superior performance compared to commonly reported electrodes. Double laminated pouch-type full cell

[0188] Fig. Figure 2B is a micrograph of the double stacked pouch cell using the electrode cathode (C / A = 18 mAh cm -2 ) prepared in Example 1 (c-IPN).

[0189] Fig.3 is a photograph of the double stacked pouch type full cell showing the electrode cathode (C / A = 18 mAh cm -2 ) prepared in Example 1 (c-IPN) of the present invention.

[0190] Since button cells are not sufficient to demonstrate the scalability of the electrode, as in the Fig. 2B and Fig. As shown in Figure 3, a double stacked pouch-type full cell was prepared using the electrode cathode prepared in Example 1 (c-IPN) (C / A = 18 mAh cm -2 ). This cathode was combined with a Li-metal anode (20 mAh cm -2 , cathode-anode capacity ratio (N / P) of 1.1) under a limited amount of electrolyte (with an electrolyte mass / cell capacity (E / C) ratio of 2.5 gA / h for the carbonate-based liquid electrolyte). The double-stacked pouch cell had an area of ​​34 × 34 mm 2The performance and characteristics of this cell have been estimated and the results are presented in the Fig. 2C to D, 4 and 5.

[0191] Fig. Figure 2C shows an X-ray microtomography image illustrating the cross-sectional structure of the double-stacked pouch cell containing the electrode cathode (C / A = 18 mAh cm) prepared in Example 1 (c-IPN). -2 ) used.

[0192] As in Fig. As shown in Figure 2C, it was confirmed that the electrode cathode prepared in Example 1 (c-IPN) with a thickness (350 µm) is present in the double-stacked pouch cell.

[0193] The Fig. 4A and Fig. 4B shows the charge / discharge profiles at constant current (A) and the corresponding dQ / dV diagrams (B) of the double-stacked pouch cell at the 2nd, 40th, and 50th cycles using the electrode cathode prepared in Example 1 (c-IPN). Fig. 4A and Fig.4B the current density was 0.9 mA cm -2 / 1.8 mA cm -2 and the voltage range was between 3.0 and 4.4 V. The cycled cathode was reassembled in the 50th cycle with a new lithium metal anode, a separator, and a liquid electrolyte.

[0194] As in the Fig. 4A and Fig. As shown in Figure 4B, the fabricated cell produced a specific capacity (C sp ) of 210 mAh g NCM811 -1 , which suggests that the theoretical C sp was almost completely used by NCM811.

[0195] Fig. 5 shows the comparison results of specific energy and energy density between the high energy density pouch cell using the electrode cathode prepared in Example 1 (c-IPN) of the present invention and the previously described high energy density pouch cells.

[0196] The Fig.The values ​​presented in Figure 5 are the estimated specific energy and energy density based on the total mass and volume (including packaging materials) of the pouch cell. The cell parameters used for these estimates are listed in Table 4 below.

[0197] Table 4 provides detailed information for calculating the specific energy and energy density for the double-stacked pouch-type full cell (including packaging materials). The cathode and anode areas in the cell were 34 × 34 mm, respectively. 2 and 36 × 36 mm 2 . [Table 4] Cell components Mass (mg) M / A (mg cm -2 ) C / A (mAh cm -2 ) Thickness (µm) Cathode #1 1143 98,87 18,05 348 Cathode #2 1139 98,52 17,99 347 anode 266 20,55 20 (per single page) 209 separator 17 - - 32 electrolyte 1042 - - - Pouch packaging 230 - - 117 Pouch parameters *Stack In total Mass (mg) 3607 4191 Thickness (µm) 936 1166 Capacity (mAh) 416 Energy (mWh) 1554 Specific energy (Wh kg -1 ) 437 376 Energy density (WhL -1 ) 1457 1043 *Stack corresponds to the pouch cell core without the pouch cell packaging materials.

[0198] As in Fig. As shown in Figure 5 and Table 4, the specific energy and energy density of the double-stacked pouch cell using the cathode (c-IPN) prepared in Example 1 reached higher values ​​than previously reported high-energy-density pouch cells, namely 376 Wh kgZelle -1 and 1043 Wh L Zelle -1 (including packaging materials). This suggests that the present invention could further improve the energy density of the cell by introducing a multi-cell stack configuration, thereby reducing the weight / volume contribution of packaging materials in the overall cell.

[0199] Fig. Figure 2D shows the cycle performance of the double stacked pouch cell using the electrode cathode (C / A = 18 mAh cm -2 ) prepared in Example 1 (c-IPN). Cycling was carried out at 25 °C with a charge / discharge current density of 0.9 mA cm -2 / 1.8 mA cm -2 and within a voltage range of 3.0-4.4 V.

[0200] As in the Fig. 2D, Fig. 4A and Fig. 4B, demonstrated the electrode cathode prepared in Example 1 (c-IPN) (C / A = 18 mAh cm-2 ), a double-stacked pouch cell demonstrated stable cycling performance even without the use of non-traditional electrolytes specifically designed for Li-metal anodes. Notably, after replacing the cycled Li-metal anode, liquid electrolyte, and separator with new parts, the cell almost completely recovered its original C / A, confirming that the c-IPN cathode was not the primary cause of the cycling deterioration. Main causes of cycle degradation in Li-metal full cells

[0201] To identify the main reasons for the decline in cycles in Fig. To determine the performance of the Li-metal full cell shown in Figure 2D, three model cells were prepared as follows. The charge / discharge current rates of 0.05 C / 0.1 C (= 0.9 mA cm-2 / 1.8 mA cm -2) and the constant current charge / discharge profiles cycled in the voltage range of 3.0-4.4 V for the reassembled pouch cells are shown in the Fig. 6A to 6C.

[0202] Model cell No. 1: Cycled cathode with new liquid electrolyte || New Li-metal anode)

[0203] Model cell No. 2: (Cycled cathode || New Li-metal anode with cycled liquid electrolyte)

[0204] Model cell No. 3: Cycled cathode with new liquid electrolyte || Cycled Li-metal anode).

[0205] The Fig.6A to 6C show the constant current charge / discharge profiles of (a) Cell No. 1 (cycled cathode || new Li-metal anode with new liquid electrolyte), (b) Cell No. 2 (cycled cathode | new Li-metal anode with cycled liquid electrolyte), and (c) Cell No. 3 (cycled cathode with new liquid electrolyte | cycled Li-metal anode) in Experimental Example 1 of the present invention.

[0206] As in the Fig. As shown in Figures 6A to 6C, model cells No. 1 and No. 2 returned to their original voltage profiles with a high C / A value (∼18 mAh cm -2). However, model cell No. 3 did not return to its original voltage profile even with the new liquid electrolyte and showed a rapid decrease in capacity during cycling. This suggests that replacing the cycled liquid electrolyte with a new one while leaving the cycled Li-metal anode unchanged failed to restore the original voltage profile and led to rapid capacity deterioration upon continued cycling. On the other hand, replacing the cycled Li-metal anode with a new one allowed the cell to return to a normal and stable voltage profile. This observation confirms that the cycled Li-metal anode is the main reason for cycling deterioration in full cells using a high C / A ratio cathode. Experimental Example 2. Control of electrostatic phenomena in the dispersed state of the c-IPN cathode

[0207] Fig. 7 shows the 1 H nuclear magnetic resonance (NMR) spectrum and chemical structure of 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI) synthesized in Example 1 of the present invention.

[0208] Fig. Figure 8 illustrates the electrochemical stability window measured by linear sweep voltammetry (LSV) for TMPTA / VAI-TFSI and trimethylolpropane triacrylate (TMPTA) prepared in Example 1 of the present invention.

[0209] The Fig. 9A and Fig. 9B show (A) the discharge rate performance and (B) the critical crack thickness (CCT) and critical delamination thickness (CDT) of the cathode (M / A = 65 mg cm -2 ) using TMPTA / VAI-TFSI with varying composition ratios as prepared in Example 1 of the present invention. In Fig. 9, CCT refers to the critical electrode thickness at which cracks occur during electrode drying, while CDT refers to the critical electrode thickness at which the electrode layer peels off from the Al current collector during roll pressing.

[0210] As in the Fig. 9A and Fig. As shown in Figure 9B, the electrode discharge rate tended to increase with increasing VAI-TFSI content. However, due to the weak bonding strength of VAI-TFSI, the electrode adhesion decreased slightly. Consequently, the optimal composition ratio of TMPTA / VAI-TFSI within the samples was found to be 1 / 2 (w / w). Experimental Example 3: Control of electrostatic phenomena in the dispersion state of the c-IPN cathode

[0211] Experiments were conducted to verify the effect of reducing the surface tension in the electrode slurry, a phenomenon known to alleviate internal stresses caused by drying and thus prevent problems with cracking in electrodes. The results are presented in the Fig. 10A to 10D and 11A to 11C.

[0212] The Fig. 10A to 10D show the following for the electrode slurries (with 30% solids content) prepared in Example 1 (c-IPN), Comparative Example 1 (n-IPN), and Comparative Example 2 (PVDF) of the present invention: (A) surface tension measured using the pendant drop method, (B) absolute zeta potential, (C) micrographs, and (D) laser scanning confocal microscopy (LSCM) images of the surface topography of electrodes (M / A = 50 mg cm -2) prepared from the slurries in Example 1 (c-IPN), Comparative Example 1 (n-IPN) and Comparative Example 2 (PVDF).

[0213] The Fig. 11A to 11B show photographs of the pendant drop tensiometer used to measure the surface tension of the electrode slurries prepared in (A) Comparative Example 2 (PVDF), (B) Comparative Example 1 (n-IPN), and (C) Example 1 (c-IPN) of the present invention.

[0214] As in the Fig. As shown in Figures 10A and 11A to 11C, the electrode slurry in Example 1 (c-IPN) exhibited a lower surface tension compared to the electrode slurries in Comparative Examples. This is because the c-IPN binder acts as an ionic surfactant.

[0215] As in Fig. As shown in Figure 10B, zeta potential analysis was performed on a model suspension (conductive carbon additive / binder = 3 / 5 (w / w) in NMP solvent) prepared at a low concentration of 10 ppm. The results showed that the electrode slurry in Example 1 (c-IPN) exhibited a much higher absolute zeta potential value (~14 mV) compared to Comparative Example with a neutral binder (~1 mV), confirming the cationic nature of the c-IPN binder.

[0216] As in Fig. As shown in Figure 10C, the electrode slurry in Example 1 (c-IPN) exhibited a well-dispersed state, while some particle agglomerates were observed in the electrode slurry of Comparative Examples. This is consistent with the previously described findings that a high absolute zeta potential value in a suspension solution contributes to improving the dispersion state.

[0217] To investigate how the condition of the electrode slurry affects the dispersion uniformity in the dried electrode, laser scanning confocal microscopy (LSCM) analysis was performed to map the surface roughness. The results are presented in the Fig. 12A to 12C.

[0218] The Fig. 12A to 12C show confocal laser scanning microscopy surface topography images of electrodes with a low M / A (= 26 mg cm - 2 ) prepared in (a) Comparative Example 2 (PVDF), (b) Comparative Example 1 (n-IPN) and (c) Example 1 (c-IPN) of the present invention.

[0219] As in the Fig. As shown in Figures 12A to 12C, all electrodes exhibited a low M / A (e.g., 26 mg cm -2 ) has a uniform topography. As in Fig. 10D, however, the electrodes in the comparative examples showed a significant increase in M / A to 50 mg cm -2significant variations due to the non-uniform distribution of the electrode components. These height variations can lead to uneven pressure distribution across the electrode during roll pressing, potentially resulting in dimensional instability and non-uniformity in the electrode. In contrast, the height variations in the electrode from Example 1 (c-IPN) were negligible over a large scan range, which can be attributed to the well-dispersed slurry state. This result confirms the potential role of the c-IPN binder in controlling electrostatic phenomena during slurry casting, which is critical for the production of high M / A ratio electrodes. Experimental Example 4. Structural stability of the c-IPN cathode

[0220] To illustrate the basic properties of the c-IPN binder, films were prepared as described below and their properties were evaluated as described in the Fig. 13A to 13H.

[0221] PVDF film: The PVDF film was prepared by dissolving PVDF in N-methyl-2-pyrrolidone to create a coating solution. This solution was then applied to a substrate and dried to form the film.

[0222] n-IPN film: A coating solution was prepared by adding PVDF and the crosslinking agent TMPTA in a weight ratio of 3:2 to N-methyl-2-pyrrolidone. This coating solution was then applied to a substrate and dried to form the film.

[0223] TMPTA / VAI-TFSI film: A coating solution was prepared by adding the crosslinking agent TMPTA and VAI-TFSI, prepared in Example 1, to N-methyl-2-pyrrolidone in a weight ratio of 0.7:1.3. This coating solution was then applied to a substrate and dried to form the film.

[0224] c-IPN film: A coating solution was prepared by adding PVDF, the crosslinking agent TMPTA, and VAI-TFSI, prepared in Example 1, in a weight ratio of 3:0.7:1.3 to N-methyl-2-pyrrolidone. This coating solution was then applied to a substrate and dried to form the film.

[0225] Fig. Figure 13A shows the Fourier transform infrared (FT-IR) spectra of the c-IPN films before and after thermal cross-linking, focusing on the characteristic peaks assigned to the acrylic C=C bonds.

[0226] As in Fig. 13A, confirms the disappearance of TMTPA (v C=O and v C-H ) and VAI-TFSI (v N-H and v C-F ) as well as the characteristic peaks of the acrylic C=C bonds observed in the Fourier transform infrared (FT-IR) spectra demonstrated the successful synthesis of the cross-linked copolymer network in the c-IPN films.

[0227] The Fig. Figures 14A to 14D show the Differential Scanning Calorimetry (DSC) profiles of the glass transition temperatures (T g ) of pristine PVDF films (A), pristine TMPTA / VAI-TFSI cross-linked copolymer films (B), and c-IPN films (C, D).

[0228] As in the Fig. As shown in Figures 14A to 14D, the c-IPN films exhibited two different glass transition temperatures (-31 °C and 70 °C), which are very close to the temperatures of the pristine PVDF (-35 °C) and the cross-linked copolymer (71 °C), respectively. This indicates phase separation of PVDF and the cross-linked copolymer in the c-IPN, a typical feature of the IPN structure.

[0229] Fig. Figure 13B shows the stress-strain curves for PVDF, n-IPN, and c-IPN films.

[0230] As in Fig. As shown in Figure 13B, the c-IPN and n-IPN films exhibited higher mechanical strength than the PVDF films due to their interpenetrating polymer networks. However, the c-IPN films exhibited higher toughness and lower modulus compared to the n-IPN films. This can be attributed to the loosely cross-linked network formed by the copolymerization of TMPTA (a cross-linking agent with three double bonds) and VAI-TFSI (a monomer with two double bonds). This result suggests that the c-IPN binder can be mechanically resistant to transverse internal stresses induced by solvent drying during electrode fabrication.

[0231] Fig. Figure 13C shows a graph of adhesion strength measured by a 180° peel test as a function of M / A for electrodes prepared in Comparative Example 1 (PVDF), Comparative Example 2 (n-IPN), and Example 1 (c-IPN).

[0232] The Fig. Figures 15A to 15C show the bond strength between the active electrode layers and the Al current collectors for PVDF (A), n-IPN (B), and c-IPN (C) electrodes with different M / A values.

[0233] As in the Fig. 13C and 15A to 15C, the bond strength tended to decrease with increasing M / A. It is noteworthy that when the M / A value was 30 mg cm -2 or higher, there was a significant difference in the adhesion strength between the c-IPN (Example 1) and n-IPN electrodes compared to the PVDF electrodes.

[0234] Fig. Figure 13D shows a micrograph of an electrode used in Comparative Example 1 (PVDF) with an M / A value of 50 mg cm -2was manufactured while Fig. Figure 13E shows a micrograph of an electrode used in Example 1 (c-IPN) with a M / A value of 96 mg cm -2 was manufactured.

[0235] As in the Fig. 13D and Fig. As shown in Figure 13E, the PVDF electrode with an M / A of 50 mg cm -2 severe cracking and delamination, consistent with previously reported results. In contrast, the electrode from Example 1 (c-IPN) maintained its dimensional accuracy without cracking, even at a higher M / A of 96 mg cm -2 .

[0236] Fig. Figure 13F shows a cross-sectional image obtained by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) of an electrode prepared in Example 1 (c-IPN) with an M / A of 96 mg cm -2 was manufactured.

[0237] As in Fig. As shown in Figure 13F, the electrode from Example 1 (c-IPN) exhibits close interfacial contact between the active electrode layer (thickness ~390 µm) and the Al current collector. The elements Ni and C, which originate from NCM811 and carbon black additives / binders, respectively, are uniformly distributed throughout the thickness of the electrode. This confirms that the electrode from Example 1 (c-IPN) maintains its dimensional accuracy without cracking, even at a higher M / A of 96 mg cm. -2.

[0238] Fig. Figure 13G shows plots of thickness and electrode density (ρ) as a function of M / A for the electrode prepared in Example 1 (c-IPN) after roll pressing. Fig. Figure 13H illustrates the electrode density as a function of C / A for the electrodes prepared in Example 1 (c-IPN) compared to previously described high M / A electrodes.

[0239] As in the Fig. 13G and Fig. As shown in Figure 13H, the electrodes from Example 1 (c-IPN) exhibited, in addition to the previously mentioned high M / A, a uniform electrode density of 2.8 g cm -3 over the entire range of M / A values, thus outperforming the high M / A electrodes already described. Experimental Example 5. Uniformity of the redox reaction across the entire thickness of the c-IPN cathode: Maintaining the theoretical C sp by NCM811

[0240] The results of the electrochemical performance evaluation of cells containing cathodes from Comparative Example 1 (n-IPN) and Example 1 (c-IPN) with a 100 µm Li-metal anode (C / A = 20 mAh cm -2 ) are available in the Fig. 16A to 16F, 17A, 17B and 18A to 18C.

[0241] Fig. Figure 16A shows the constant current charge / discharge profiles at 25 °C for cells using cathodes prepared in Example 1 (c-IPN) with different cathode M / A values.

[0242] As in Fig. As shown in Figure 16A, the capacitance (C / A) of the cathodes prepared in Example 1 (c-IPN) increases proportionally with the increase of M / A.

[0243] Fig. 16B shows the specific capacity (C sp ) as a function of M / A for cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) at a discharge current rate of 0.1 C. The dashed line represents the theoretical specific capacity of NCM811 (~210 mAh / g).

[0244] Fig. Figure 17 shows the charge / discharge profiles at constant current as a function of the cathode M / A (26-96 mg cm -2) at charge / discharge current rates of 0.05 C / 0.1 C and within a voltage range of 3.0 to 4.4 V for cells combining cathodes from Comparative Example 1 (n-IPN) (a) and Example 1 (c-IPN) (b) with a Li-metal anode.

[0245] As in the Fig. 16b and Fig. 17, the cathodes prepared from Example 1 (c-IPN) retained the theoretical specific capacity of NCM811 (~210 mAh / g NCM811 ) even at an M / A of 96 mg / cm 2 (corresponding to a C / A of 20 mAh / cm 2 ). In contrast, the cathodes prepared from Comparative Example 1 (n-IPN) exhibited M / A values ​​above 59 mg / cm 2 a sharp decline in specific capacity.

[0246] Fig. 18 includes: (a) A graph showing the discharge rate performance (expressed as C sp) as a function of M / A for cells combining cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) of the present invention with a Li-metal anode. (b) Constant current charge / discharge profiles for cells using high M / A cathodes (65 mg cm -2 ) from Comparative Example 1 (n-IPN) at discharge current rates of 0.05 C (0.68 mA / cm 2 ) to 0.5 C (6.75 mA / cm 2 ). (c) Constant current charge / discharge profiles for cells using high M / A cathodes (65 mg cm -2 ) from Example 1 (c-IPN) at discharge current rates of 0.05 C (0.68 mA / cm 2 ) to 0.5 C (6.75 mA / cm 2 ).

[0247] As in Fig. 18, the difference in C spThe differences between the cathodes prepared from Example 1 (c-IPN) and Comparative Example 1 (n-IPN) were more pronounced at higher discharge current rates and higher M / A values. However, PVDF cathodes were excluded from this comparison because they could not be used to produce cathodes with high M / A values.

[0248] Fig. Figure 16C shows the specific energies of cells with cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) as a function of M / A, excluding the packaging materials.

[0249] The ultimate goal of high M / A ratio electrodes is to achieve high energy density (= voltage × C / A, where C / A = M / A × C sp ). However, as shown in Table 3, previous studies on high M / A ratio electrodes often underestimated the importance of C sp overlook.

[0250] In contrast, as in Fig. 16C and Table 1, by the cathodes prepared in Example 1 (c-IPN), the specific energy of the cells increased continuously with increasing M / A values ​​until finally a plateau of 431 Wh kg -1 at a M / A of 96 mg cm -2 In contrast, the specific energy of cells using cathodes from Comparative Example 1 (n-IPN) decreased when M / A exceeded 59 mg cm -2 increased, which is consistent with the Csp results ( Fig. 16B).

[0251] Fig. Figure 16D shows a light micrograph of the cross section of a cathode (M / A = 65 mg cm -2 ), prepared in Example 1 (c-IPN), after charging at a current density of 1.1 mA cm -2 to 4.4 V and subsequent disassembly. The upper and lower regions shown in the image correspond to the regions selected for Raman spectroscopy, as shown in the Fig. 16e to f and Fig. 20 shown.

[0252] Fig. Figure 16E shows the Raman spectra and the intensity ratio of Eg / A1g for the upper and lower regions of the cathodes prepared in Comparative Example 1 (n-IPN), while Fig. Figure 16F shows the corresponding Raman spectra and the Eg / A1g ratio for cathodes from Example 1 (c-IPN). In this context, Eg and A1g refer to the metal-oxygen-metal bending modes along the a / b axes, where Eg corresponds to the metal-oxygen-metal mode in the a / b directions and A1g represents the stretching mode of the metal-oxygen complexes along the c-axis.

[0253] Fig. Figure 19 shows a light micrograph of a cross-section of a cathode prepared in Comparative Example 1 (n-IPN) with an M / A of 65 mg cm -2 was manufactured.

[0254] To understand the difference in C spTo further explain the difference between the cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN), the state of charge (SOC) was analyzed along the thickness direction. As shown in the Fig. 16D and Fig. As shown in Figure 19, the distance from the Al current collector (labeled “top” and “bottom”) was measured and the local SOC values ​​were investigated as a function of this distance using confocal Raman spectroscopy.

[0255] As in the Fig. 16E-F, the Raman spectra, in which the intensity ratio of E g / A 1g tends to increase with the state of charge (SOC) of the active anode material (ie, the degree of delithiation), that the cathodes prepared in Comparative Example 1 (n-IPN) have a lower E g / A 1gintensity ratio in the lower region. This suggests that NCM811 in these cathodes in the lower region (next to the Al current collector) is not present due to the uneven and tortuous paths for Li + in the cathode undergoes less delithiation. In contrast, the intensity ratio E g / A 1g of the cathodes prepared in Example 1 (c-IPN) are almost constant across the cross-section, confirming the uniformity of the redox reactions of NCM811 throughout the entire thickness.

[0256] The Fig. 20A and Fig. 20B shows the Raman spectra and the intensity ratio of E g / A 1g for cathodes with low M / A (26 mg cm -2 ) prepared in Comparative Example 1 (n-IPN) (a) and Example 1 (c-IPN) (b) after charging at a current rate of 0.2 C (1.1 mA cm -2 ). The spectra are shown for the upper and lower regions of the cathodes.

[0257] As in the Fig. 20A and Fig. As shown in Figure 20B, there is no significant difference in the Eg / A1g ratio between the upper and lower regions of cathodes with low M / A (26 mg cm -2 ) compared to those with high M / A. This suggests that the redox uniformity observed for the cathodes from Example 1 (c-IPN) is more likely due to the Li + -transport than due to electronic conductivity across the thickness.

[0258] Fig. Figure 21 shows a comparison of the electronic conductivity of cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) as a function of M / A. The measurements were performed using a four-point probe station.

[0259] As in Fig. 21, the electronic conductivity of the cathodes at a M / A of 65 mg cm -2negligible, suggesting that the difference in the Eg / A1g intensity ratio between the two cathodes is mainly due to the slower ion transport in the thickness direction of the cathodes prepared in Comparative Example 1 (n-IPN). This result is consistent with previous studies on high M / A ratio electrodes, which emphasize the importance of ion transport in achieving a uniform redox reaction. Experimental example 6. Strengthening the Li + -Conductivity in the cathode through c-IPN binder

[0260] Binders are known to act as adhesives between active cathode materials, and since they do not completely cover the active cathode material, a significant portion of the active material is exposed to the electrolyte. In Example 1, the c-IPN binder can influence the surface charge environment of the electrolyte-filled spaces and pores in the electrode, thus facilitating Li + -transport, as described above. The imidazolium-based cationic groups in the c-IPN binder can interact electrostatically with the anions (PF6 - ) of the liquid electrolyte (1 M LiPF6 in ethyl carbonate (EC) / diethyl carbonate (DEC) = 1 / 1 (v / v)). The experimental results demonstrating this effect are presented in the Fig. 22A to 22G.

[0261] Fig. Figure 22A shows the FT-IR spectra of cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) when in contact with the liquid electrolyte (1M LiPF6 in EC / DEC = 1 / 1 (v / v)). Fig. 22A focuses on the characteristic vibration peak of the PF6 - -Binding at 836 cm -1 .

[0262] As in Fig. As shown in Figure 22A, the cathodes prepared in Example 1 (c-IPN) showed a shift in the vibration peak of the PF6 - -Binding at 836 cm -1 downwards. This indicates that the c-IPN binder in Example 1 has electrostatic interactions between the cationic imidazolium groups and the PF6 - -anions in the liquid electrolyte.

[0263] Fig. 22B presents the results of the 7Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy at the binder-electrolyte interface for cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN).

[0264] As in Fig. 22B, the analysis of the local environment of Li + in the electrolyte-filled pores of the cathodes prepared in Example 1 (c-IPN), a downward shift and a narrower peak in the 7 Li NMR spectrum compared to those of Comparative Example 1 (n-IPN). This observation indicates improved dissociation of Li salts and increased mobility of free Li + -ions in the c-IPN-based cathodes.

[0265] Using the normalized intensity of the 7 Li NMR spectra (I / I0) as a function of time from Fig. 22B, the values ​​of the spin-lattice relaxation time (T1) were determined and are shown in Fig. 23 shown.

[0266] Fig. Figure 23 shows the inversion recovery diagrams obtained from the 7 Li-MAS NMR spectra of cathodes from Example 1 (c-IPN) and Comparative Example 1 (n-IPN) were obtained. Fig. The spin-lattice relaxation time (T1) shown in Figure 23 was calculated using the following equation 6. I=I0(1*exp−t / T1)

[0267] In equation 6, I represents the peak intensity at time t and I0 represents the saturation intensity.

[0268] As in Fig. As shown in Figure 23, the cathodes prepared in Example 1 (c-IPN) exhibited a lower T1 value (737 ms) than those from Comparative Example 1 (n-IPN) (957 ms). Since a lower T1 value reflects a faster ion diffusion rate, this indicates that the cathodes from Example 1 exhibit improved Li + -Mobility in the electrolyte-filled pores.

[0269] The Fig. 22C and Fig. 22D shows the radial distribution function (RDF) profiles of the P atoms of PF6 - and Li atoms at the binder-electrolyte interface for cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN), obtained from electrochemical impedance spectroscopy (EIS) analysis of a symmetric cell (electrode| |electrode) at 0% state of charge (SOC).

[0270] As in Fig. As shown in Figure 22C, the analysis of the radial distribution function (RDF) for PF6 - - and Li + -ions at the binder-electrolyte interface, that for the binder from Comparative Example 1 (n-IPN) the RDF for PF6 - gradually increased with increasing distance (r) from the n-IPN binder surface. In contrast, the binder from Example 1 (c-IPN) showed a clear peak at r = 5.0 Å, indicating that PF6 -is predominantly present on the surface of the cathode prepared in Example 1 (c-IPN).

[0271] As in Fig. As shown in Figure 22D, the analysis of the radial distribution function (RDF) for Li + as a function of r, the binder from Example 1 (c-IPN) exhibited a characteristic peak at a larger r (6.5 Å) compared to the binder from Comparative Example 1 (n-IPN) (2.0 Å). This indicates that the binder from Example 1 (c-IPN) causes Li + -ions are located further away from the binder due to electrostatic repulsion by the positively charged imidazolium groups in the c-IPN binder.

[0272] Electrochemical impedance spectroscopy (EIS) analysis was performed on a symmetric cell to determine the ionic conductivity (σ Elektrode) within the electrolyte-filled pores of the electrode. The results are shown in the Fig. 24A to 24C.

[0273] Furthermore, it is known that the slope observed in the low frequency range of the Nyquist plot reflects the ionic resistance within the electrode (R Ion / 3, (σ Elektrode = 1 / R Ion ). Therefore, WO was used to calculate R Ion / 3, and R Ion was used to calculate the ionic conductivity within the cathode (σ Elektrode = 1 / R ion ).

[0274] The Fig. Figures 24A to 24C show the Nyquist diagrams for symmetric cells (electrode||electrode) using cathodes with high M / A (= 65 mg cm -2 ) that are fully lithiated, as prepared in Comparative Example 1 (n-IPN) (A) and in Working Example 1 (c-IPN) (B). It also includes the equivalent circuit using the generalized Warburg element with open circuit termination of finite length (WO, Warburg Open) [C]. In the Fig. 24 (ab), the symbols and solid lines represent the experimental data and the fitting curves based on the ladder-like equivalent circuit (TLM) model, respectively.

[0275] The Fig. 25A and Fig. 25B illustrate the following for cathodes with high M / A (= 65 mg cm -2 ) prepared in Comparative Example 1 (n-IPN) and Working Example 1 (c-IPN): Profiles of the galvanostatic intermittent titration technique (GITT): (A) These are the GITT profiles under repeated current pulses at a discharge current rate of 0.1 C (= 1.35 mA cm -2 ) are shown. (B) Discharge steps in GITT: The discharge steps obtained from the GITT profiles are shown.

[0276] In Fig. 25, the lithium ion diffusion coefficient (D Li + ) is calculated using the following equation 7, and the specific calculation details are shown in Table 5 below. DLi+=4πΔτ(mBVMMBS)(ΔEsΔEt)2

[0277] In equation 7, m B is the mass of the electrode active material, S is the geometric area of ​​the electrode, M B is the molar mass of the electrode material and V M is the molar volume of the electrode material. Other parameters (Δt, ΔEt and ΔE s )) are in the Fig. 25A and Fig. 25B. [Table 5] Δt M B V M m B S -1 ΔE s DE t D Li- (s) (g mol -1 ) (cm 3 mol -1 ) (mg cm -2 ) (mV) (mV) (cm 2 s -1 ) n-IPN 3600 97.28 20.53 64.56 61.11 158.98 9.69 E-09 c-IPN 3600 97.28 20.53 64.48 51.54 86.51 2.32 E-08

[0278] Fig. Figure 22E shows an Arrhenius diagram of ionic conductivity in electrolyte-filled pores for cathodes (M / A = 65 mg cm -2 ), prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN).

[0279] As in the Fig. As shown in Figures 22E, 24A to 24C, 25A and 25B, the cathode prepared in Example 1 (c-IPN) exhibited a higher σ-electrode and a lower activation energy (E a ) on.

[0280] Fig. 22F shows a diagram showing the internal resistance (R innen ) and D Li + as functions of discharge voltage for the cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) with an M / A ratio of 65 mg cm -2 These data were estimated from the results of the galvanostatic intermittent titration technique (GITT) at 25 °C.

[0281] As in Fig. As shown in Figure 22F and Table 5, the cell with the cathode prepared in Example 1 (c-IPN) exhibited a lower internal resistance (R innen ) and a higher Li +-Diffusion coefficients (D Li + ) over the entire voltage range.

[0282] Fig. Figure 26 shows (a) the weight change and (b) the images before (left) and after (right) electrolyte absorption of the cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) after being immersed in a liquid electrolyte (1M LiPF6 in EC / DEC = 1 / 1 (v / v)) for 2 hours.

[0283] As in Fig. As shown in Figure 26, the difference in electrolyte absorption between the cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) was negligible, indicating that the simple Li + -transport in the cathode prepared in Example 1 (c-IPN) is almost independent of the amount of electrolyte in the cathode.

[0284] Fig. Figure 22g is a schematic diagram illustrating the role of the binder according to one embodiment of the present invention.

[0285] As in Fig. As shown in Figure 22g, the binder according to an embodiment of the present invention is uniformly bonded by electrostatic attraction with PF6 and electrostatic repulsion with Li + in the liquid electrolyte in the cathode, thereby allowing the distribution of freely mobile Li + and a uniform distribution of the Li+ concentration can be facilitated. Experimental Example 7. Improving Cycle Performance through c-IPN and Mechanical Understanding

[0286] Using the cathode (c-IPN) prepared in Example 1, a Li-metal full cell (cathode (C / A = 13.5 mAh cm -2 ) || Li-metal anode (C / A = 20.0 mAh cm -2, N / P ratio = 1.5). The cycling performance of the cell was tested under charge / discharge current densities of 0.68 / 1.35 mA cm -2 and a voltage range of 3.0-4.4 V at 25 °C, and the results are shown in the Fig. 27 and Fig. 28 shown.

[0287] Fig. Figure 27a shows the cycle performance of Li-metal full cells using cathodes (M / A = 65.0 mg cm -2 ) prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN).

[0288] Fig. Figure 28 shows the constant current charge / discharge profiles of Li-metal full cells for the 1st, 50th, and 100th cycles using cathodes prepared in Comparative Example 1 (n-IPN) (a) and Example 1 (c-IPN) (b).

[0289] As in the Fig. 27a and Fig. As shown in Figure 28, the cell with the cathode prepared in Example 1 (c-IPN) had a higher initial C sp (~210 mAh gNCM811 -1 ) than the cell with the cathode from Comparative Example 1 (n-IPN) (~185 mAh g NCM811 - 1 After 100 cycles under restricted cell conditions, the capacity retention was 82% for Example 1 (c-IPN) and 16% for Comparative Example 1 (n-IPN), indicating that the cell with the cathode from Example 1 (c-IPN) demonstrates higher cycling stability.

[0290] To provide a more detailed explanation of the effects of the cathode prepared in Example 1 (c-IPN) on the cycle performance, the EIS spectra of the cells were analyzed and the results presented in the Fig. 29A to 29C and Table 6.

[0291] The Fig. Figures 29A to 29C show the Nyquist diagrams for Li-metal full cells with cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN) during the first (A) and 50th (B) cycles. They also include (C) the equivalent circuit used for the diagrams. Fig. 29 (ab) the symbols and solid lines represent experimental data and fitted curves, respectively.

[0292] Table 6 shows the results of the equivalent circuit analysis as a function of the number of cycles obtained from the Nyquist diagrams in Fig. 29 were won. [Table 6] Kathode Impedance (Ohm cm) -2 ) 1. Zyklus 50. Zyklus n-IPN R Film 9,3 79,8 R ct 17,0 47,0 c-IPN R Film 9,2 23,6 R ct 4,0 33,6

[0293] As in the Fig. As shown in Figures 29A to 29C and Table 6, the cathode prepared in Example 1 (c-IPN) exhibited a lower cell resistance during the first cycle than the cathode in Comparative Example 1 (n-IPN). This indicates that the binder in Example 1 (c-IPN) inhibited the free movement of Li +-ions and leads to a more even distribution of Li + -concentration in the cathode with a high C / A ratio. Furthermore, the lower cell resistance was still observed after the 50th cycle in Example 1 (c-IPN), indicating the formation of a stable CEI in NCM811, which has a positive impact on the cycle performance.

[0294] To investigate the CEI formed on NCM811, NCM811 from cycled cathodes was analyzed by depth profiling using X-ray photoelectron spectroscopy (XPS) as a function of etching time. The results are shown in the Fig. 27B-C and 30A to 30C.

[0295] Fig. Figure 27B shows the XPS (X-ray photoelectron spectroscopy) depth profile of the cycled cathodes prepared in Comparative Example 1 (n-IPN), while Fig. Figure 27C illustrates the XPS depth profile of the cycled cathodes prepared in Example 1 (c-IPN).

[0296] The Fig. Figures 30A to 30C show the XPS (X-ray photoelectron spectroscopy) profiles of cycled NCM811 from cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). Specifically, the C1s (a), F1s (b), and O1s (c) profiles are shown.

[0297] As in the Fig. As shown in Figures 27B, 27C, and 30A to 30C, Comparative Example 1 (n-IPN) exhibited a higher content of organic elements (represented as C and O), mainly due to the decomposition of carbonate solvents in the electrolyte. In contrast, Example 1 (c-IPN) exhibited a higher content of inorganic elements (e.g., Li and F) over a long etching period, due to the formation of a LiF-rich component. A LiF-rich CEI layer is known to mitigate undesirable interfacial side reactions with the electrolyte, which has a positive impact on cycle life.

[0298] Furthermore, the XPS F1s spectrum of the cycled NCM811 from the cathode prepared in Example 1 (c-IPN) shows a predominant presence of LiF (at 685.5 eV). LiF in the CEI layer is known to have a positive influence on cycling stability. This finding is confirmed by the strong peak at 529.8 eV in the O1s spectrum for Comparative Example 1 (n-IPN), which is attributed to MO (metal-oxygen) species and explains the strong dissolution of transition metal ions.

[0299] The Fig. Figures 31A to 31E show the normalized time-of-flight secondary ion mass spectrometry (TOF-SIMS) depth profiling after cycling for cathodes prepared in Comparative Example 1 (n-IPN) (A) and Example 1 (c-IPN) (B). Also shown are TOF-SIMS depth profiles for LiF2 (C), Li2CO3 (D), and C2F (E).

[0300] As in the Fig. As shown in Figures 31A to 31E, the cathode prepared in Example 1 (c-IPN) exhibited lower intensities of organic components (e.g., Li2CO3- and C2F-) in the inner layers and higher intensities of inorganic LiF2 compared to the cathode prepared in Comparative Example 1 (n-IPN). - This indicates that the unique CEI structure of the cathode in Example 1 (c-IPN) is consistent with the results of a LiF-rich CEI layer grown in concentrated electrolytes on LiPF6 - -basis is formed.

[0301] Fig. Figure 27D shows the FT-IR spectra of the liquid electrolyte (1 M LiPF6 in EC / DEC = 1 / 1 (v / v)) used with cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). The spectra focus on the characteristic peaks attributed to the carbonyl stretching vibrations of the EC solvent, particularly at 1770 and 1800 cm -1 .

[0302] As in Fig. As shown in Figure 27D, the differences in the CEI layers of the cathodes prepared in Example 1 (c-IPN) and Comparative Example 1 (n-IPN) were determined by examining the Li + -Solvation structure of the liquid electrolyte in the cathodes was further confirmed. In the FT-IR spectrum of the liquid electrolyte, two characteristic peaks were observed at 1770 and 1800 cm -1 observed, which were assigned to the carbonyl stretching vibrations of the EC solvent for Comparative Example 1 (n-IPN). These peaks corresponded to coordinated and free carbonate species of Li, respectively. + In contrast, in the FT-IR spectrum of Example 1 (c-IPN), the peak at 1770 cm -1 with increasing intensity downwards, indicating an increase in the coordinated carbonates of Li + indicates.

[0303] The Li+ solvent RDF (radial distribution function) analysis and CN (coordination number) calculations were used to estimate the Li + -solvation structure within the liquid electrolyte in the cathodes. The results are shown in the Fig. 32A and Fig. 32B.

[0304] The Fig. 32A and Fig. Figure 32B shows the radial distribution function (RDF) and coordination number (CN) profiles for the binder-electrolyte interfaces (EC (A) and DEC (B)) in the cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). These profiles represent the solvation structure of Li + -ions with the solvents in the liquid electrolyte.

[0305] The Fig. 33A and Fig. Figure 33B illustrates the radial distribution function (RDF) profiles (A) and the coordination numbers (CN) (B) for the binder-electrolyte interface and the bulk electrolyte in cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). The RDF profiles and CN values ​​represent the interactions between Li + - and PF6 - -ions in the liquid electrolyte.

[0306] As in the Fig. 33A and Fig. As shown in Figure 33B, the binder in Example 1 (c-IPN) had a lower coordination number (CN) than the binder and bulk electrolyte in Comparative Example 1 (n-IPN). This indicates that due to the electrostatic interactions between PF6 - and the binder in Example 1 (c-IPN) the PF6 - -ions in the liquid electrolyte in the cathode prepared in Example 1 (c-IPN) are less coordinated by the solvent.

[0307] In other words, the cathode prepared in Example 1 (c-IPN) has a relatively higher coordination number (CN) between Li + and the solvent in the liquid electrolyte, while they have a lower CN between Li + and PF6 - (see Fig. 33A and Fig. 33B). This confirms the presence of electrostatic interactions between PF6 - and the binder in Example 1 (c-IPN).

[0308] The solvation structure of Li + in the liquid electrolyte of the cathode was theoretically investigated using molecular dynamics (MD) simulations, and the results are presented in Table 7.

[0309] Table 7 provides detailed information on the model systems for the binders in Comparative Example 1 (n-IPN) and Example 1 (c-IPN). The initial densities of the systems were obtained from experimental results. [Table 7] Großteil n-IPN Großteil c-IPN n-IPN / Elektrolyt c-IPN / Elektrolyt TMTPA Ketten 17 7 17 7 Anzahl VAI-TFSI Ketten - 10 - 10 EC - - 560 650 DEC - - 308 358 LiPF6 - - 143 166 System size (nm 3 ) 4,1x4,1x4,1 4,4x4,4x4,4 4,1x4,1x14,0 4,4x4,4x14,5

[0310] Fig. Figure 27E is a diagram showing the relative ratio of Li + -Solvation structures within the liquid electrolyte of cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN).

[0311] The Fig. 34A and Fig. 34B illustrate the HOMO (highest occupied molecular orbital) energy levels and the relative ratios of the solvation structures of Li + in the liquid electrolyte (1M / DEC with 1 M LiPF6 = 1 / 1 (v / v)) for the cathodes prepared in Comparative Example 1 (n-IPN) (A) and in Example 1 (c-IPN) (B). The primary solvation structures of Li + are highlighted in red.

[0312] The solvation structures of Li + are denoted as XYZ-(A), where: X is the number of Li + coordinated EC molecules, Y the number of Li +coordinated DEC molecules, Z the number of Li + coordinated PF6 - -ions and A the number of Li + coordinated TFSI- ions.

[0313] As in the Fig. 27E , Fig. 34A and Fig. As shown in Figure 34B, the cathode prepared in Example 1 (c-IPN) had an increased ratio of Li + coordinated carbonates and a reduced ratio of dissociated LiPF6- carbonate complexes. It was observed that the predominant Li + -solvation structure in Example 1 (c-IPN) was a 5-0-0 configuration (Li + coordinated with 5 EC solvents, 0 DEC solvents and 0 PF6 - ). In contrast, the solvation structure in the cathode prepared in Comparative Example 1 (n-IPN) was a 3-0-2 configuration.

[0314] The HOMO (Highest Occupied Molecular Orbital) energy levels of the primary Li + Solvation structures were determined using density functional theory (DFT) calculations, as described in Fig. 27F.

[0315] Fig. Figure 27F illustrates the (f) HOMO (Highest Occupied Molecular Orbital) energy levels of the primary Li + -solvation structures and (g) the binding energies between the electrolyte components (PF6 - and EC) and Li + for the cathodes prepared in Comparative Example 1 (n-IPN) and Example 1 (c-IPN).

[0316] As in the Fig. As shown in Figures 27F-27G, the solvation structure of the cathode prepared in Example 1 (c-IPN) exhibited lower HOMO energy levels than that of Comparative Example 1 (n-IPN). This is attributed to the difficulty in oxidizing the coordination complexes near the binder in Example 1 (c-IPN). In addition, the 5-0-1-Li+ -Solvation structure in Example 1 (c-IPN) compared to Comparative Example 1 (n-IPN) lower binding energies between Li + and PF6 - This suggests that PF6 - in Example 1 (c-IPN) due to electrostatic interactions with the binder weakly bound to Li + Consequently, PF6- adjacent to the binder in the cathode prepared in Example 1 (c-IPN) is more susceptible to decomposition, promoting the formation of a LiF-rich CEI layer. Experimental Example 8. Structural properties of cyclized NCM811

[0317] The structural changes in the cycled NCM811 were analyzed using focused ion beam tomography (FIB) and high-resolution transmission electron microscopy (HR-TEM), with the results presented in the Fig. 35A to 35H, 36A and 36B.

[0318] The Fig. 35A to 35H show the following for the cycled NCM811 in cathodes prepared in Comparative Example 1 (n-IPN) (A, C, E, G) and Example 1 (c-IPN) (B, D, F, H): scanning electron microscopy (SEM) images of cross sections (A, B), high-resolution transmission electron microscopy (HR-TEM) images (C, D), fast Fourier transform (FFT) patterns (E, F).

[0319] The Fig. 36A and Fig. 36B shows cross-sectional scanning electron microscopy (SEM) images of cycled NCM811 particles in the cathodes prepared in Comparative Example 1 (n-IPN) (a) and Example 1 (c-IPN) (b).

[0320] As in the Fig. 36A and Fig. As shown in Figure 36B, the penetration of electrolyte into the grain boundary cracks can continuously induce the formation of new primary particles and undesirable interfacial side reactions, potentially affecting the cycling stability.

[0321] As in the Fig. 35A, Fig. 36A and Fig. As shown in Figure 36B, the cycled NCM811 in the cathodes prepared in Comparative Example 1 (n-IPN) exhibited significant grain boundary cracks along with microcracks due to anisotropic deformation. In contrast, the cycled NCM811 in the cathodes prepared in Example 1 (c-IPN) maintained structural integrity with no noticeable cracks or discontinuities.

[0322] As in the Fig. As shown in Figures 35C and D, the cycled NCM811 in the cathodes prepared in Example 1 (c-IPN) exhibited a thin and uniform CEI layer. In contrast, the cycled NCM811 in the cathodes prepared in Comparative Example 1 (n-IPN) exhibited a thick and uneven CEI layer.

[0323] As in the Fig. As shown in Figures 35E to G, the layered structure of the cycled NCM811 in the cathodes prepared in Comparative Example 1 (n-IPN) was almost completely lost, which was confirmed by the FFT (Fast Fourier Transform) patterns indicating an amorphous phase. In contrast, the cycled NCM811 in the cathodes prepared in Example 1 (c-IPN) retained its initial layered structure (R3m phase) in the bulk region (in the Fig. 35F and H (area no. 1) remained stable, while in a thin outer layer (~6 nm, area no. 2) a NiO-type rock salt structure (Fm3m phase) was observed. The structural stability of the cycled NCM811 in the cathodes prepared in Example 1 (c-IPN) can be compared to the Fig. Explain the capacity recovery of the two-layer pouch cells shown in Figure 2D. Experimental Example 9. Structural properties of cyclized NCM811

[0324] The Fig. 37A and Fig. 37B illustrate the following: (A) Photographs of the cathodes fabricated in Comparative Example 1 (PVdF), Example 1 (TMPTA), Example 2 (TPPTA), and Example 3 (ETPTA), along with their critical crack thickness (CCT) and critical delamination thickness (CDT). (B) Plots showing the volume resistivity (R bulk ) and the interface resistance (R interfacial ) of the cathodes prepared in Example 1 (TMPTA) and Example 3 (ETPTA).

[0325] As in Fig. As shown in Figure 37A, it is obvious that the cracking phenomenon is significantly suppressed in the embodiments of the present invention compared to Comparative Example 1 using PVDF alone. Furthermore, the delamination of the electrode layer having the largest molecular weight observed in Example 2 (TPPTA) is significantly different from other examples because the length and molecular weight of the crosslinking agent increase in the order of TMPTA → ETPTA → TPPTA. This is because as the length and molecular weight of the crosslinking agent increase, the elastic modulus decreases, which accelerates the delamination phenomenon after roll pressing.

[0326] As in Fig. 37B, it can be observed that of Example 1 (TMPTA) and Example 3 (ETPTA), Example 1 (TMPTA) has a significantly reduced interfacial resistance.

[0327] Although the embodiments of the present invention have been described, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit of the invention as defined in the claims. Such modifications, including additions, changes, or deletions of components, are intended to be within the scope of the invention.

[0328] The references cited in the experimental examples of the description of the present invention are as follows: 1. Choi, J. W & Aurbach, D. Promise and reality of post-lithium-ion batteries with high energy densities. Nat. Rev. Mater. 1.1 (2016). 2. Albertus, P., Babinec, S., Litzelman, S. & Newman, A. Status and challenges in enabling the lithium metal electrode for high-energy and low-cost rechargeable batteries. Nat. Energy 3, 16-21 (2017). 3. Wu, J. et al. From Fundamental Understanding to Engineering Design of High-Performance Thick Electrodes for Scalable Energy- Storage Systems. Adv. Mater. 33, e2101275 (2021). 4. Kim, J. H., Kim, J. M., Cho, S. K., Kim, N. Y.& Lee, S. Y. Redox- homogeneous, gel electrolyte-embedded high-mass-loading cathodes for high-energy lithium metal batteries. Nat. Commun. 13, 2541 (2022). 5. Kuang, Y, Chen, C., Kirsch, D. & Hu, L. Thick Electrode Batteries: Principles, Opportunities, and Challenges. Adv. Energy Mater. 9 (2019). 6. Park, S.-H. et al. High areal capacity battery electrodes enabled by segregated nanotube networks. Nat. Energy 4, 560-567 (2019). 7. Routh, A. F. Drying of thin colloidal films. Rep. Prog. Phys. 76, 046603 (2013). 8. Du, Z., Wood, D. L., Daniel, C., Kalnaus, S. & Li, J. Understanding limiting factors in thick electrode performance as applied to high energy density Li-ion batteries. J. Appl. Electrochem. 47, 405- 415 (2017). 9. Heubner, C., Schneider, M. & Michaelis, A. Diffusion-Limited C-Rate: A Fundamental Principle Quantifying the Intrinsic Limits of Li-Ion Batteries. Adv. Energy Mater. 10 (2019). 10. Park, K.-Y. et al. Understanding capacity fading mechanism of thick electrodes for lithium-ion rechargeable batteries. J. Power Sources 468, 228369 (2020). 11. Zhao, Z. et al. Sandwich, Vertical-Channeled Thick Electrodes with High Rate and Cycle Performance. Adv. Funct. Mater. 29, 1809196 (2019). 12. Chen, C. et al. Highly Conductive, Lightweight, Low-Tortuosity Carbon Frameworks as Ultrathick 3D Current Collectors. Adv. Energy Mater. 7, 1700595 (2017). 13. Wu, J. et al. Ultrahigh-Capacity and Scalable Architected Battery Electrodes via Tortuosity Modulation. ACS Nano 15, 19109 (2021). 14. Chen, S. et al. Critical Parameters for Evaluating Coin Cells and Pouch Cells of Rechargeable Li-Metal Batteries. Joule 3, 1094-1105 (2019). 15. Liu, J. et al. Pathways for practical high-energy long-cycling lithium metal batteries. Nat. Energy 4, 180-186 (2019). 16. Noh, H.-J., Youn, S., Yoon, C. S. & Sun, Y.-K. Comparison of the structural and electrochemical properties of layered Li[NixCoyMnz] O2 (x = 1 / 3, 0.5, 0.6, 0.7, 0.8 and 0.85) cathode material for lithium- ion batteries. J. Power Sources 233, 121-130 (2013). 17. Russel, W. B. Cracking in Drying Latex Films. Langmuir 21, 4938 (2005). 18. Kim, N. Y. et al. Amphiphilic Bottlebrush Polymeric Binders for High-Mass-Loading Cathodes in Lithium-Ion Batteries. Adv. Energy Mater. 12, 2102109 (2021). QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Choi, J. W & Aurbach, D. Promise and reality of post-lithium-ion batteries with high energy densities. Nat. Rev. Mater. 1.1 (2016

[0328] Albertus, P., Babinec, S., Litzelman, S. & Newman, A. Status and challenges in enabling the lithium metal electrode for high-energy and low-cost rechargeable batteries. Nat. Energy 3, 16-21 (2017

[0328] Wu, J. et al. From Fundamental Understanding to Engineering Design of High-Performance Thick Electrodes for Scalable Energy-Storage Systems. Adv. Mater. 33, e2101275 (2021

[0328] Kim, J. H., Kim, J. M., Cho, S. K., Kim, N. Y.& Lee, S. Y. Redox- homogeneous, gel electrolyte-embedded high-mass-loading cathodes for high-energy lithium metal batteries. Nat. Commun. 13, 2541 (2022

[0328] Kuang, Y, Chen, C., Kirsch, D. & Hu, L. Thick Electrode Batteries: Principles, Opportunities, and Challenges. Adv. Energy Mater. 9 (2019

[0328] Park, S.-H. et al. High areal capacity battery electrodes enabled by segregated nanotube networks. Nat. Energy 4, 560-567 (2019

[0328] Routh, A. F. Drying of thin colloidal films. Rep. Prog. Phys. 76, 046603 (2013

[0328] Du, Z., Wood, D. L., Daniel, C., Kalnaus, S. & Li, J. Understanding limiting factors in thick electrode performance as applied to high energy density Li-ion batteries. J. Appl. Electrochem. 47, 405- 415 (2017

[0328] Heubner, C., Schneider, M. & Michaelis, A. Diffusion-Limited C-Rate: A Fundamental Principle Quantifying the Intrinsic Limits of Li-Ion Batteries. Adv. Energy Mater. 10 (2019

[0328] Park, K.-Y. et al. Understanding capacity fading mechanism of thick electrodes for lithium-ion rechargeable batteries. J. Power Sources 468, 228369 (2020

[0328] Zhao, Z. et al. Sandwich, Vertical-Channeled Thick Electrodes with High Rate and Cycle Performance. Adv. Funct. Mater. 29, 1809196 (2019

[0328] Chen, C. et al. Highly Conductive, Lightweight, Low-Tortuosity Carbon Frameworks as Ultrathick 3D Current Collectors. Adv. Energy Mater. 7, 1700595 (2017

[0328] Wu, J. et al. Ultrahigh-Capacity and Scalable Architected Battery Electrodes via Tortuosity Modulation. ACS Nano 15, 19109 (2021

[0328] Chen, S. et al. Critical Parameters for Evaluating Coin Cells and Pouch Cells of Rechargeable Li-Metal Batteries. Joule 3, 1094-1105 (2019

[0328] Liu, J. et al. Pathways for practical high-energy long-cycling lithium metal batteries. Nat. Energy 4, 180-186 (2019

[0328] Noh, H.-J., Youn, S., Yoon, C. S. & Sun, Y.-K. Comparison of the structural and electrochemical properties of layered Li[NixCoyMnz] O2 (x = 1 / 3, 0.5, 0.6, 0.7, 0.8 and 0.85) cathode material for lithium- ion batteries. J. Power Sources 233, 121-130 (2013

[0328] Russel, W. B. Cracking in Drying Latex Films. Langmuir 21, 4938 (2005

[0328] Kim, N. Y. et al. Amphiphilic Bottlebrush Polymeric Binders for High-Mass-Loading Cathodes in Lithium-Ion Batteries. Adv. Energy Mater. 12, 2102109 (2021

[0328]

Claims

[1] Binder for secondary battery electrodes, wherein the binder comprises a cationic semi-interpenetrating network (semi-IPN) polymer. [2] The binder for secondary battery electrodes according to claim 1, wherein the cationic semi-interpenetrating network (semi-IPN) polymer comprises a crosslinked polymer and a linear polymer. [3] The binder for secondary battery electrodes according to claim 2, wherein the crosslinked polymer comprises a cationic unit derived from a cationic monomer and a multifunctional crosslinking unit derived from a multifunctional crosslinking monomer. [4] The binder for secondary battery electrodes according to claim 3, wherein the cationic monomer includes one or more cationic groups selected from the group consisting of imidazolium, pyridinium, phosphonium, sulfonium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, methylium and morpholinium groups. [5] The binder for secondary battery electrodes according to claim 4, wherein the cationic monomer further includes a counter ion, and the counter ion is selected from the group consisting of BF4-, B(CN)4-, CH3BF3-, CH2CHBF3-, CF3BF3-, C2F5BF3-, n-C3F7BF3-, n-C4F9BF3-, PF6-, CF3CO2-, CF3SO3-, N(SO2CF3)2-(TFSI-), N(COCF3)(SO2CF3)-, N(SO2F)2-, N(CN)2-, C(CN)3-, SCN-, and SeCN-. [6] The binder for secondary battery electrodes according to claim 3, wherein the multifunctional crosslinking monomer includes at least two polymerizable functional groups. [7] The binder for secondary battery electrodes according to claim 3, wherein the multifunctional crosslinking monomer is selected from the group consisting of ethylene glycol diacrylate (EGDMA), triethylene glycol diacrylate (TEGDA), poly(ethylene glycol) diacrylate (PEGDA), 1,6-hexanediol diacrylate (HDDA), ethoxylated trimethylolpropane triacrylate (ETPTA), trimethylolpropane propoxylate triacrylate (TPPTA), pentaerythritol triacrylate (PETA) and trimethylolpropane triacrylate (TMPTA). [8] The binder for secondary battery electrodes according to claim 2, wherein the crosslinked polymer is obtained by polymerizing the cationic monomer and the multifunctional crosslinking monomer in a weight ratio of 0.8 to 7:

1. [9] The binder for secondary battery electrodes according to claim 2, wherein the crosslinked polymer is represented by the following chemical formula 1.wherein n and m represent the polymerization degrees of each monomer unit, where n is an integer of 1 to 400 and m is an integer of 1 to 200. [10] The binder for secondary battery electrodes according to claim 2, wherein the linear polymer is selected from the group consisting of cellulose-based polymers, acrylic-based polymers and fluorine-containing polymers. [11] The binder for secondary battery electrodes according to claim 2, wherein the linear polymer is included in an amount of 45 to 100 parts by weight based on 40 parts by weight of the crosslinked polymer. [12] An electrode comprising the binder for secondary battery electrodes according to any one of claims 1 to 11. [13] The electrode according to claim 12, wherein the binder for secondary battery electrodes is included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the entire electrode. [14] A secondary battery comprising an electrode according to any one of claims 12 to 13. [15] A device comprising the secondary battery according to claim 14, wherein the device is selected from the group consisting of a communication device, a transportation device and an energy storage device. [16] A method of manufacturing a secondary battery electrode, the method comprising: (a) preparing an electrode slurry by adding a binder and an electrode active material to a solvent; and (b) obtaining the electrode by applying the electrode slurry, wherein the binder includes a cationic monomer, a crosslinking monomer containing a multifunctional group, and a linear polymer. [17] A method for producing a secondary battery electrode according to claim 16, wherein the electrode slurry further includes a curing agent. [18] A method for producing a secondary battery electrode according to claim 16, wherein the method further comprises (c) a step of heat-treating the coated electrode slurry at 25 to 120°C after the step (b). [19] Binder for a secondary battery electrode comprising a cationic semi-interpenetrating network polymer (semi-IPN), wherein the cationic semi-interpenetrating network (semi-IPN) polymer comprises a cross-linked polymer and a linear polymer, where the crosslinked polymer is obtained by polymerizing a cationic monomer and a multifunctional crosslinking monomer, and wherein the cationic monomer comprises both (vinylbenzyl)trimethylammonium chloride and 1-methyl-1-(4-nitrobenzyl)piperidinium chloride. [20] Binder for a secondary battery electrode comprising a cationic semi-interpenetrating network polymer (semi-IPN), wherein the cationic semi-interpenetrating network (semi-IPN) polymer comprises a cross-linked polymer and a linear polymer, where the crosslinked polymer is obtained by polymerizing a cationic monomer and a multifunctional crosslinking monomer, and wherein the cationic monomer comprises both 1-vinyl-3-allylimidazolium bis(trifluoromethanesulfonyl)imide (VAI-TFSI) and 1,3-bis(2,4,6-trimethylphenyl)imidazolium chloride.

Images