Novel polynaphthalimide, electrode containing the same, and lithium-ion battery containing the same

Abstract

The following equation (I) [Formula 1] A novel polynaphthalimide having a repeating unit represented by JPEG2026511996000024.jpg28150 is disclosed, where A is a cyano-substituted arylamine moiety. Electrodes and lithium-ion batteries comprising the same are also provided.

Description

[Technical Field]

[0001] Cross-referencing of related technologies This application claims the benefit as of the filing date of U.S. Provisional Patent Application No. 63 / 458,242, filed on April 10, 2023, under 119(e)(1) of the U.S. Patent Act. [Background technology]

[0002] The present invention relates to a novel polynaphthalimide, an electrode containing the same, and a lithium-ion battery containing the same.

[0003] Lithium-ion batteries (LiBs) have played a crucial role in portable energy storage devices, replacing many other energy storage systems due to a series of advantageous effects such as lightweight design, high energy density, rapid charging capability, and low self-discharge rate. Aside from these technological advancements, the use of inorganic electrode materials in LiBs is hindered by limited sources of elements not abundant on Earth, excessive costs, and environmental concerns. Furthermore, these materials typically suffer from serious structural degradation and oxygen loss during long-term cycle processes (especially for metal-rich layered cathodes). Therefore, the use of sustainable and environmentally friendly materials is strongly recommended.

[0004] Organic materials are attracting attention as alternative electrodes for next-generation lithium-ion batteries (LiBs) due to their high abundance, low cost, structural diversity, tunable electronic properties, and environmental inertness. Despite these advantageous effects, organic electrode materials generally suffer from problems with structural reversibility and stability, particularly for small organic molecules, due to their high solubility in electrolytes, which reduces overall performance and thus the long cycle life required. Polymerizing small organic compounds is an effective solution to prevent so-called electrode dissolution in non-aqueous electrolytes, thus improving the structural integrity of these organic materials.

[0005] Polyimides are known as high-performance polymer materials due to their thermal stability, solvent resistance, good electrical and mechanical properties, and high chemical resistance. The redox-active carbonyl groups in polyimides, acting as cathode materials, are involved in the accumulation of Li ions through the formation of a two-electron enolization reaction process. Polyimide cathode materials achieve improved cycle stability compared to smaller molecular imide analogs. On the other hand, the low operating potential (2.0-2.5V) of polyimide cathodes based on the enolization process significantly hinders their practical application.

[0006] Therefore, it is desirable to provide novel polyimide analogs applicable to lithium-ion batteries. [Overview of the Initiative]

[0007] The present invention relates to the following formula (I) [ka] This provides a novel polynaphthalimide having a repeating unit represented by , where A is a cyanosubstituted arylamine moiety.

[0008] The present invention also provides an electrode comprising a current collector and an electrode material disposed on the current collector and containing the polynaphthalimide described above.

[0009] The present invention further provides a lithium-ion battery comprising the above-mentioned electrode, a counter electrode positioned opposite the electrode, and an electrolyte positioned between the electrode and the counter electrode.

[0010] Other novel features of this disclosure will become more apparent from the following detailed description when considered in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0011] [Figure 1A] Figure 1A shows the cyclic voltammetry of the TPA-PNI electrode as a cathode at a scan speed of 0.1 mVs-1. [Figure 1B]Figure 1B shows the cyclic voltammetry of the TPA-PNI electrode as a cathode at a scan speed of 0.1 mVs-1. [Figure 1C] Figure 1C shows the cyclic voltammetry of the TPA-PNI electrode as a cathode at a scan speed of 0.1 mVs-1. [Figure 1D] Figure 1D shows the cyclic voltammetry of the TPA-PNI electrode as an anode at a scan speed of 0.1 mVs-1. [Figure 1E] Figure 1E shows the cyclic voltammetry of the TPA-PNI electrode as an anode at a scan speed of 0.1 mVs-1. [Figure 1F] Figure 1F shows the cyclic voltammetry of the TPA-PNI electrode as an anode at a scan speed of 0.1 mVs-1. [Figure 2A] Figure 2A shows the capacitance profile of the TPA-PNI cathode at a current density of 50 mAg-1. [Figure 2B] Figure 2B shows the rate performance of the TPA-PNI cathode. [Figure 2C] Figure 2C shows the long-term cycle performance of the TPA-PNI cathode in 2000mAg-1. [Figure 3A] Figure 3A shows the capacitance profile of the TPA-PNI anode at a current density of 100 mAg-1. [Figure 3B] Figure 3B shows the rate performance of the TPA-PNI anode. [Figure 3C] Figure 3C shows the long-term cycle performance of the TPA-PNI anode in 5000mAg-1. [Figure 4A] Figure 4A shows typical CV curves of the PNI-1 cathode at various scan speeds. [Figure 4B] Figure 4B shows typical CV curves of the PNI-2 cathode at various scan speeds. [Figure 4C] Figure 4C shows typical CV curves of the PNI-3 cathode at various scan speeds. [Figure 4D] Figure 4D shows the contribution of charge accumulation to the PNI-1 cathode over different voltage ranges. [Figure 4E] Figure 4E shows the contribution of charge accumulation to the PNI-2 cathode over different voltage ranges. [Figure 4F] Figure 4F shows the contribution of charge accumulation in the PNI-3 cathode over different voltage ranges. [Figure 5A] Figure 5A shows the Nyquist plot of PNI-1 at various temperatures. [Figure 5B] Figure 5B shows the Nyquist plot of PNI-2 at various temperatures. [Figure 5C] Figure 5C shows the Nyquist plot of PNI-3 at various temperatures. [Figure 5D] Figure 5D shows the Logi0 vs. 1000 / T plots for PNI-1, PNI-2, and PNI-3. [Figure 6A] Figure 6A shows the CV curve of a binder-free PNI-1 cathode. [Figure 6B] Figure 6B shows the CV curve of a binder-free PNI-2 cathode. [Figure 6C] Figure 6C shows the capacitance profiles of the binder-free PNI-1 and binder-free PNI-2 cathodes at 50 mAg-1. [Figure 6D] Figure 6D shows the rate performance of binder-free PNI-1 and binder-free PNI-2 cathodes. [Figure 6E] Figure 6E shows the long-term cycle performance of binder-free PNI-1 and binder-free PNI-2 cathodes at 2000mAg-1. [Modes for carrying out the invention]

[0012] The following embodiments have been prepared to clearly illustrate the above-mentioned and other technical content, features and / or effects of this disclosure when read in conjunction with the accompanying drawings. Through the description of the specific embodiments, readers may further understand the technical means and effects employed by this disclosure to achieve the above-mentioned objectives. Furthermore, all equivalent modifications or variations that do not depart from the concepts of this disclosure are included in the attached claims so that the content disclosed herein can be easily understood and implemented by those skilled in the art.

[0013] Furthermore, in this specification, unless otherwise specified, a value may be interpreted as encompassing a range within ±10% of the value, in particular a range within ±5% of the value, and unless otherwise specified, a range may be interpreted as consisting of multiple subranges defined by the smaller endpoint, the smaller quartile, the median, the larger quartile, and the larger endpoint.

[0014] The present invention relates to the following formula (I) [ka] This provides a novel polynaphthalimide having a repeating unit represented by , where A is a cyanosubstituted arylamine moiety.

[0015] In one embodiment, polynaphthalimide is given by the following formula (I') [ka] It can be represented by , where A is a cyanosubstituted arylamine moiety and n is an integer in the range of 5 to 10000.

[0016] In one embodiment, A may be a cyanosubstituted phenylamine moiety or a cyanosubstituted phenylenediamine moiety.

[0017] In one embodiment, A is given by the following formula (II) [ka] It can be represented by, where X is combined or [ka] And Y is combined or [ka] And, however, N in X or Y is not bound to N in equation (II).

[0018] In one embodiment, A is given by the following formula (II-1) [ka] It may also be expressed by, where X is conjugated or [ka] And Y is combined or [ka] And, however, the N in X or Y is not bound to the N in equation (II-1).

[0019] In one embodiment, the repeating unit of polynaphthalimide is given by the following formulas (I-1), (I-2), and (I-3) [ka] It can be any one of the following:

[0020] In one embodiment of the present invention, the polynaphthalimide having repeating units represented by formula (I-1), (I-2), or (I-3) is a naphthalenetetracarboxylic dianhydride (NTDA) of the following formula (III-1), (III-2), or (III-3) [ka] These can be prepared by reacting them with diamine monomers represented by .

[0021] The present invention also provides an electrode comprising a current collector and an electrode material disposed on the current collector and containing any of the above-mentioned polynaphthalimides.

[0022] In one embodiment, the electrode may be a cathode.

[0023] In one embodiment, the electrode may be an anode.

[0024] In one embodiment, the electrode material may further contain an active material, conductive carbon, and a binder, and the average mass loading of polynaphthalimide is 0.2 mg / cm³. 2 ~1.0 mg / cm³ 2 This is within the range. In one embodiment, based on the total weight of the electrode material, the active material content may be 20% to 60% by weight, the conductive carbon content may be 30% to 70% by weight, and the binder content may be 2% to 15% by weight.

[0025] In one embodiment, the electrode material may further contain an active material and conductive carbon, and the average mass load of polynaphthalimide is 0.2 mg / cm³. 2 ~1.0 mg / cm³ 2 The range is such that no other binders are present in the electrode material. In this embodiment, polynaphthalimide may be used as the binder. In one embodiment, the active material content may be 20% to 70% by weight, and the conductive carbon content may be 30% to 80% by weight, based on the total weight of the electrode material.

[0026] In one embodiment, when the electrode is the cathode, the active material may be lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMn2O4), lithium iron phosphate (LiFePO4), lithium nickel manganese cobalt oxide (LiNiMnCoO2), or a combination thereof. However, the present invention is not limited to these, and any known active material used in the cathode of a lithium-ion battery may be used as the anode material of the present invention.

[0027] In one embodiment, when the electrode is the anode, the active material may be graphite, carbon fiber, carbon nanotube, or a combination thereof. However, the present invention is not limited thereto, and any known active material used in the anode of a lithium-ion battery may be used as the cathode material of the present invention.

[0028] In one embodiment, the binder may be polyvinylidene difluoride (PVDF), styrene-butadiene rubber (SBR), carboxymethylcellulose (CMC), or a combination thereof. However, the present invention is not limited thereto, and any known binder used in lithium-ion batteries may be used in the electrodes of the present invention.

[0029] In one embodiment, when polynaphthalimide is used as a binder, no other binders are present in the electrode except for the polynaphthalimide of the present invention.

[0030] The present invention further provides a lithium-ion battery comprising any of the above electrodes, a counter electrode positioned opposite to the electrode, and an electrolyte positioned between the electrode and the counter electrode.

[0031] In one embodiment, the electrolyte may include a lithium salt. Examples of lithium salts may include, but are not limited to, LiBF4, LiPF6, LiAsF6, LiClO4, or combinations thereof. Other known lithium salts for lithium-ion batteries may be used in the present invention.

[0032] In one embodiment, the electrolyte may also include a solvent. Examples of solvents may include, but are not limited to, ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), or combinations thereof. Other known solvents for lithium-ion batteries may be used in the present invention. Embodiments

[0033] material 4,4'-Diamino-4''-cyanotriphenylamine (diamine-1 represented by formula (III-1) above), N,N-bis(4-aminophenyl)-N',N'-di(4-cyanophenyl)-1,4-phenylenediamine (diamine-3 represented by formula (III-3) above), and N,N'-di(4-nitrophenyl)-1,4-phenylenediamine are performed using previously reported procedures (L. Li, R. Kikuchi, M.-A. Kakimoto, M. Jikei, and A. Takahashi, High It was synthesized according to Perform.Polym. 2005, 17, 135-147; GSLiou, CWChang, HJYen, JPPan, CRYang, THWang, JMHsu (Industrial Technology Research Institute ITRI), U.S. Patent No. 8088932, 2012; and I.Rozalska, P.Kulyk and I.Kulszewicz-Bajer, New J.Chem. 2004, 28, 1235-1243). Commercially available aromatic tetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA) (TCI), was purified by vacuum sublimation. Carbon black, conductive carbon (superP®, over 99% (metallic basis)), polyvinylidene fluoride (PVDF, Alfa Aesar), N-methylpyrrolidone (NMP, over 99%, Thermo Fisher Scientific), and 1M lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC) and diethyl carbonate (DEC) (1:1 (v / v)) were purchased from UBIQ Technology. All materials were used as received without further purification.

[0034] Preparation of N,N’-Bis(4-nitrophenyl)-N,N’-di(4-cyanophenyl)-1,4-phenylenediamine To a solution of 7.32 g (20.88 mmol) of N,N’-di(4-nitrophenyl)-1,4-phenylenediamine and 5.37 g (43.87 mmol) of 4-fluorobenzonitrile in 70 mL of dry dimethyl sulfoxide (DMSO), 6.96 g (45.37 mmol) of dry cesium fluoride was added in one portion with stirring, and the mixture was heated at 150 °C for 24 hours under a nitrogen atmosphere. The mixture was poured into methanol / water, and the precipitated red powder was collected by filtration and reprecipitated with N,N-dimethylformamide / methanol. The product was filtered to obtain 8.58 g of orange crystals (yield 74%) having a mp of 349 - 351 °C. FT-IR (KBr): 1312, 1584 cm -1 (NO2 stretch), 2223 cm -1 (C≡N stretch). 1 H NMR (500 MHz, DMSO-d6, δ, ppm): 7.19 (d, J = 9.2 Hz, 4H), 7.29 (s, 4H), 7.31 (d, J = 8.8 Hz, 4H), 7.83 (d, J = 8.8 Hz, 4H), 8.18 (d, J = 9.2 Hz, 4H). 13 C NMR (125 MHz, DMSO-d6, δ, ppm): 105.87, 118.59 (-C≡N), 121.51, 124.18, 125.50, 128.45, 133.94, 141.52, 142.33, 149.34, 151.70. Anal. Calcd (%) for C 32 H 20 N6O4(552.54): C, 69.56; H, 3.65; N, 15.21. Found: C, 69.32; H, 4.19; N, 15.15.

[0035] Preparation of N,N'-Bis(4-aminophenyl)-N,N'-di(4-cyanophenyl)-1,4-phenylenediamine (diamine-2 represented by formula (III-2) above) In a 250 mL three-necked round-bottom flask equipped with a stirring bar, 9.78 g (17.71 mmol) of N,N'-bis(4-nitrophenyl)-N,N'-di(4-cyanophenyl)-1,4-phenylenediamine and 0.40 g of 10% Pd / C were dissolved / suspended in 100 mL of tetrahydrofuran under a nitrogen atmosphere. The suspension was heated under reflux, and 5.0 mL of hydrazine monohydrate was slowly added to the mixture. After stirring the solution at reflux temperature for 9 hours, the solution was filtered to remove Pd / C, and the filtrate was cooled. The product was collected by filtration and dried under reduced pressure at 80 °C to obtain 8.34 g of bright yellow powder with a mp of 278-283 °C (yield 96%). FT-IR (KBr): 3359, 3444 cm -1 (NH stretch), 2220 cm -1 (C≡N stretch). 1 H NMR (500 MHz, DMSO-d6, δ, ppm): 5.26 (s, 4H, -NH2), 6.62 (d, J = 8.6 Hz, 4H), 6.74 (d, J = 9.0 Hz, 4H), 6.92 (d, J = 8.6 Hz, 4H), 7.18 (s, 4H), 7.52 (d, J = 9.0 Hz, 4H). 13 C NMR (125 MHz, DMSO-d6, δ, ppm): 99.04, 114.96, 116.31, 119.77 (-C≡N), 126.70, 128.61, 132.72, 133.15, 141.93, 147.55, 151.90. Anal. Calcd (%) for C 32 H 24 N6(492.57): C, 78.03; H, 4.91; N, 17.06. Found: C, 77.71; H, 5.34; N, 17.12.

[0036] Preparation of polynaphthalimide (PNI) by a one-step method Three types of naphthenic polyimides (polynaphthalimides; PNI) represented by the above formulas (I-1) to (I-3) were synthesized from diamine monomers and NTDA dianhydrides. The general synthesis route is shown using the synthesis of PNI-2, represented by the above formula (I-2), as an example. 753.8 mg (1.54 mmol) of diamine-2 was added in a single solution to 7.0 mL of m-cresol, to which 410.4 mg (1.54 mmol) of NTDA was added, followed by the addition of 752.5 mg of benzoic acid. The mixture was heated at 80°C for 2 hours, and then at 210°C for 15 hours. The resulting polymer solution was slowly poured into 300 mL of stirred methanol to produce a brown fibrous precipitate, which was collected by filtration, thoroughly washed with methanol, and dried under vacuum at 100°C. For further purification, the polymer was reprecipitated twice with N-methyl-2-pyrrolidone (NMP) / methanol. The intrinsic viscosity of PNI-2 was 0.45 dL / g in m-cresol at a concentration of 0.5 g / dL at 30°C.

[0037] Material characterization Fourier transform infrared spectroscopy (FTIR) was performed using a JASCO International FT / IR6600. Elemental analysis was performed using a Heraeus VarioEL-III CHNS elemental analyzer. NMR spectra were measured using a Bruker AVANCE-500 FT-NMR spectrometer with tetramethylsilane as an internal standard, and peak multiplicity is reported below, with s representing single lines and d representing double lines. Intrinsic viscosity was determined at a concentration of 0.5 g / dL using a Tamson TV-2000 viscometer at 30°C. Thermogravimetric analysis (TGA) was performed using a PerkinElmerPyris 1TGA. The experiment was conducted in a nitrogen or air flow at a heating rate of 20°C / min (flow rate = 20 cm³). 3The procedure was performed on film samples of approximately 6-8 mg heated at a rate of 1 / min. Cyclic voltammetry was performed using a PalmSens MultiPalmSens 4 electrochemical analyzer. Electrochemical impedance spectroscopy (EIS) analysis was performed before and after battery cycling using a CH Instruments CHI electrochemical workstation model 760e. The cells were charged and discharged at a constant current using an AcuTech battery station system (AcuTech Systems). Constant current intermittent titration (GITT) was performed using an Admiral Instruments Squitstat potentiostat.

[0038] Electrode preparation and electrochemical measurements The electrodes used in this study were prepared using the slurry method. Briefly, the LiB cathode was prepared by mixing the active material (40 wt%), the conductive carbon SuperP (50 wt%), and PVDF (10 wt%). The anode, on the other hand, was prepared by mixing SuperP (70 wt%) as the conductive carbon and PVDF (10 wt%) with 20 wt% of the active material. Then, both mixtures were dissolved in NMP to form a homogeneous slurry. The slurry was applied onto copper foil (anode) or aluminum foil (cathode) using a doctor blade with a 100 μm clearance. The slurry was then dried on a hot plate at 60°C for 12 hours, followed by a further 8 hours in a vacuum oven at 80°C. The electrodes were cut into 12 mm discs and then moved into a glove box for the cell assembly process. For PNI-1 (represented by formula (I-1) above), PNI-2 (represented by formula (I-2) above), and PNI-3 (represented by formula (I-3) above), the values ​​were 0.62, 0.56, and 0.46 mg / cm³, respectively. -2 The average mass load was obtained. On the other hand, the mass loads of the PNI-1, PNI-2, and PNI-3 anodes were approximately 0.78, 0.61, and 0.70 mg / cm², respectively. -2It was found that... In addition, binder-free cathodes were prepared using the same method, with ratios of active material (40% by weight) and SuperP as conductive carbon (60% by weight), and 0.58 and 0.60 mg / cm³ were used for binder-free PNI-1 and PNI-2, respectively. -2 This resulted in a mass load.

[0039] Finally, a CR2032 type coin cell was assembled in a glove box filled with high-purity argon (H2O < 0.5 ppm and O2 < 0.5 ppm). A lithium foil with a diameter of 12 mm was used as the counter electrode, Celgard 2325 as the separator, and 40 μL of a 1:1 (v / v) ethylene carbonate / diethyl carbonate (EC / DEC) solution of 1 M LiPF6 was used as the electrolyte.

[0040] Regarding electrochemical testing, constant current charge-discharge measurements were performed at the battery testing station (AcuTech Systems) using 1.5~4.5V (Li) for the cathode. + Voltage measurements were performed at 0.02 to 3.0 V for the anode (Li reference) and the surrounding potential window. Cyclic voltammetry (CV) measurements were performed using an electrochemical analyzer (MultiPalmSens4, PalmSens) at 0.1 mVs within the same potential window. -1 The scan speed was as follows: Electrochemical impedance spectroscopy (EIS) analysis was performed before and after the battery cycle using a CH Instruments CHI electrochemical workstation model 760e with a frequency range of 10 mHz to 1 MHz and an AC voltage signal of 10 mV. Constant current intermittent titration (GITT) was performed to investigate ion diffusion in the PNI system. GITT measurements were performed using an Admiral Instruments Squitstat potentiostat with a 50 mAg titration for 20 minutes. -1 The current density was measured by alternating between 10-minute rest intervals. Prior to the GITT measurement, an unused coin cell was subjected to 50mAg -1 It was fully charged and left to rest for up to 10 hours. Then the diffusion coefficient was calculated, where D is the diffusion coefficient (cm 2 s -1) where τ is the current pulse (s), mB is the mass of the host material in the electrode (g), and VM is the molar volume of the material (cm³). 3 mol -1 ) and MB is the molecular weight (gmol) of the host material. -1 ) and S is the contact area (cm²) between the electrolyte and electrode interface. 2 Assuming that ), the following formula

number

[0041] Calculation of diffusion coefficient based on EIS data Electrochemical impedance spectroscopy (EIS) is a powerful tool for investigating electrochemical phenomena occurring in complex electrochemical systems such as battery cells. Generally, a Nyquist plot of an EIS spectrum shows electrochemical processes in three different frequency regions. First, conductivity across the electrolyte, separator, and wiring is reflected in the high-frequency area. Furthermore, the mid-frequency region represents charge transfer and kinetic reactions, while the low-frequency region, usually with a 45-degree slope, represents the diffusion-limited region in the solid phase and is typically characterized by the Warburg impedance. Furthermore, the Warburg impedance is expressed as follows, where Z' and Z'' are the real and imaginary impedances, respectively.

number

number

[0042] Sweep rate voltammetry for charge accumulation properties Sweep rate voltammetry is one of the powerful techniques that can investigate the continuous electrochemical reactions occurring in an electrode. Generally, the total charge in the CV curve is (a) Li + The Faraday contribution can be classified into three components: (b) the Faraday contribution due to the ion diffusion process, (c) the Faraday contribution due to the charge-transfer process with surface atoms, known as pseudocapacitance, and (d) the non-Faraday contribution due to the double-layer effect. Furthermore, the contributions of both types of capacitive effects, such as pseudocapacitance and the double-layer effect, can become more pronounced with increasing electrode surface area. These Faraday contributions from diffusion-controlled and surface-controlled (capacitive effect) processes can be characterized using CV data at various scan speeds, where i is the current response with respect to scan speed v, and a and b are constants, as shown in the following equation: i=av b It can be expressed by the following equation. The b value can be obtained from the slope of logi versus logv. In addition, a b value close to 0.5 indicates a semi-infinite linear diffusion-limited process, while a b value close to 1 indicates that the current is surface-controlled. Since the b value is the sum of the Faraday responses of diffusion-limited and capacitive effects, a detailed examination by sweep rate voltammetry is applied, and the following equation is used: i = k1v + k2v 1 / 2 Due to the capacitance effect (k1v) and diffusion-limited behavior (k2v) 1 / 2 ) can be quantified. The values ​​of k1 and k2 are i / v 1 / 2 vs v 1 / 2 This can be identified by plotting it.

[0043] result Redox properties of TPA-PNI (triphenylamine-based polynaphthalimide) electrodes To investigate the redox properties, cyclic voltammetry (CV) measurements were performed by applying TPA-PNI as both the cathode and anode material of LiB (Figures 1A to 1F). For the cathode, the CV of TPA-PNI was (Li / Li + (For this) With a potential window in the range of 1.5 to 4.5 V, 0.1 mVs -1 The scan is performed at the following speed, while the anode is (Li / Li + The operation was performed within 0.02 to 3.0 V. As shown in Figure 1A, one reduction peak at 2.34 V in the cathode scan of the PNI-1 cathode is observable along with an oxidation peak at 2.47 V in the anode scan. These paired redox peaks are related to the two-electron enolization reaction process of naphthalenediimide (NTDI) units. Furthermore, the oxidation and reduction processes of the triarylamine units, which are radical cations in PNI-1, are observable at 4.21 V and 4.04 V, respectively, and PF6 - This suggests the success of the anion doping / dedoping process. Interestingly, the two well-defined reduction peaks of the NTDI units in PNI-2 were also observed in the cathode scan, at 2.23V and 2.38V (with a difference of approximately 0.15V), along with the oxidation peaks at 2.45V and 2.56V, which may be shifted slightly to the lower voltage side than those of PNI-1 (Figure 1B). This phenomenon may be due to the presence of two cyano groups in PNI-2. The electron-withdrawing properties of cyano groups have been reported to lower the LUMO energy of the polyimide, making it more reducible. Furthermore, PNI-3, a structural isomer of PNI-2, showed slightly higher reduction potentials of NTDI units at 2.26V and 2.43V (with a higher potential difference of approximately 0.17V (Figure 1C)). This suggests that different conformations of cyano groups in the polymer backbone play an important role in tuning the intrinsic properties of TPA-PNI. At higher operating voltages, both PNI-2 and PNI-3 exhibit nearly identical redox pairs at approximately 3.65 / 3.75V and 3.96 / 4.09V (Figures 1B and 1C), where PF6 is present in the two radical nitrogen atoms of the diamine unit. -This can be attributed to anion doping / dedoping processes. The first redox pair at 3.65 / 3.75 V is attributed to the first radical cation reaction during the p-type doping process, while the other redox pairs at higher potentials (3.96 / 4.09 V) are related to the reaction of the second radical cation.

[0044] To further evaluate the TPA-PNI electrodes, we also elucidated their redox properties as anodes (Figures 1D-1F). As shown in Figures 1D-1F, all TPA-PNIs exhibited nearly identical CV curves when applied as LiB anodes. As shown in Figure 1D, for PNI-1, three reduction peaks were observed at potentials of 1.79, 0.84, and 0.02 V, each accompanied by three oxidation peaks at 1.98, 0.93, and 0.14 V. The first redox peak at 1.79 / 1.98 V can be attributed to the redox reaction of carbonyl NTDI units during the lithiation-desilitonation process. On the other hand, the redox process at 0.84 / 0.93 V is attributed to Li on the cyano group. + Caused by insertion / deinsertion. Li relative to carbonaceous units. + Insertion / deinsertion was observed at 0.02 / 0.14 V. Both PNI-2 and PNI-3 exhibited similar CV behavior to PNI-1, but it is important to note that the redox potential associated with the NTDI units was slightly higher than that of PNI-1 (Figures 1E-1F). This behavior may be related to the introduction of two cyano groups with higher charge polarization and electron-withdrawing properties. Furthermore, the redox potential associated with the NTDI units in PNI-3 was also found to be slightly higher than that of PNI-2. This again supports the idea that the position of conformational units modulates the intrinsic electrochemical behavior of TPA-PNI electrodes.

[0045] TPA-PNI cathode battery performance To evaluate the battery performance of the TPA-PNI cathode, we assembled a half-cell LiB, (Li / Li + (For this,) it was charged and discharged with a constant current within a potential window of 1.5 to 4.5V. (Not shown in the diagram) TPA-PNI cathode 50mAg -1The results of the constant current charge and discharge profiles at the current density showed that the PNI-1 cathode reached 125mAhg (after 100 cycles) with a major plateau at 2.47V. -1 This indicates that the specific capacity was as follows. This plateau can be attributed to the enolization and dianion formation of NTDI units. In particular, the plateau attributable to the doping / dedoping process of PNI-1 is hardly seen in the constant current profile. Furthermore, for PNI-2 and PNI-3, three plateaus at 2.27, 3.67, and 3.98 V are observable, indicating the successful formation of lithium enolates and dianions of NTDI units and the doping / dedoping process of nitrogen radical cations in the TPPA portion. Interestingly, PNI-2 and PNI-3 showed almost identical constant current profiles, but PNI-2 showed a difference from that of PNI-3 (170 mAhg -1 ) has a significantly higher storage capacity (195mAhg -1 ) has. This further demonstrates that structural design plays a crucial role in the performance of TPA-PNI.

[0046] Figure 2A shows 50mAg -1 The capacitance profiles of the TPA-PNI cathodes at the current density are shown. As shown in Figure 2A, all TPA-PNI cathodes demonstrated stable cycle performance up to 100 cycles. In particular, the PNI-2 cathode showed 50mAg -1 After 100 cycles, the PNI-1 (125mAhg) had approximately 95% Coulomb efficiency (CE). -1 ) and PNI-3 (170mAhg -1 ) has a higher 195mAh -1 It exhibits a maximum storage capacity of 5000mAg, demonstrating that appropriate structural design significantly enhances the performance of the TPA-PNI cathode. Furthermore, PNI-2 and PNI-3 have a maximum storage capacity of 5000mAg. -1 It demonstrated remarkable rate capabilities up to (Figure 2B). PNI-2 has 100, 500, 1000, 2000 and 5000mAg -1 With current densities of 162, 155, 151, 141, and 124 mAhg respectively. -1 The specific capacity of 170, 153, 145, 134 and 112 mAhg is demonstrated.-1 The specific capacity is 100, 500, 1000, 2000 and 5000 mAg according to PNI-3. -1 It can be obtained at current densities of 100, 500, 1000, 2000 and 5000 mAg. Unlike PNI-2 and PNI-3, the PNI-1 cathode exhibited relatively low rate capability performance. As shown in Figure 2B, the specific capacitance of PNI-1 is obtained at current densities of 100, 500, 1000, 2000 and 5000 mAg. -1 If it changes to 120, 98, 75, 47, and 26 mAhg respectively. -1 It decreased significantly to this extent. Nevertheless, the long-term cycle performance was as follows: all TPA-PNI cathodes were 2000mAg -1 Under high current density, their 130mAhg -1 By maintaining a high capacity up to that point, we demonstrated excellent stability and reversibility (Figure 2C).

[0047] TPA-PNI anode battery performance To investigate the capability of TPA-PNI as a LiB anode, half-cell Li ions were prepared again, (Li / Li + (For this purpose) Charging and discharging were performed with a constant current within a potential window of 0.02 to 3.0V. Although not shown, for all TPA-PNI anodes, two main plateaus occurred at approximately 0.9V and 0.02V, with a charge of 100mAg. -1 This can be observed along with a slight increase in capacity during the cycling process. A similar plateau in this constant current profile is observed for all TPA-PNI anodes with the same Li + It exhibits ion storage characteristics, which are in good agreement with CV tests (Figures 1D-1F). Furthermore, the PNI-1 anode produced 520 mAhg during the first 5 cycles. -1 It exhibits a specific discharge capacity of , and then after 100 cycles, it reaches 650 mAhg -1 It gradually increased to 1100mAhg. Meanwhile, the PNI-2 and PNI-3 anodes also reached 1100mAhg after 100 cycle scans. -1We demonstrated a gradual increase in capacity up to [value]. Consistent with the constant current profile, the increasing specific capacity is clearly illustrated in the profile (Figure 3A). The overall capacity increase during the cycle is due to two parameters: firstly, the increasing Li during the cycle process. + Secondly, it may be related to the fact that it could be allocated to transport; and thirdly, that it may be related to the activation period required for the Li-binding site of TPA-PNI to be completely lithitated.

[0048] Furthermore, the TPA-PNI anode has a 5000mAg -1 It demonstrated excellent rate capability up to (Figure 3B). As shown in Figure 3B, current densities from 100 to 500, 1000, 2000, and 5000 mAg -1 If it changes to these values, the PNI-1 anode will have 611, 508, 460, 408, and 344 mAhg respectively. -1 Reversible capacities were obtained. In good agreement with the capacity profile, PNI-2 was found to have capacities of 100, 500, 1000, 2000 and 5000 mAg. -1 With current densities of 920, 756, 632, 582, and 450 mAhg respectively. -1 It once again demonstrated its maximum specific capacity. Meanwhile, PNI-3 was 100, 500, 1000, 2000 and 5000 mAg -1 With current densities of approximately 760, 605, 490, 410, and 350 mAhg -1 The specific capacitance was observed. The current density was set to 100 mAg. -1 When switched back, PNI-1, PNI-2, and PNI-3 have capacities of 650, 1130, and 970 mAhg respectively. -1 Outstanding rate capability was confirmed by its recoverable specific capacity (Figure 3B). Furthermore, long-term cycle performance was demonstrated by the TPA-PNI anode at 5000mAg. -1 It was shown that it can last up to 2000 cycles under very high current densities (Figure 3C). As shown in Figure 3C, 1000, 1350 and 1375 mAhg -1 The peak capacities were observed in PNI-1 (after 625 cycles), PNI-2 (after 680 cycles), and PNI-3 (after 1250 cycles), respectively.

[0049] Mechanism Research of TPA-PNI Electrodes For the diamine and NTDI units in the TPA-PNI electrode, in order to gain a deeper understanding of the charge storage behavior, sweep rate CV analysis was applied at various scan rates from 0.1 to 1.0 mVs -1 . Figures 4A - 4C show the typical CV curves of the PNI-1, PNI-2, and PNI-3 cathodes at various scan rates, respectively, illustrating the gradual increase in the total current as the scan rate changes from 0.1 to 1.0 V. Further analysis of the total current in various voltage ranges revealed that the b values of the TPA / TPPA and NTDI units in TPA-PNI were in the range of 0.61 - 0.89 (data not shown), indicating that the total charge accumulated in the TPPA and NTDI units was contributed by the synergistic contributions of the diffusion-limiting and surface-controlled (capacitive) processes. The quantitative analysis of the capacitive contribution (k1v) and diffusion contribution (k2v 1 / 2 ) in the TPPA and NTDI units of the TPA-PNI cathode is obtainable from the slope and intercept of the i / v 1 / 2 versus v 1 / 2 plot (data not shown). As shown in Figure 4D, the NTDI unit in PNI-1 (voltage range of 1.7 - 3.0 V) exhibited a capacitive contribution of approximately 70% at the faster scan rates of 1 - 0.5 mVs -1 , and then gradually decreased to 46% at 0.1 mVs -1 . A similar trend was observable in the TPA unit in PNI-1 (voltage range of 4.0 - 4.3 V), showing a gradual decrease in the capacitive contribution from approximately 50% at the faster scan rates of 1 - 0.5 mVs -1 to 34% at the scan rate of 0.1 mVs -1 .

[0050] Interestingly, replacing the diamine unit from TPA to TPPA would significantly adjust the charge storage characteristics of TPA-PNI. As shown in Figures 4E and 4F, adding TPPA units into PNI, such as in PNI-2 and PNI-3, the capacitive contribution to the total charge accumulated in the NTDI unit was approximately 80% at the faster scan rates of 1 - 0.5 mVs -1 , and 0.1 mVs-1 increases significantly to 40% at the lowest scan rate of 1 - 0.5 mVs -1 exhibits almost the same behavior by contributing approximately 80% capacitive at a scan rate of 0.1 mVs -1 and gradually decreases to about 55% at 0.1 mVs (Figures 4E and 4F). This may be brought about by the -C≡N functional groups creating almost the same electronic environment of TPPA. As shown in Figure 4F, the diffusion contribution in the NTDI unit from PNI - 3 increased by approximately 3% compared to that of PNI - 2. The increasing diffusion contribution can also be observed for the TPPA unit (Figure 4E). The diffusion contribution at the potential of 3.3 - 3.9 V in the first radical cation close to the nitrogen atom with two -C≡N functional groups is about 5% more at the faster scan rate of 1 - 0.5 mVs -1 than that of PNI - 2 (Figure 4E), and shows an increase of almost 10% at the lowest scan rate of 0.1 mVs -1 (Figure 4F). On the other hand, the second radical cation in the potential range of 3.9 - 4.3 V (close to the naphthalimide bond) has a higher diffusion contribution of 8% at the scan rate of 1 - 0.5 mVs -1 than that of PNI - 2 (Figure 4E), and 12% at 0.1 mVs -1 (Figure 4F). Here, it is also confirmed that the position of different conformations in the polymer backbone plays an important role in regulating the charge storage behavior.

[0051] Subsequently, EIS measurements were employed to further evaluate the activation energy. The relationship between the exchange current (i0) at various temperatures and the charge transfer resistance (R ct ) at the electrode interface is given by the Arrhenius equations: i0 = RT / nFR a and i0 = Aexp(-E ct where A is a coefficient independent of temperature, R is the gas constant, T(K) is the absolute temperature, n is the number of electrons moving, F is the Faraday constant, and E aIt has been reported that the activation energy can be estimated using R(RT). As shown in Figures 5A-5C, all TPA-PNIs exhibit a single semicircle that gradually shrinks as the temperature increases, and the R(RT) decreases. ct This clearly demonstrates the activation energy (E) of TPA-PNI. a ) is E a = -Rkln10 can be estimated from this, where k is the slope of the fitting line in the Arrhenius plot (Log10i0 as a function of 1000 / T) (Figure 5D). And E of TPA-PNI a For PNI-1, PNI-2, and PNI-3, the concentrations were 14.35, 33.98, and 41.79 kJ / mol, respectively. -1 It was estimated that this was the case. Interestingly, the lowest E was obtained from PNI-1. a This indicates that structures containing TPA units require less energy than others to facilitate charge transfer reactions. In particular, PNI-3 is E a (33.98kJmol -1 ) is higher at 41.79 kJmol -1 E a It was found that it possesses and that more energy is required to activate its charge transfer reaction. The higher E required for PNI-3 a This may also result from higher charge polarization in the molecular structure, which is consistent with the capacity profile in which PNI-3 exhibits slightly lower capacity as both cathode and anode than that of PNI-2. In short, it was found that different molecular structures and conformations play a crucial role in tuning the charge storage behavior and activation energy of TPA-PNI, and therefore further influence their electrochemical performance as LiB electrode materials.

[0052] Battery performance of binder-free PNI electrodes To further verify the multifunctional capabilities of TPA-PNI as both a cathode / anode material and an electrode binder, we conducted battery tests using binder-free cathodes (with an active material to conductive carbon weight ratio of 40:60) for PNI-1 and PNI-2. As shown in Figures 6A and 6B, no significant changes were observed in the CV curves of the binder-free electrodes compared to electrodes containing PVDF binder, indicating well-preserved redox capabilities. Binder-free PNI-1 (Figure 6A) exhibited a reduction peak at 2.35V, along with oxidation at 2.50V, corresponding to the enolization process in NTDI units. Meanwhile, PF6 in TPA... - The doping / dedoping process is observed at 4.23 / 4.03 V. Furthermore, PNI-2 also demonstrates well-retained redox capability by exhibiting its paired redox potentials for the enolization process in NTDI and the doping / dedoping process in TPPA (Figure 6B). In addition, the constant current profiles of the binder-free cathode (data not shown) showed good agreement with their CV results. Although not shown, two plateaus at 2.47 and 2.34 V can also be observed for binder-free PNI-1, which may be attributed to the enolization process of the NTDI unit. However, plateaus related to the doping / dedoping process originating from TPA are difficult to observe in the constant current profiles. Furthermore, binder-free PNI-2 exhibits four plateaus at 2.27, 2.41, 3.67, and 3.98 V, indicating the successful formation of lithium enolates and dianions of NTDI units and the doping / dedoping process of TPPA.

[0053] Furthermore, binder-free PNI-1 and PNI-2 50mAg -1 The cycle performance (Figure 6C) showed a specific capacitance equivalent to that of the binder-containing version (Figure 2A). As shown in Figure 6C, the cathodes of binder-free PNI-1 and PNI-2 were 50 mAg. -1 160 and 202mAhg -1It exhibited stable cycle performance up to 100 cycles with a specific capacitance. This specific capacitance was even higher than that of their respective electrodes with a PVDF binder (Figure 2A). To elucidate this phenomenon, EIS measurements were again applied to understand the transport characteristics in the binder-free cathode. Although not shown, a significant reduction in the semicircle can be observed in both binder-free PNI-1 and PNI-2 after cycling. This shrinking semicircle is due to a significant decrease in R of the binder-free cathode, from 222.03 to 119 Ω for PNI-1 and from 313.96 to 57.64 Ω for PNI-2. ct In relation to this, it shows better transport capacity after the cycle. In particular, the DLi of binder-free cathodes + The higher values ​​compared to those with a PVDF binder may be due to the formation of a homogeneous slurry even without a PVDF binder, and the higher conductor content of the binder-free cathode (60% SuperP) compared to those with a binder (50% SuperP), thereby significantly improving transport characteristics and storage capacity.

[0054] In addition to its excellent capacity, both the binder-free PNI-1 and PNI-2 cathodes offer 5000mAg -1 It also exhibited excellent rate capability at current densities up to 100 mAg (Figure 6D). Excellent rate performance was achieved at current densities up to 100 mAg. -1 137mAhg that can be recovered when returning to its original state -1 (Binder-free PNI-1) and 152mAhg -1 This is confirmed by the maximum storage capacity of the binder-free PNI-2. Furthermore, both the cathodes of the binder-free PNI-1 and PNI-2 have a capacity of 2000mAhg. -1It showed particularly excellent long-term cycle stability up to 5000 cycles under high current densities (Figure 6E). As shown in Figure 6E, the long-term cycle capability is confirmed by maintaining capacity retention rates higher than 45% and 75% for binder-free PNI-1 and PNI-2, respectively. The electrochemical performance further suggests that TPA-PNI can act simultaneously as a multifunctional component in LiB, both as an active material and a binder.

[0055] This invention provides polynaphthalimide (TPA-PNI) prepared from triphenylamine diamine monomers, which are further fabricated as battery electrode materials. The triphenylamine skeleton is selected to be incorporated into the polymer backbone, providing more accessible active sites and enabling efficient electron transfer during electrochemical processes. Nitrogen radicals in the triphenylamine structure are PF6 - The anions can actively participate in electrochemical redox processes in which they can be reversibly doped and dedoped, and therefore the operating voltage was increased to 4.2V.

[0056] In addition, we demonstrated the efficient storage capacity of a novel triphenylamine-based polynaphthalimide (TPA-PNI) that can simultaneously act as both the cathode and anode for lithium-ion batteries. By leveraging the high capacity and low solubility of naphthalimide, the hybrid TPA-PNI exhibited outstanding electrochemical performance and operational durability. As a cathode, the TPA-PNI cathode achieved 50 mAg after 100 cycles. -1 195mAhg -1 It was able to achieve a high specific capacity up to 1092mAhg. -1 The maximum capacity is 100mAg after 100 cycles. -1 It can be stored in the TPA-PNI anode. In addition, the binder-free TPA-PNI cathode can store 50mAg after 100 cycles. -1 Approximately 202mAhg -1 It demonstrated stable cycle performance with its maximum capacity. Furthermore, the TPA-PNI electrode had a capacity retention rate of over 75% and 2000mAg-1 Good cycle stability over 5000 cycles under high current density and 5000mAg -1 It also demonstrated excellent rate capability up to a certain point. Mechanistic studies revealed that the outstanding electrochemical performance of TPA-PNI is largely related to appropriate structural design, and the resulting precisely tuned activation energy, charge storage behavior, and cycle stability.

[0057] While this disclosure has been described in relation to its embodiments, it should be understood that numerous other possible modifications and variations may be made without departing from the spirit and scope of this disclosure as claimed below.

Claims

1. The following equation (I) 【Chemistry 1】 A polynaphthalimide having repeating units represented by, A is a polynaphthalimide, which is a cyanosubstituted arylamine moiety.

2. A is given by the following equation (II) 【Chemistry 2】 It is represented by and X is combined or 【Transformation 3】 And Y is combined or 【Chemistry 4】 The polynaphthalimide according to claim 1, wherein N in X or Y is not bound to N in formula (II).

3. A is given by the following equation (II-1) 【Transformation 5】 It is represented by and X is combined or 【Transformation 6】 And Y is combined or 【Transformation 7】 The polynaphthalimide according to claim 1, wherein N in X or Y is not bound to N in formula (II-1).

4. The aforementioned repeating units are given by the following formulas (I-1), (I-2), and (I-3): 【Transformation 8】 The polynaphthalimide according to claim 1, which is any one represented by

5. Current collector and, Displaced on the current collector, an electrode material comprising the polynaphthalimide described in claim 1, An electrode equipped with the following features.

6. The electrode according to claim 5, which is a cathode.

7. The electrode according to claim 5, which is an anode.

8. The electrode material is Active material and, Conductive carbon and, Binder and, further including, The average mass load of the aforementioned polynaphthalimide is 0.2 mg / cm³. ２ ~1.0 mg / cm ２ The electrode according to claim 5, which is within the range.

9. The electrode according to claim 8, wherein, based on the total weight of the electrode material, the content of the active material is 20% to 60% by weight, the content of the conductive carbon is 30% to 70% by weight, and the content of the binder is 2% to 15% by weight.

10. The electrode material is Active material and, Conductive carbon and, It further includes, The average mass load of the aforementioned polynaphthalimide is 0.2 mg / cm³. ２ ~1.0 mg / cm ２ The electrode according to claim 5, wherein the electrode material is within the specified range and no other binders are present in the electrode material.

11. The electrode according to claim 10, wherein, based on the total weight of the electrode material, the content of the active material is 20% to 70% by weight, and the content of the conductive carbon is 30% to 80% by weight.

12. An electrode comprising a current collector and an electrode material containing polynaphthalimide as described in claim 1, A counter electrode positioned opposite the aforementioned electrode, An electrolyte disposed between the electrode and the counter electrode, A lithium-ion battery equipped with these features.

13. The lithium-ion battery according to claim 12, wherein the electrode is a cathode.

14. The lithium-ion battery according to claim 12, wherein the electrode is an anode.

15. The lithium-ion battery according to claim 12, wherein the electrolyte comprises a lithium salt.

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