High voltage, high power battery with dual redox center ferrocene organic positive electrode

Abstract

The present invention provides a high voltage, high power battery capable of efficiently storing and transferring energy wherein the battery comprises at least one negative electrode made of lithium metal or zinc metal and an organic positive electrode having an active material wherein the active material is (ferrocenyl methyl) trimethyl ammonium iodide (FcNI), the invention relates to a compound taking ferrocene as a framework and introducing a methyl trimethyl ammonium iodide group, which has the structure of the following chemical formula (1): the battery also comprises at least one porous polymer diaphragm, the porosity range of the porous polymer diaphragm is about 30%-90%, and ion transmission is facilitated while the structural integrity is maintained. In addition, the battery also comprises an ether electrolyte, so that the optimal electrochemical performance can be realized. What is worthy of attention is that the introduced methyl trimethyl ammonium iodide group can enhance the redox activity of Fe < 3 + > / 2 < + > and is used as an active double redox center to support multi-electron transfer. More particularly, the electron energy of the oxidation-reduction potential of iron can be adjusted by introducing the group, so that the discharge platform of Fe < 3 + > / 2 < + > is increased by about 0.8 V.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of battery materials, and more particularly, to a high-voltage, high-power battery with an organic cathode having a ferrocene with dual redox centers. BACKGROUND

[0002] Due to the increasing demand for large-scale battery systems and smart renewable energy grids, the development of advanced battery technologies is highlighted. Compared to inorganic metal oxides, organic electrode materials are of great interest due to their easy availability, low environmental impact, and higher ability to scale up production. By molecular-level engineering, unique structures of organic compounds can be synthesized and designed to have superior energy storage capacity as electrodes.

[0003] However, current battery development faces some limitations and challenges, such as how to introduce high electron density redox pairs into stable materials, which is very important for achieving high-voltage output and fast charge transfer. In general, organic cathode materials have low redox activity, limited number of electron transfer, and low redox potential (Fermi energy) themselves, so their capacitance is low (mostly less than 200 mAh g -1 , and only at low rates), and the discharge voltage is low (mostly less than 1 V, relative to Zn / Zn 2+ ), resulting in low energy density of the battery made. In addition, organic electrodes also face the problem of poor dynamic performance, which can be mainly attributed to slow redox kinetics and low conductivity.

[0004] Ferrocene (Fe(C5H5)2) is an organic material that has attracted much attention, which belongs to a metal-organic compound and won the Nobel Prize in 1973. Its feature lies in the key role it plays in the chemistry of organic metal sandwich compounds. Ferrocene is composed of a central iron atom combined with two cyclopentadienyl ligands. Due to the high abundance and low cost of iron, ferrocene and its derivatives have attracted widespread attention in the field, and unlike traditional p-type, n-type and bipolar organic cathode materials, ferrocene relies on a reversible F 3+ / 2+ redox process. Currently, it is soluble in electrolyte as a cathode electrolyte in flow batteries, but still faces major challenges for application in traditional static batteries.

[0005] The unsatisfactory redox potential of ferrocene (only 0.4 V relative to the standard hydrogen electrode) and low capacity (theoretical value of 144 mAh g -1), making it difficult to be used in positive electrode materials. These limitations are mainly due to its limited electron transfer ability and its own low redox potential (Fermi energy); in addition, the thermodynamic instability of ferrocene also causes it to sublime at room temperature. These are not suitable for traditional positive electrode preparation methods, and the process is forced to add stabilizers, further limiting its capacity. Although some adjustability can be achieved through molecular modification, the modified molecules are still limited in terms of activity improvement, and are usually accompanied by an increase in molecular weight and the risk of further reducing the already unsatisfactory redox potential. Therefore, current research on the application of ferrocene-based molecules as electroactive materials in batteries is limited, and most of them have ended in failure.

[0006] In view of the above problems, the present invention provides an electroactive ferrocenyl molecule with high activity, multiple redox active sites and high voltage output, aiming to address the urgent demand for efficient and practical ferrocenyl materials in battery applications. Summary of the Invention

[0007] The object of the present invention is to provide a device, material or method to solve the above technical problems.

[0008] According to a first aspect of the present invention, a high-voltage, high-power battery is provided. More specifically, the battery comprises: at least one negative electrode comprising one or more materials selected from lithium metal or zinc metal; At least one organic positive electrode having an active ingredient, the active ingredient being (ferrocenylmethyl)trimethylammonium iodide (FcNI), whose molecular formula is (1): at least one porous polymer separator having a porosity of about 30% to about 90%; and Ether electrolytes.

[0009] According to one embodiment of the present invention, the (ferrocenylmethyl)trimethylammonium iodide is ferrocene having a methyltrimethylammonium iodide group.

[0010] According to one embodiment of the present invention, the methyltrimethylammonium iodide group can enhance the Fe 3+ / 2+ The redox activity of I 0 / - Acts as an active redox center for multi-electron transfer.

[0011] It is noteworthy that the electron energy associated with the iron redox potential can be tuned by introducing methyltrimethylammonium iodide groups to significantly increase the Fe 3+ / 2+ The discharge platform is increased by about 0.5 to 1.0V.

[0012] According to one embodiment of the present application, when the negative material is lithium metal, the maximum operating voltage of the battery can reach 3.5V.

[0013] According to one embodiment of the present application, when the negative material is zinc metal, the maximum operating voltage of the battery is 1.7V.

[0014] According to one embodiment of the present application, the organic preparation method comprises: mixing (ferrocenylmethyl) trimethylammonium iodide, conductive particles and a binder in a solvent to obtain a mixture; and coating the mixture on a current collector and drying in a vacuum oven at 40-70°C for at least 24 hours.

[0015] According to one embodiment of the present application, the current collector is selected from carbon cloth, carbon paper, graphite paper, titanium foil / titanium mesh or high-voltage high-valence iodized stainless steel.

[0016] According to one embodiment of the present application, the solvent is selected from monoethylene glycol ether, diethylene glycol ether, triethylene glycol ether or tetraethylene glycol ether.

[0017] According to one embodiment of the present application, the conductive particles are selected from reduced graphene oxide, activated carbon, hollow carbon spheres or carbon cloth.

[0018] According to one embodiment of the present application, the binder is selected from styrene-butadiene rubber (SBR) or polyvinylidene fluoride (PVDF).

[0019] According to one embodiment of the present application, the ether-based electrolyte is an ether-based solvent with or without additives, the ether-based solvent being selected from monoethylene glycol ether, diethylene glycol ether, triethylene glycol ether, tetraethylene glycol ether or any combination thereof in a volume ratio of 1:1, 1:2, 1:3 or 1:4.

[0020] According to one embodiment of the present application, the additives are selected from saccharin, vanillin, sorbitol or aromatic analogues.

[0021] According to one embodiment of the present application, when the negative material is zinc metal, the additives include C=O, -F, -O- or -SO3 groups; when the negative material is lithium metal, the additives include lithium fluoride, lithium nitrate, vinylene carbonate (VC), vinylene carbonate, allyl vinyl carbonate or lithium bis(fluorosuborate) oxalate (LiDFOB).

[0022] According to one embodiment of the present application, the ether-based electrolyte includes zinc or lithium salts.

[0023] According to one embodiment of the present invention, the zinc salt is selected from zinc bis(trifluoromethanesulfonyl)imide (Zn(TFSI)2), zinc bis(fluorosulfonylimide) (Zn(FSI)2), zinc trifluoromethanesulfonate (Zn(OTF)2), zinc perchlorate (Zn(C1O4)2), zinc acetate (ZnAc2), zinc chloride (ZnCl2) or zinc hexafluorophosphate (Zn(PF6)2).

[0024] According to one embodiment of the present invention, the lithium salt is selected from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiOTF), lithium hexafluorophosphate (LiPF6), lithium perchlorate (LiClO4), lithium tetrafluoroborate (LiBF4), lithium hexafluoroarsenate (LiAsF6) or lithium bis(fluoroborate) oxalate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings, in which:

[0026] Figures 1A-1G The synthesis design and properties of (ferrocenylmethyl)trimethylammonium iodide are shown, wherein Figure 1A The synthesis process of (ferrocenylmethyl)trimethylammonium iodide is schematically shown. Figure 1B (ferrocenylmethyl)trimethylammonium iodide 1 H NMR spectroscopy, Figure 1C The molecular structure of (ferrocenylmethyl)trimethylammonium iodide is schematically shown. Figure 1D Density functional theory calculated values ​​of the lowest unoccupied molecular orbital and highest occupied molecular orbital of (ferrocenylmethyl)trimethylammonium iodide, ferrocene, and iodine are shown. Figure 1E shows the Gibbs free energy calculated by density functional theory, Figure 1F showing the optimized charge density difference, and Figure 1G Display predicted reaction pathways;

[0027] Figures 2A-2D Shows the properties of (ferrocenylmethyl)trimethylammonium iodide, where Figure 2A This is a scanning electron microscope image of (ferrocenylmethyl)trimethylammonium iodide. Figure 2B Display the energy dispersion spectrum imaging analysis results, Figure 2C shows the Fourier transform infrared spectrum of (ferrocenylmethyl)trimethylammonium iodide, and Figure 2D Shows the UV-visible absorption results of (ferrocenylmethyl)trimethylammonium iodide;

[0028] Figures 3A-3B (ferrocenylmethyl)trimethylammonium iodide ( Figure 3A ) and ferrocene ( Figure 3B ) 1H NMR spectrum in dimethyl sulfoxide (DMSO);

[0029] Figure 4 shows the electrostatic potential analysis of (ferrocenylmethyl)trimethylammonium iodide;

[0030] Figures 5A-5G shows the voltage enhancement and redox mechanism of (ferrocenylmethyl)trimethylammonium iodide observed by in-situ Raman spectroscopy and ex-situ X-ray photoelectron spectroscopy, wherein Figure 5A shows the cyclic voltammograms (scan rate of 2 mV / s) of ferrocene, iodine and (ferrocenylmethyl)trimethylammonium iodide with zinc negative electrode and their chemical structures, Figure 5B is a voltage profile showing two discharge plateaus and voltage enhancement can be observed, Figure 5C is a schematic diagram showing the electronic density of states of the cathode and its Fermi level (EFA is the Fermi level of the negative electrode, SEI represents the solid electrolyte interface), Figure 5D shows the galvanostatic charge-discharge curves of zinc-(ferrocenylmethyl)trimethylammonium iodide battery at different current densities, -1 Figure 5E shows the change of I3 - band, Figure 5F shows the ex-situ obtained iodine 3d spectra at different states of charge, and Figure 5G shows the ex-situ obtained iron 2p spectra at different states of charge;

[0031] Figures 6A-6C shows the X-ray photoelectron spectroscopy results of (ferrocenylmethyl)trimethylammonium iodide at the discharge state of 0.6 V Figure 6A ), 1.3 V Figure 6B ) and 2.0 V Figure 6C ), respectively;

[0032] Figures 7A-7G shows the performance of zinc-(ferrocenylmethyl)trimethylammonium iodide battery and its comparative data, wherein Figure 7A is the galvanostatic charge-discharge curves of zinc-(ferrocenylmethyl)trimethylammonium iodide full cell at different current densities; Figure 7B shows the discharge capacity at different rates; Figure 7C shows the capacity contribution of each discharge plateau at different charge-discharge rates; Figure 7D shows the specific capacity of different charge-discharge rates at each plateau; Figure 7E shows the cycle performance and coulombic efficiency when the current density is 5 A g -1 ; Figure 7F shows the voltage profile of the battery in the last 10 cycles within 5000 cycles (the double plateau remains unchanged throughout the cycle); Figure 7G ​Comparing the gravimetric energy density, voltage and cycle number of zinc- (ferrocenylmethyl) trimethylammonium iodide batteries (star shape, based on active center mass or total mass) with commercially available organic cathodes (circle shape), manganese oxides (rectangle shape), Prussian blue analogues (triangle shape), vanadium-based materials (inverted triangle shape), Chevrel phase Mo6S8 (hexagon shape) batteries;

[0033] Figures 8A-8E Showing the performance of lithium- (ferrocenylmethyl) trimethylammonium iodide full cells, where Figure 8A Showing the cyclic voltammetry (CV) curves of lithium- (ferrocenylmethyl) trimethylammonium iodide full cells at scan rates of 0.2 to 0.5 mV / s (upper half) and 2 to 10 mV / s (lower half); Figure 8B Constant current charge-discharge curves of lithium- (ferrocenylmethyl) trimethylammonium iodide full cells at different current densities; Figure 8C Showing the operating voltage and crust content comparison of various conversion-type cathodes suitable for lithium batteries; Figure 8D Showing the discharge capacity at different rates; and Figure 8E Showing the long-term cycle performance at 1 A g -1 ;

[0034] Figure 9 Showing the correlation of energy density and power density of organic batteries zinc- (ferrocenylmethyl) trimethylammonium iodide batteries and lithium- (ferrocenylmethyl) trimethylammonium iodide batteries;

[0035] Figures 10A-10B Showing the cyclic voltammetry curves of zinc- (ferrocenylmethyl) trimethylammonium iodide and lithium- (ferrocenylmethyl) trimethylammonium iodide batteries at scan rates of 0.2-0.5 mV s -1 (upper half), 2-10 mV s -1 (middle part) and 20-50 mV s -1 (lower half), where Figure 10A is the zinc- (ferrocenylmethyl) trimethylammonium iodide battery, Figure 10B is the lithium- (ferrocenylmethyl) trimethylammonium iodide battery;

[0036] Figures 11A-11F Showing the characteristics of (ferrocenylmethyl) trimethylammonium iodide fast kinetics, where Figure 11A and Figure 11B show the relationship between the peak current log value of the cathode and anode current and the scan rate log value when iodine redox and iron redox in zinc- (ferrocenylmethyl) trimethylammonium iodide Figure 11A and lithium- (ferrocenylmethyl) trimethylammonium iodide batteries Figure 11B , respectively; Figure 11C and Figure 11DZinc-(ferrocenylmethyl)trimethylammonium iodide (Zn-FCM-TMAI) and lithium-(ferrocenylmethyl)trimethylammonium iodide (Li-FCM-TMAI) batteries, respectively, showing the capacity contribution at different scan rates; Figure 11C showing the capacity contribution at different scan rates; Figure 11D showing the AC impedance spectra (right side: corresponding equivalent circuit model); Figure 11E showing the relaxation time distribution at different voltages, with the inset showing a local zoom-in at short relaxation times; and Figure 11F

[0037] Figure 12 showing the relaxation time distribution at different voltages (10 -6 s < τ < 10 s).DETAILED DESCRIPTION

[0038] In the following description, high-voltage, high-power batteries and related embodiments are presented as preferred embodiments. It will be apparent to those skilled in the art that modifications, including additions and / or substitutions, can be made without departing from the scope and spirit of the present disclosure. In the following description, specific details are set forth in order to provide a thorough understanding of the present disclosure. However, one skilled in the relevant art will recognize that the application can be practiced without one or more of the specific details, or with other methods, components, materials, and so forth.

[0039] The term "active material of an electrode" refers to a material that directly participates in the electrode reaction (including the charging and discharging reactions) and plays a primary function in the battery system.

[0040] As used herein, "anode" refers to the electrode into which charge flows into a polarized power device. From an electrochemical perspective, negatively charged anions typically move toward the anode, and / or positively charged cations flow out of the anode to balance the electrons flowing in from the external circuit, while in a discharging battery, the anode is the negative electrode from which electrons flow out. If the anode is composed of a metal, it is accompanied by the phenomenon of metal cations being released from the electrode into the electrolyte while it releases electrons to the external circuit.

[0041] As used herein, "organic cathode" refers to the electrode from which charge flows out of a power device. From an electrochemical perspective, in a battery or other polarized power device, positively charged cations typically move toward the organic cathode, and negatively charged anions flow out of the cathode to maintain charge balance as electrons pass through the external circuit. In a discharging battery, the organic cathode is the positive electrode, consistent with conventional current flow direction, and this outflow of charge is accompanied by the movement of positive ions from the electrolyte into the organic cathode to participate in the overall electrochemical processes occurring within the device.

[0042] According to a first aspect of the present disclosure, a high-voltage, high-power battery is provided that optimizes energy storage efficiency and overall performance.

[0043] ​The battery includes at least one anode composed of lithium metal or zinc metal, and at least one organic cathode containing an active material, wherein the active material is (ferrocenylmethyl)trimethylammonium iodide (FcNI). The battery has excellent power output and voltage stability. The (ferrocenylmethyl)trimethylammonium iodide compound has a unique ferrocene skeleton and a methyltrimethylammonium iodide group, which can act as a high-efficiency redox mediator in the cathode to promote multi-electron transfer and enhance the redox activity of Fe 3+ / 2+ , and effectively adjust the electron energy related to the redox potential of iron, increasing the discharge plateau of Fe 3+ / 2+ about 0.5-1.0V. In addition, the battery contains a porous polymer separator with a porosity of about 30%-90% to ensure efficient ion transfer between the anode and the cathode, and an ether-based electrolyte to improve ion conductivity and overall battery performance. Notably, the compound conforms to the following formula (1):

[0044] In some embodiments, when the anode material is lithium metal, the battery can achieve a maximum operating voltage of 3.5V; when the anode material is zinc metal, the maximum operating voltage is 1.7V, showing the adaptability and flexibility of the cathode in different metal anodes.

[0045] The preparation process of the organic cathode includes mixing (ferrocenylmethyl)trimethylammonium iodide with conductive particles and a binder in a solvent to obtain a mixture, then coating the mixture on a current collector, and drying in a vacuum oven at 40-70°C. The options for the current collector include carbon cloth, carbon paper, graphite paper, titanium foil / net or high-valence chlorinated stainless steel to ensure compatibility with various battery configurations; the solvent options include mono-, di-, tri-, or tetraglyme; the conductive particles can be reduced graphene oxide, activated carbon, hollow carbon spheres, or carbon cloth; and the binder can be styrene-butadiene rubber or polyvinylidene fluoride to further enhance the stability and adhesion of the cathode material.

[0046] The ether-based electrolyte (including ether-based solvent with or without additives) is important for the overall performance and safety of the battery. The ether-based solvent can be selected from mono-, di-, tri-, or tetra-glyme, and can be used in different volume ratios. The additives can be selected from saccharin, vanillin, sorbitol, or aromatic compounds to provide additional stability and ionic conductivity. Depending on the composition of the anode material, specific additives can be selected to optimize the performance and lifetime of the battery. For zinc-based anodes, additives containing C=0, -F, -0-, or -SO3groups can be used. For lithium-based anodes, additives such as lithium fluoride, lithium nitrate, vinylene carbonate, ethylene carbonate, allyl ethyl carbonate, or lithium bis-oxalato-borate can be used. In addition, the ether-based electrolyte can also contain zinc / lithium salts such as zinc bis(trifluoromethanesulfonyl)imide, zinc bis(fluorosulfonyl)imide, zinc triflate, zinc perchlorate, zinc acetate, zinc chloride, or zinc hexafluorophosphate, lithium bis-trifluoromethanesulfonyl imide, lithium triflate, lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, or lithium bis(fluoroborate)oxalate to further enhance the performance and stability of the battery.

[0047] As shown in Figure 1A , the synthesis of (ferrocenylmethyl)trimethylammonium iodide is as follows: ferrocene is subjected to an aminomethylation reaction to form (ferrocenylmethyl)dimethylamine. Subsequently, (ferrocenylmethyl)dimethylamine is subjected to an alkylation treatment with iodomethane to form (ferrocenylmethyl)trimethylammonium iodide.

[0048] In one embodiment, bis(dimethylamino)methane is added dropwise to a mixed solution of glacial acetic acid and phosphoric acid, the reaction temperature is maintained at 0°C, and the operation is carried out under nitrogen protection; then the reaction mixture is heated to room temperature, stirred under reflux conditions for 5 hours after the addition of ferrocene; after the reaction, dilution with water and separation of the organic phase with ethyl acetate, the organic phase is extracted with 1M hydrochloric acid, and the aqueous phase is adjusted to pH 10-12 with 4M sodium hydroxide and extracted twice with ethyl acetate; after washing the combined organic phase with saturated brine, drying with anhydrous sodium sulfate, and finally removing the solvent under reduced pressure, (ferrocenylmethyl)dimethylamine is obtained as an orange oil after column chromatography purification (mobile phase: 2% methanol, 5% triethylamine in ethyl acetate).

[0049] (ferrocenylmethyl)dimethylamine is dissolved in 5mL of diethyl ether, and iodomethane is added dropwise thereto while maintaining the reaction temperature at room temperature; after stirring for 2 hours, the orange precipitate is filtered and washed twice with 20mL of diethyl ether; finally, after drying under vacuum, (ferrocenylmethyl)trimethylammonium iodide is obtained as a yellow powder.

[0050] (ferrocenylmethyl)trimethylammonium iodide is a yellow powder, and the scanning electron microscope image Figure 2A and Figure 2B) observation, it is a flaky solid structure with a smooth surface. Further, the Fourier transform infrared spectrum and ultraviolet-visible absorption spectrum (see Figure 2C and Figure 2D ) detect the characteristic absorption peak of (ferrocenylmethyl) trimethylammonium iodide, highlighting its unique properties. It is worth noting that the introduction of the methyl trimethylammonium iodide group not only activates the redox site of Fe 2+ , but also has iodine ions bound by ionic bonds, giving (ferrocenylmethyl) trimethylammonium iodide the properties of a multi-electron active center, thus achieving high specific capacity.

[0051] The molecular structure of (ferrocenylmethyl) trimethylammonium iodide was further analyzed using 1 H nuclear magnetic resonance spectroscopy, and the results showed that it has four different types of protons (the ratio of A:B:C:D is 5:4:2:9), consistent with the molecular structure in Figure 1B ; in addition, thermogravimetric analysis showed that (ferrocenylmethyl) trimethylammonium iodide has high thermal stability, with an initial weight loss temperature of more than 200°C (as shown in Figure 3A ), while ferrocene decomposes at less than 80°C (see Figure 3B ), indicating that the side chain has a significant effect on the electronic structure of ferrocene. Figure 1C The molecular structure of (ferrocenylmethyl) trimethylammonium iodide with dual active centers (iron and iodine) and the interaction between active sites is further shown in

[0052] The following will further detail the detection and results of electrochemical tests on batteries and / or electrodes.

[0053] In short, CR2032 type button batteries were used for electrochemical testing, with a separator membrane composed of a three-layer structure of polypropylene / polyethylene / polypropylene (Celgard 2325). The charge-discharge curve was detected and recorded using a LAND CT2001A battery testing instrument; while the data related to cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were tested using a CHI 760E multi-channel electrochemical testing instrument; the specific energy density (E) of the full battery was calculated according to the following formula: E Wh kg -1 =∫Vv dCmAh g -1

[0054] In the kinetic analysis, the relationship between current i and scan rate v is: i=a v b

[0055] When the b value is 0.5, the current is controlled by semi-infinite diffusion, and when the b value is 1, the current has capacitive behavior. However, when the b value is between 0.5 and 1, the current is controlled by a mixture of diffusion and capacitance. The current response i is a combination of capacitor-like and diffusion-controlled behavior, as described by the following equation:

[0056] By determining k1 and k2, the current fractions contributed by the diffusion-controlled intercalation process and the capacitive process, respectively, can be calculated based on the potential.

[0057] In order to evaluate the redox properties of (ferrocenylmethyl)trimethylammonium iodide, the energy levels of its lowest unoccupied molecular orbital and highest occupied molecular orbital were calculated by first-principles density functional theory. Briefly, the relevant calculations were performed using the Cambridge Sequential Total Energy Package (CASTEP) code of Materials Studio software based on density functional theory, and the generalized gradient approximation of the Perdew-Burke-Ernzerhof (PBE) functional was used to describe the electron exchange and related effects, in which the kinetic energy cutoff was set to 500 eV, and the geometry optimization in the conjugate gradient method was performed with a force on each atom less than In addition, the convergence thresholds of energy and force are set to 10 -5 eV and The Brillouin zone is sampled with a 1x1x1 k-point grid, and the Gibbs free energy change (ΔG) of the intermediate is calculated to predict the reaction path. The calculation formula for ΔG is: ΔG=E(gse)+E(zpe)-TΔS Among them, E(gse) is the ground state energy, E(zpe) is the zero-point energy, and TΔS is the entropy term (temperature multiplied by entropy change). The latter two terms can be obtained by calculating the vibration frequency through density functional theory.

[0058] The T value is set to 298.15 K. The free energy (ΔG) of different products is also defined as: ΔG = E(product) - E(reactant) where E(products) is the energy of the products in each step and E(reactants) is the total energy of the reactant (ferrocenylmethyl)trimethylammonium iodide in its oxidized state.

[0059] like Figure 1DAs shown, the lowest unoccupied molecular orbital (-1.83 eV) of (ferrocenylmethyl)trimethylammonium iodide is lower than that of ferrocene (-1.43 eV), i.e., (ferrocenylmethyl)trimethylammonium iodide has a higher electron affinity and a stronger reduction potential than ferrocene. In addition, the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy level is significantly reduced, with the energy gap of (ferrocenylmethyl)trimethylammonium iodide (2.06 eV) being lower than that of ferrocene (2.84 eV), showing that the self-electronic conductivity of (ferrocenylmethyl)trimethylammonium iodide is superior to that of ferrocene. The Gibbs free energy (ΔG) calculation results of the two-electron transfer process are as shown in Table 1. Figure 1E As shown, the reaction path is explained from a thermodynamic point of view: the initial step can involve the reduction of Fe 3+ or I 0 , but since the ΔG value of Fe 3+ is large (-6.62 eV), it is more likely to involve the reduction of Fe 3+ , wherein it is noted that the reduction ΔG of Fe 3+ in (ferrocenylmethyl)trimethylammonium iodide is also greater than that of ferrocene (-5.77 eV), showing that the reduction potential will be shifted, since the potential is directly related to ΔG; subsequently, the reduction ΔG value from I 0 to I - can be significantly observed (-4.64 eV), showing a unique second reduction platform in the discharge process, and the change in electronic properties after the substituent effect is also highlighted by the equilibrium electrostatic potential of (ferrocenylmethyl)trimethylammonium iodide (as shown in Figure 1F and Figure 4 ). Based on the above analysis, Figure 1G the structural evolution of (ferrocenylmethyl)trimethylammonium iodide in the discharge process is predicted in the form of a schematic diagram, i.e., the initial step can involve the reduction of Fe 3+ on the cyclopentadienyl ring to Fe 2+ , followed by the reduction of 1 0 on the organic group.

[0060] In order to analyze the electrochemical properties (multiple redox reactions and significantly improved voltage) of (ferrocenylmethyl)trimethylammonium iodide, further detection will be carried out with a zinc battery as a model system.

[0061] In one embodiment, a (ferrocenylmethyl)trimethylammonium iodide positive electrode was prepared as follows: (ferrocenylmethyl)trimethylammonium iodide powder, Ketjen black (KB), and polyvinylidene fluoride were mixed in an N-methylpyrrolidone (NMP) solvent at a mass ratio of 7:2:1 and stirred vigorously for 20 minutes. The slurry was then coated on a flexible carbon cloth and dried in a vacuum oven at 50°C for 24 hours to produce the positive electrode. In a zinc battery model, zinc foil was used as the negative electrode, and a 1M lithium / zinc salt (ZnTFSI) solution in ethylene glycol dimethyl ether (DME) served as the electrolyte.

[0062] Iodine and ferrocene electrodes were also prepared as comparison groups. The preparation process is briefly described: First, supercapacitor activated carbon powder YP50 powder, Ketjen black, and polyvinylidene fluoride are mixed in an N-methylpyrrolidone solvent at a mass ratio of 5:2:1 and stirred vigorously for 20 minutes to obtain a slurry. The slurry is then coated on titanium foil and dried in a vacuum oven at 70°C for 24 hours to form YP50 discs. The YP50 discs are then placed in a stainless steel reactor along with iodine or ferrocene, sealed, and heated to 70°C for 12 hours. The iodine or ferrocene loading (approximately 50 wt%) is calculated by subtracting the mass of pure YP50 from the total mass of iodine-containing YP50.

[0063] like Figure 5A As shown in the cyclic voltammetry curve of (ferrocenylmethyl)trimethylammonium iodide recorded by CHI 760E multi-channel electrochemical detection instrument, two pairs of peaks at about 1.2V and 1.7V (relative to Zn) can be observed. 2+ First, compared with the cathode peak of ferrocene (0.9 V) and the cathode peak of iodine (1.15 V), (ferrocenylmethyl) trimethylammonium iodide has an activated Fe 3+ / 2+ The redox couple, therefore, has a significant increase in discharge voltage (increased by 0.8V). In addition, compared with iodine, the I 0 / - The redox polarization also decreased by 0.05 V. Secondly, Fe 3+ / 2+ The redox activity of zinc-(ferrocenylmethyl)trimethylammonium iodide battery is significantly enhanced, especially in the cyclic voltammetry curve, where a large peak appears at 1.7V, while the corresponding peak in the cyclic voltammetry curve of ferrocene is lower. As analyzed in Figure 1, these results are related to its substituents and effective electronic regulation. The constant current discharge curve of zinc-(ferrocenylmethyl)trimethylammonium iodide battery recorded by LAND CT2001A battery test instrument ( Figure 5B), where two discharge plateaus at 1.2 V and 1.7 V were also shown, which was consistent with the two cathodic peaks in the cyclic voltammogram. Figure 5C The density of states and Fermi level of the cathode electrode were further investigated by comparing the Fe 3+ / 2+ redox potential between (ferrocenylmethyl)trimethylammonium iodide (1.25 eV) and iodine (1.23 eV). 0 / I - It can be known that by regulating the side chain, the characteristics of the iron-benzene ring bond can be changed, and the Fe 3+ / 2+ redox energy is greatly changed.

[0064] The polarized electrode at different voltages was observed by in-situ Raman spectroscopy and ex-situ X-ray photoelectron spectroscopy to analyze the redox reaction in the charge storage process. As shown in Figure 5D and Figure 5E , when the charge and discharge test was carried out at a current density of 0.3 A g -1 , a 110 cm -1 I3 - stretching band was observed, and it is worth noting that I3 - species was also detected during the charging process when the voltage reached 1.2 V, so it can be known that the first voltage plateau (1.2 V) is the oxidation of I - to I 0 . When the voltage exceeds 1.3 V, the I3 - intermediate species disappears, that is, the I 0 / I - redox reaction is completed. In order to further clarify the evolution of the battery structure in the process, the valence state changes of iron and iodine at different voltages were monitored by X-ray photoelectron spectroscopy Figure 5F and Figure 5G ). Figures 6A to 6C The X-ray photoelectron spectroscopy of the electrode after the electrochemical test at 0.6 V, 1.3 V and 2.0 V was shown, and the peaks of iron, iodine and carbon can be identified; the valence state of neutral iodine was observed when charged to 1.3 V, and its position (iodine 3d3 / 2 at 631.2 eV, iodine 3d5 / 2 at 619.6 eV) remained stable during the subsequent charging process Figure 5F , which showed that iodine existed in the neutral valence state, which was consistent with the results observed in the Raman spectroscopy, further confirming that the first voltage plateau was related to the oxidation reaction of I-. Subsequently, the changes of iron under different polarization conditions were detected by X-ray photoelectron spectroscopy Figure 5G), before 1.3V, the iron 2p3 / 2 peak is located at 710.3eV, corresponding to the oxidized state of iron (II); with charging, its energy shifts up by 1.3eV to 711.6eV, and the position of the iron 2p1 / 2 peak is observed at 724.0eV, both of which show the presence of iron (III). These results show that Fe appears in the second voltage platform 3 + / 2+ In summary, both Raman spectroscopy and X-ray photoelectron spectroscopy show that structural changes related to multi-electron transfer occur during battery operation.

[0065] The electrochemical performance of (ferrocenylmethyl)trimethylammonium iodide was systematically evaluated using zinc metal as the counter electrode. Figure 7A As shown, in the range of 2 to 40A g -1 At all different current densities, two discharge platforms (1.2 V and 1.7 V) can be observed in the constant current charge-discharge curves of the zinc-(ferrocenylmethyl)trimethylammonium iodide full cell. -1 At the current density, the iron and iodine batteries have an extremely high specific capacity of about 421 mAh g 铁，碘 -1 (Zinc-(ferrocenylmethyl)trimethylammonium iodide full battery is about 202mAh g FcNI -1 ), which is one of the highest values ​​in zinc-organic batteries (at the same current density, compared with common organic cathodes such as polyaniline (PANI), polypyrrole (PPy), pyrene-4,5,9,10-tetraone (PTO), poly(benzoquinone sulfide) (PBQS), triphenylphosphine selenide (TP-Se), 1,8-octanediamine iodide (ODAI2), polyindole (PIn), tetrachloro-1,4-benzoquinone (p-chloroanisolequinone), 1,4-bis(diphenylamino)benzene (BDB), etc.), see for details. Figure 7B ), and its voltage is significantly higher than that of the second highest capacity pyrene-4,5,9,10-tetraone (0.8V). In addition, the battery with (ferrocenylmethyl)trimethylammonium iodide organic cathode also has excellent discharge rate, even at 40A g -1 At a high current density of 1.5 GHz, the zinc-(ferrocenylmethyl)trimethylammonium iodide battery can still provide 286 mAh g -1 The capacity is about 69% of the initial specific capacity ( Figure 7B ); and in 2A g -1 The discharge rate curve is highly reversible during the cycle. Figure 7C and Figure 7DThe comparison of the capacity contribution of the two discharge plateaus at different current densities was performed in the middle of the cell. The results show that the capacity contribution of the two plateaus only fluctuates slightly with the increase of current density, indicating that the iron and iodine redox centers have the effect of fast charge transfer.

[0066] Next, the cycling performance of the zinc-(ferrocenemethyl)trimethylammonium iodide battery was evaluated Figures 7E-7G . The gravimetric energy density of the full cell can be calculated by capacity-voltage integration. At a power density of 2500 W kg -1 , the estimated gravimetric energy density of the (ferrocenemethyl)trimethylammonium iodide battery is about 250 Wh kg FcNI -1 (about 516.8 Wh kg 铁，碘 -1 for the iron-iodine battery, see Figure 7E ), which is higher than known organic cathode materials such as polyaniline and Calix[4]quinone, and the (ferrocenemethyl)trimethylammonium iodide battery can still provide a capacity of about 155 Wh kg FcNI -1 at an ultrahigh power density of about 45,000 W kg FcNI -1 . In addition, if the performance of the (ferrocenemethyl)trimethylammonium iodide electrode is compared with other cathode materials (including organic cathodes, manganese oxides, Prussian blue analogues, vanadium-based materials, molybdenum sulfides, Scheffer phase Mo6S8) (see Figure 7E ), it has a more outstanding comprehensive performance in terms of voltage, cycle number, and energy density. In particular, the (ferrocenemethyl)trimethylammonium iodide battery can provide a reversible capacity of 372 mAh g -1 in the first 10 cycles (as shown in the interpolation graph in Figure 7F ), and the capacity can still be maintained at about 247 mAh g -1 after 5000 cycles at a current density of 5 A g -1 , with a high capacity retention rate of about 66% ( Figure 7F and Figure 7G ); more importantly, the double-voltage plateau characteristics of I 0 / I 1 and Fe 3+ / Fe 2+ are maintained during the entire cycle ( Figure 7G ).

[0067] In addition, a rechargeable lithium battery was assembled with a (ferrocenylmethyl)trimethylammonium iodide cathode and a lithium metal anode, and its performance was further evaluated. During the assembly process, the lithium-(ferrocenylmethyl)trimethylammonium iodide cathode was prepared as described above, but the anode was replaced with lithium foil. In an argon-filled glove box, 1M lithium salt (LiTFSI) was dissolved in a mixed solvent of 1,3-dioxolane (DOL) and ethylene glycol dimethyl ether (1:1 by volume) to prepare the electrolyte.

[0068] like Figure 8A As shown, in the cyclic voltammetry curve of the cathode, two peaks at 3.0 V (corresponding to I 0 / -1 Redox reaction) and 3.5V (corresponding to Fe 3+ / 2+ The obvious reduction peak of the redox reaction) corresponds to the two pairs of reversible potential platforms at the corresponding voltages in the constant current charge and discharge curve of the lithium-(ferrocenylmethyl)trimethylammonium iodide battery. The cyclic voltammetry curve and constant current charge and discharge characteristics of lithium-(ferrocenylmethyl)trimethylammonium iodide clearly show the high voltage multiple redox reactivity and high reversibility of the electrode. The maximum operating voltage of the (ferrocenylmethyl)trimethylammonium iodide battery is about 3.5V (such as Figure 8C (as shown), significantly higher than batteries using sulfur (2.2V), selenium (2.1V), tellurium (1.8V), and other iron-based batteries such as ferrous fluoride (2.6V) and ferric chloride (2.8V). In addition to exhibiting higher voltages in conversion lithium batteries, (ferrocenylmethyl)trimethylammonium iodide also has an advantage in terms of Earth's abundance, with its composition consisting of common major elements. In addition, due to its multi-electron transfer characteristics, (ferrocenylmethyl)trimethylammonium iodide also has a higher capacity than typical single-electron transfer batteries.

[0069] The discharge rate performance of the lithium-(ferrocenylmethyl)trimethylammonium iodide battery was further tested. The results showed that the battery exhibited stable reversible capacity at different current densities. For example, when the current density was 1, 2, 3, and 5 A g -1 When the reversible capacities are 400, 384, 370, and 349 mAh respectively 铁，碘 g -1 Even at 10A g -1 At a high current density of 1.5 GHz, the (ferrocenylmethyl)trimethylammonium iodide battery can still provide 327 mAh g -1 capacity, which is equivalent to 82% of the initial capacity (such as Figure 8D Thanks to its high voltage output and capacity, the battery can achieve a maximum energy density of 595Wh kg FcNI -1 , and at 30000W kgFcNI -1 still reached 463 Wh kg FcNI -1 energy density (as shown in Figure 9 ). In addition, the cycling performance of lithium-(ferrocenylmethyl)trimethylammonium iodide batteries was also evaluated, which still retained about 64% of the capacity after 1000 cycles at a current of 1 A g -1 (as shown in Figure 8E ). These results further confirmed the efficiency of the high-voltage, high-rate, multi-electron transfer chemistry of ferrocene derivatives in the preparation of high-performance battery cathode materials.

[0070] In addition, the basic mechanism of the power storage of the (ferrocenylmethyl)trimethylammonium iodide cathode was further analyzed by electrochemical experiments.

[0071] The cyclic voltammograms of (ferrocenylmethyl)trimethylammonium iodide at different scan rates (0.2-50 mV s -1 ) showed two pairs of cathodic and anodic peaks, which were consistent with the two pairs of platforms observed during the charging and discharging processes of zinc Figure 10A ) or lithium Figure 10B ) batteries. In addition, the two pairs of peaks were observed in a wide scan range, and the potential polarization (the difference between the reduction and oxidation potentials) increased slightly with the increase of the scan rate, showing that it had fast kinetics and excellent discharge rate performance. In Figure 11A and Figure 11B , the logarithmic values of the peak currents of the anodic and cathodic peaks at 1.2 V (iodine redox) and 1.7 V (iron redox, relative to Zn / Zn 2+ ) or 3.0 V (iodine redox) and 3.5 V (iron redox, relative to Li / Li + ) showed a good linear relationship with the logarithmic values of the scan rates (R 2 close to 1), which showed excellent discharge rate performance, even at a high scan rate of 50 mV s -1 . According to the calculation, the b values of I 0 / - and Fe 3+ / 2+ cathodic peaks in zinc-(ferrocenylmethyl)trimethylammonium iodide batteries were 0.88 and 0.81, respectively (0.79 and 0.72 in lithium-(ferrocenylmethyl)trimethylammonium iodide batteries), which showed that the anodic peaks of the two redox reactions exhibited the same pattern, revealing that the charge storage was affected by both diffusion and capacitive processes. In order to further distinguish the diffusion-controlled capacity and the capacitive capacity, the contribution ratios ( Figure 11C and Figure 11D ) at different scan rates were calculated.). The results show that at 0.5mV s -1 When the scan rate is increased, the capacitance process accounts for about 45% of the total capacity, and its capacitance contribution ratio gradually increases with the increase of the scan rate, and reaches 50mV s -1 When the discharge rate exceeds 80%, it shows that it has high discharge rate performance.

[0072] In addition, the redox reaction kinetics was evaluated by electrochemical impedance spectroscopy (recorded by CHI 760E multi-channel electrochemical detector) to detect its changes under different conditions from low voltage to medium voltage to high voltage ( Figure 11E First, the intersection of the Nyquist plot and the X-axis is represented by Rs. In the high-frequency region, the semicircular portion (charge transfer resistance, Rs) is not observed in the Nyquist plot at low voltage (no redox reaction occurs). ct ), showing its capacitive properties; at medium voltage (I 0 / - When the redox starts), a semicircle appears; at high voltage, two semicircles appear, which correspond to I 0 / - and Fe 3+ / 2+ The charge transfer resistance (R ct1 and R ct2 ) equivalent circuit model; where the three curves in the low-frequency region show similar slopes, indicating similar Warburg impedances caused by ion diffusion. However, in the Nyquist diagram, the reaction processes inevitably overlap. Therefore, in order to more clearly distinguish the reaction steps, the impedance spectrum is further analyzed using the distribution relaxation time (DRT) technique, where Figure 11F The relationship between the relaxation time distribution function (γ(τ)) and the relaxation time (τ) is shown. -6 The characteristic peaks of three reaction processes - P1, P2 and P3 - can be identified within seconds. The P3 peak at medium voltage can be attributed to the charge transfer reaction, while at high voltage, two peaks, P3-a and P3-b, appear because two redox centers are activated at this time. In addition, the P1 and P2 peaks with shorter relaxation times can be attributed to interfacial reactions, including desolvation and ion transport across the cathode-electrolyte interface. The peak with τ>100 seconds can correspond to ion diffusion related to Warburg diffusion in the electrode bulk phase ( Figure 12 ). It is worth noting that, 0 / - Compared with the reaction-related P3 or P3-b, Fe 3+ / 2 + The γ(τ) peak of the reaction-related P3-a appears at a shorter τ value, indicating that its electrochemical response is faster.

[0073] In summary, the present application improves the energy storage performance of ferrocene skeleton by introducing redox-active groups, and realizes multi-electron transfer chemistry. First, the design of (ferrocenylmethyl)trimethylammonium iodide fully utilizes the tunability of organic molecules, which can regulate the capacity, voltage, conductivity and redox kinetics of electrode materials. The introduced functional groups can greatly promote the redox activity of Fe 3+ / 2+ , and I 0 / - as an active redox center to carry out multi-electron transfer to support multi-electron transfer, thereby bringing high capacity characteristics. Next, compared with Zn / Zn 2+ and Li / Li + , the discharge platform of Fe 3+ / 2+ can be activated to 1.7V or 3.5V, respectively, because of the electron cloud interaction between the two active centers, which regulates the electronic energy related to the iron redox potential. In addition, the redox of I 0 / - and the activated high-voltage Fe 3+ / 2+ both have inherent fast kinetic characteristics, which are suitable for high-power cathodes. The rechargeable zinc / lithium-(ferrocenylmethyl)trimethylammonium iodide battery still shows excellent reversibility after thousands of cycles, and its capacity still exceeds 400mAh g Fe,I -1 (~200mAhg FcNI -1 ). Based on the mass of (ferrocenylmethyl)trimethylammonium iodide, the energy densities of zinc-(ferrocenylmethyl)trimethylammonium iodide and lithium-(ferrocenylmethyl)trimethylammonium iodide can reach 250 and 595Wh kg -1 , respectively, and maintain energy densities of 155 and 463Wh kg -1 at high powers of 45000W and 300000W, respectively.

[0074] The above description is provided to illustrate and describe the present application, and is not intended to exhaust or limit the present application to the precise form disclosed. Many modifications and changes will be apparent to those skilled in the art.

[0075] The above examples are selected and described in order to best explain the principles of the present application and its practical application, so that other skilled in the art can understand various embodiments of the present application and various modifications suitable for specific purposes.

Claims

1. A high voltage, high power battery, characterized in that, comprises at least one anode comprising one or more materials selected from lithium metal or zinc metal; at least one organic cathode comprising an active material comprising (ferrocenylmethyl)trimethylammonium iodide having the structure of formula (1): a porous polymer separator having a porosity of at least 30-90%; and an ether-based electrolyte.

2. The battery of claim 1, wherein the (ferrocenylmethyl)trimethylammonium iodide is ferrocene having a methyltrimethylammonium iodide group. When the negative electrode material is lithium metal, the maximum operating voltage of the battery is 3.5 V.

3. The battery of claim 1, wherein the methyltrimethylammonium iodide group can enhance the redox activity of Fe 3+ / 2+ and I 0 / - serves as an active redox center to undergo multi-electron transfer.

4. The battery of claim 3, wherein the electronic energy of the redox potential of iron is adjusted by the introduction of the methyltrimethylammonium iodide group, causing the discharge plateau of Fe 3+ / 2+ to rise by 0.5-1.0 V.

5. The battery of claim 1, wherein, When the negative electrode material is zinc metal, the maximum operating voltage of the battery is 1.7 V.

6. The battery of claim 1, wherein, mixing the (ferrocenylmethyl)trimethylammonium iodide, conductive particles, and binder in a solvent to obtain a mixture; 7. The battery of claim 2, wherein the method of making the at least one organic cathode comprises: and coating the mixture on a current collector and drying in a vacuum oven at 40-70 °C for at least 24 hours.

8. The battery of claim 7, wherein the current collector is selected from carbon cloth, carbon paper, graphite paper, titanium foil / titanium mesh, or high voltage high valence iodinated stainless steel.

9. The battery of claim 7, wherein the solvent is selected from mono-, di-, tri-, or tetraglyme.

10. The battery of claim 7, wherein the conductive particles are selected from reduced graphene oxide, activated carbon, hollow carbon spheres, or carbon cloth.

11. The battery of claim 7, wherein the binder is selected from styrene-butadiene rubber or polyvinylidene fluoride.

12. The battery of claim 1, wherein the ether-based electrolyte is an ether-based solvent with or without additives.

13. The battery of claim 12, wherein the ether-based solvent is selected from mono-, di-, tri-, or tetraglyme or any combination thereof mixed in a 1:1, 1:2, 1:3, or 1:4 volume ratio.

14. The battery of claim 12, wherein the additive is selected from saccharin, vanillin, sorbitol, or aromatic analogs.

15. The battery of claim 14, wherein the additive comprises a C=v, -F, -O-, or -SO3 group when the negative electrode material is zinc metal; and the additive comprises lithium fluoride, lithium nitrate, alkyne carbonates, alkyne ethylene carbonates, allyl ethylene carbonates, or lithium bis(fluoroborate) oxalate when the negative electrode material is lithium metal.

16. The battery of claim 12, wherein the ether-based electrolyte comprises a zinc salt or a lithium salt.

17. The battery of claim 16, wherein the zinc salt is selected from zinc bis(trifluoromethanesulfonyl)imide, zinc bis(fluorosulfonyl)imide, zinc triflate, zinc perchlorate, zinc acetate, zinc chloride, or zinc hexafluorophosphate.

18. The battery of claim 16, wherein the lithium salt is selected from lithium bis(trifluoromethanesulfonyl)imide, lithium triflate, lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium hexafluoroarsenate, or lithium bis(fluoroborate) oxalate. ​

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