CN116264316A

CN116264316A - Organic lithium-iodine battery based on two-electron transfer mechanism and manufacturing method and application thereof

Info

Publication number: CN116264316A
Application number: CN202111532349.6A
Authority: CN
Inventors: 支春义; 李新亮; 黄兆东; 陈泽
Original assignee: City University of Hong Kong CityU
Current assignee: City University of Hong Kong CityU
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2023-06-16

Abstract

The invention provides an organic lithium-iodine battery based on a two-electron transfer mechanism, a manufacturing method and application thereof, wherein the organic lithium-iodine battery comprises an anode, a cathode and organic electrolyte; wherein the positive electrode active material used for the positive electrode comprises iodide and/or bromide, and the organic electrolyte comprises an organic solvent containing a chlorine-containing additive. The organic lithium-iodine battery adopts iodide as the positive electrode active material, thereby avoiding the current use of I ₂ Instability and potential safety hazard existing as the positive electrode; an organic solvent containing a chlorine-containing additive is used as an organic electrolyte to provide excellent electrochemical performance through a two-electron conversion mode. It has higher capacity than conventional lithium-iodine batteryEnergy density and higher output voltage. In addition, the organic lithium-iodine battery has excellent low-temperature insensitivity, realizes 2500 cycles at the cost of 20% capacity attenuation at the temperature of minus 25 ℃, and can still stably work at the low temperature of minus 30 ℃.

Description

Organic lithium-iodine battery based on two-electron transfer mechanism and manufacturing method and application thereof

Technical Field

The invention relates to an organic lithium-iodine battery based on a two-electron transfer mechanism and a manufacturing method and application thereof, and belongs to the technical field of organic lithium-iodine batteries.

Background

The large discharge capacity and high output voltage should be two of the pursuit targets of the battery. Unfortunately, they are often not implemented simultaneously. The most sophisticated rocking or intercalation type lithium ion batteries are studied with a prominent high voltage output platform, but often unsatisfactory capacity. Such as LiCoMnO ₄ The output voltage of the positive electrode is as high as 5.3V, but the capacity is only 150mAh g ^-1 . The low discharge capacity is generally caused by ineffective ion intercalation and limited electron exchange, and the collapse of the positive electrode active material structure caused thereby. One promising alternative to this is a conversion cell based on a conversion mechanism, including lithium-iodine, bromine, sulfur, selenium, chlorine or oxygen systems. With abundant valence transitions, they tend to exhibit high discharge capacity with a large number of electron transfers, but their discharge voltage is often undesirable (e.g., 2.4V for lithium sulfur batteries, 3.4V for lithium bromine batteries, and 2.9V for lithium iodine batteries). While the shuttle effect of the system is particularly severe. Raising the discharge voltage of the conversion cell is an effective way to achieve high energy density, which requires the introduction of new redox mechanisms.

Iodine simple substance and bromine simple substance naturally have rich valence states, so that the iodine simple substance and bromine simple substance are hopeful to obtain higher output voltage by activating brand-new oxidation-reduction reaction. Currently, the power supply mechanism of lithium-iodine/bromine batteries is through X ^- /X ⁰ Reversible conversion between (X: iodine or bromine) redox couples is accomplished with single electron transfer. Notably, elemental bromine electrodes are based on a liquid-liquid switching mode, which is considered far less stable than elemental iodine electrodes. The intrinsic liquid nature and severe corrosiveness of elemental bromine make it difficult to apply to portable energy storageAn apparatus, which is generally applied to a liquid flow type energy storage device. Organolithium iodine batteries through I with disputes ^- /I ₃ ^- Or I ^- /I ₂ Reversible transformation of redox couple realizes charge transfer, and its theoretical discharge capacity is only 211mAh g ^-1 The output voltage is typically below 2.9V. However, I in a higher valence state ⁺ Cations are thermodynamically unstable in the electrolyte and hardly undergo reversible conversion. Previous studies related to iodate cations have not been successful in organic systems. Ideally, once I ⁺ The cation conversion is activated and stabilized, reversible I ⁰ /I ⁺ The oxidation-reduction will trigger a new conversion platform, the conversion potential ratio I ^- /I ⁰ The redox couple is about 0.5V high. In addition, the two-electron transfer mode is expected to double the theoretical capacity to 422mAh g ^-1 . More importantly, the energy density will achieve a significant increase of 200% over the original value (as shown in FIGS. 1a and 1 b).

Another disadvantage of lithium-iodine batteries is associated with the thermodynamic instability of elemental iodine. The elemental iodine spontaneously sublimates and is difficult to store for a long period of time even at room temperature. In addition, the lithium-iodine battery has slow dynamics and poor reversibility under severe low-temperature conditions, which mainly causes fast capacity decay and even failure of the lithium-iodine battery, and limits the application scene of the battery. Most of the current research is focused on developing porous hosts to contain iodine simple substances and reaction products, but host-guest interactions mainly stay on the physical adsorption level and have limited strength, so that the shuttle behavior of polyiodides in the circulating process is difficult to be effectively inhibited.

Therefore, aiming at the problems that the capacity of an organic iodine battery is low, the oxidation-reduction potential is low, the long cycle performance is poor, and the slow dynamics is easily identified in an organic lithium iodine (Li-I) battery and inferior to other similar conversion batteries and the like caused by a single electron transfer mechanism and a shuttle effect, the novel organic lithium iodine battery based on a two-electron transfer mechanism, and the manufacturing method and the application thereof have become technical problems to be solved in the field.

Disclosure of Invention

In order to solve the above-mentioned drawbacks and disadvantages, an object of the present invention is to provide an organolithium iodine battery.

Another object of the present invention is to provide a method for manufacturing the above organolithium iodine battery.

It is a further object of the present invention to provide the use of the organolithium iodine battery described above in an automobile, computer or robot. In the present invention, the new activated I ^- /I ⁺ The double electron transfer chemical reaction generated and realized by oxidation reduction brings greatly enhanced electrochemical performance for the organic lithium-iodine battery, which is far superior to the traditional lithium-iodine battery with I ^- /I ₃ ^- /I ⁰ The lithium-iodine battery provided by the invention is a high-performance organic lithium-iodine battery, has excellent capacity, energy density, electrochemical performance such as high output voltage and lasting cyclical stability, low-temperature insensitivity, safety, high efficiency and reversibility, and has good energy storage prospect in high-energy density equipment and great competitiveness in the future energy market.

In order to achieve the above object, in one aspect, the present invention provides an organolithium iodine battery, wherein the organolithium iodine battery comprises:

A positive electrode;

a negative electrode;

an organic electrolyte;

wherein the positive electrode active material used for the positive electrode comprises iodide and/or bromide, and the organic electrolyte comprises an organic solvent containing a chlorine-containing additive.

As a specific embodiment of the above organolithium iodine battery according to the present invention, wherein the negative electrode comprises lithium foil or graphite.

As an embodiment of the above organolithium iodine battery of the present invention, wherein the positive electrode comprises a current collector, a positive electrode active material, a conductive agent, and one or more binders.

As a specific embodiment of the above-described organolithium iodine battery of the present invention, wherein the amount of the positive electrode active material is 1 to 99wt%, the amount of the conductive agent is 0.1 to 90wt%, the amount of the binder is 0.01 to 20wt%, and the sum of the amounts of the positive electrode active material, the conductive agent, and the binder is 100%, based on 100% of the total weight of the positive electrode active material, the conductive agent, and the binder.

The specific materials of the conductive agent and the adhesive are not specifically required, and the conductive agent and the adhesive can be reasonably selected according to actual operation requirements. As a specific embodiment of the above organolithium iodine battery according to the present invention, the conductive agent is conductive particles.

As a specific embodiment of the above-described organolithium iodine battery of the present invention, wherein the iodide used as the positive electrode active material includes one or more of methyl ammonium iodide (methyl ammonium iodide), trimethyl ammonium iodide (Iodomethyltrimethylammonium iodide), tetrabutyl ammonium iodide (tetrabutylammonium iodide), tetrabutyl ammonium triiodide (tetrabutylammonium triiodide). The iodides used in the invention can provide active iodine, have thermal stability and can replace the traditional I ₂ 。

As a specific embodiment of the above-described organolithium iodine battery of the present invention, wherein the bromide used as the positive electrode active material includes tetramethyl ammonium bromide and/or tetramethyl ammonium tribromide.

As a specific embodiment of the organolithium iodine battery according to the present invention, the current collector comprises one of carbon cloth, carbon paper, aluminum foil, and foam nickel. In some embodiments of the invention, the carbon paper may be, for example, carbon nanotube paper.

As a specific embodiment of the above organolithium iodine battery of the present invention, wherein the concentration of the chlorine-containing additive ranges from 0.01 to 10M based on the total volume of the organic solvent.

As one embodiment of the organolithium iodine battery of the present invention, the chlorine-containing additive comprises LiCl, NH ₄ Cl、CaCl ₂ 、CsCl、FeCl ₂ 、MgCl ₂ 、KCl、NaCl、AgCl、ZnCl ₂ One or more of the following.

As a specific embodiment of the above organolithium iodine battery according to the present invention, the organic solvent containing chlorine-containing additive further comprises a lithium salt electrolyte.

As a specific embodiment of the above organolithium iodine battery of the present invention, wherein the concentration of the lithium salt electrolyte is in the range of 0.01 to 10M based on the total volume of the organic solvent.

As an embodiment of the organolithium iodine battery of the present invention, the lithium salt electrolyte comprises LiTFSI, liOTf, liPF ₆ 、LiClO ₄ 、LiBF ₄ 、LiAsF ₆ 、LiCF ₃ SO ₃ 、LiN(CF ₃ SO ₂ ) ₂ 、LiBOB、LiDFOB、LiFSI、LiNO ₃ Either LiCl.

As an embodiment of the organolithium iodine battery according to the present invention, the organic solvent includes one or more of acetonitrile (acetonite), dimethyl sulfoxide (dimethyl sulfoxide), tetrahydrofuran (tetrahydrofuran), propylene carbonate (propylene carbonate), ethylmethyl carbonate (ethyl methyl carbonate), ethylene carbonate (ethylene carbonate), dimethyl carbonate (dimethyl carbonate), ethylene carbonate (vinylene carbonate), propylene sulfite (propylene sulfite), methyl propionate (methyl propionate), fluoroethylene carbonate (fluoroethylene carbonate), dimethoxyethane (dimethoxyethane), dioxolane (dioxolane).

In another aspect, the present invention further provides a method for manufacturing the organolithium iodine battery, where the method includes:

and (3) manufacturing a positive electrode:

uniformly mixing an anode active material, a conductive agent and an adhesive in a solvent to obtain slurry, coating the slurry on a current collector, and drying to obtain the anode;

assembling an organic lithium-iodine battery:

and assembling the anode, the cathode and the organic electrolyte to obtain the organic lithium-iodine battery.

The battery assembling process is a conventional technical means in the field, and can be reasonably performed according to actual operation requirements.

In a further aspect, the invention also provides an application of the organic lithium-iodine battery in an automobile, a computer or a robot. The organic lithium-iodine battery provided by the invention has strong competitiveness in the fields of large-scale storage and power supply of electronic equipment in a large temperature range.

Compared with the prior art, the organic lithium-iodine battery provided by the invention has the beneficial technical effects that:

(1) The organic lithium-iodine battery provided by the invention has low cost and is simple to manufacture.

(2) The organic lithium-iodine battery provided by the invention adopts iodide as the positive electrode active material, thereby avoiding the current I ₂ Instability and potential safety hazard as positive electrode.

(3) The organic lithium-iodine battery provided by the invention adopts an organic solvent containing a chlorine-containing additive as an organic electrolyte, and provides excellent electrochemical performance through a double-electron conversion mode. It has higher capacity, energy density and higher output voltage than conventional lithium-iodine batteries. Specifically, in the embodiment of the invention, the safe and stable halide (methyl ammonium iodide) is developed as an electrochemical active iodine source to replace elemental iodine, so that the host can realize chemical adsorption of iodine rather than physical adsorption, and meanwhile, chlorine ions (0.1M) are introduced into the commercial electrolyte as additives to completely activate and stabilize the reversible I of the positive electrode of the halide (methyl ammonium iodide) ⁰ /I ⁺ And (3) oxidation-reduction reaction. Thus, the positive electrode of methyl ammonium iodide paired with the lithium metal negative electrode released two distinct discharge plateau, at 2.91V and 3.42V, respectively. Based on the method, a novel 3.42V high-voltage platform in the organic lithium-iodine battery doubles the total discharge capacity of the lithium-iodine battery to 408mAh g ^-1 Shows rapid redox kinetics and excellent long-term cycling stability. More importantly, the energy density can be increased to a surprising value of 1324Wh kg ^-1 Up to 238% of the traditional lithium-iodine batteries based on a single electron conversion reaction mechanism, is superior to all organometallic-iodine batteries (such as lithium-iodine, potassium-iodine, sodium-iodine, magnesium-iodine) and most rocking chair lithium-oxygen batteries reported so farA chemical battery system. In addition, the active voltage plateau region also significantly increases the effective energy output of the high voltage region.

(4) The organic lithium-iodine battery provided by the invention adopts the organic solvent containing the chlorine-containing additive, so that the organic lithium-iodine battery has excellent low-temperature insensitivity, the battery realizes 2500 times of circulation at the cost of 20% capacity attenuation at the temperature of minus 25 ℃, and the battery can still stably work at the low temperature of minus 30 ℃.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for the description of the embodiments will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1a is a schematic diagram of the mechanism of iodine conversion in a lithium-iodine battery.

Fig. 1b is a schematic diagram of electrochemical performance improvement in a lithium-iodine battery corresponding to the mechanism of iodine conversion shown in fig. 1 a.

FIG. 2a is a schematic diagram showing the crystal structure of MAI in test example 1 according to the present invention.

FIG. 2b is an SEM image of MAI of test example 1 according to the present invention.

FIG. 2c shows the Raman spectrum of MAI in test example 1 according to the present invention.

FIG. 2d shows XPS full spectrum of MAI in test example 1 according to the present invention.

FIG. 2e is a high resolution I3d XPS spectrum of MAI in test example 1 according to the present invention.

FIG. 2f is a graph showing the weight change of elemental iodine and MAI material at 60℃in test example 1 according to the present invention.

FIG. 2g is a graph showing the result of heat stability of elemental iodine at 60℃in test example 1 according to the present invention.

FIG. 2h is a graph showing the EDX mapping result of elemental iodine in test example 1 according to the present invention.

FIG. 2i is a graph showing the EDX mapping result of elemental carbon in test example 1 according to the present invention.

FIG. 2j is an EDX spectrum of MAI material in test example 1 of the present invention.

Fig. 3 is a graph showing the comparison of the active material iodine loadings in MAI and other composite iodine positive electrode materials in test example 2 of the present invention.

FIG. 4a shows the MAI// LDL// Li cell and the MAI// Cl-LDL// Li cell at 0.5mV s in test example 3 of the present invention ^-1 CV curve at sweep speed.

FIG. 4b is a graph showing the CV curves of MAI// Cl-LDL// Li cells at different sweep rates in test example 3 of the present invention.

FIG. 4c shows the b values of four redox peaks of MAI// Cl-LDL// Li cell calculated according to the formula (1) in test example 3 of the present invention.

FIG. 4d is a graph showing the CV curve of MAI// Cl-LDL// Li cells at various sweep rates in test example 3 of the present invention.

FIG. 4e shows the redox potential of MAI// Cl-LDL// Li cells at different scan rates in test example 3 of the present invention.

FIG. 4f shows that the MAI// LDL// Li cell and the MAI// Cl-LDL// Li cell were at 0.5. 0.5A g in test example 3 of the present invention ^-1 Charge-discharge curve at current density.

FIG. 4g is a GITT curve for MAI// Cl-LDL// Li cell of test example 3 showing the corresponding ion diffusion coefficient.

Fig. 4h is an enlarged GITT curve corresponding to fig. 4g and the measured overpotential of region I.

FIG. 4i is an enlarged GITT curve corresponding to FIG. 4g and the measured overpotential for region II.

Fig. 4j is an enlarged graph of the ion diffusion coefficient calculated based on the GITT curve shown in fig. 4 g.

FIG. 5a shows that the MAI// Cl-LDL// Li cells in test example 4 of the present invention were in the range of 0.5 to 5A g ^-1 Is provided.

Fig. 5b is a charge-discharge curve corresponding to the rate performance shown in fig. 5 a.

FIG. 5c shows that the MAI// Cl-LDL// Li cell was at 0.5. 0.5A g in test example 4 of the present invention ^-1 Long cycling performance at current density.

Figure 5d shows a test example 4 according to the invention,MAI// Cl-LDL// Li cells at 2.0. 2.0A g ^-1 Long cycling performance at current density.

FIG. 5e shows that the MAI// Cl-LDL// Li cell of test example 4 of the present invention was at 0.5. 0.5A g ^-1 Discharge curve at current density. The area covered by the vertical stripe dashed line represents a completely new I ⁰ /I ⁺ Redox contribution.

FIG. 5f is a graph showing the enhancement of energy density by voltage plateau region for MAI// Cl-LDL// Li cells at different rates in test example 4 of the present invention.

FIG. 5g is a graphical representation of the electrochemical performance (discharge capacity, average voltage and energy density) of MAI// Cl-LDL// Li cells versus prior art organometallic-iodine cells (the metals include lithium, potassium, sodium, magnesium) and intercalation lithium-oxide cells in accordance with test example 4 of the present invention.

Fig. 6a shows raman spectra of MAI positive electrodes at different selected states of charge (SOC) in test example 5 according to the present invention.

FIG. 6b is a UV-vis spectrum of MAI electrode at various selected states of charge in test example 5 according to the present invention.

FIG. 6c is an SEM image of MAI electrode after charging to 3.0V in test example 5 of the present invention.

FIG. 6d is an SEM image of MAI electrode after charging to 3.85V in test example 5 of the present invention.

FIG. 6e shows the EDX mapping result of the element I in the MAI electrode at 3.85V in test example 5.

FIG. 6f shows the EDX mapping result of the Cl element in the MAI electrode at 3.85V in test example 5 according to the present invention.

FIG. 7a shows calculated Cl/Cl-free/MAI// Cl-LDL// Li cells in test example 6 of the present invention ^- Cohesive energy of the redox product when ionic. The inset represents the optimized molecular structure of the redox product in different states.

FIG. 7b is an electron localization function of the redox product of test example 6 according to the present invention.

FIG. 7c shows calculated I-Cl in test example 6 of the present invention ₂ And the atomic charge of I and Cl in the I-Cl redox product.

FIG. 7d is a schematic representation of a possible transformation process in test example 6 according to the invention.

FIG. 7e is a graph showing the summary and comparison of cohesive energies of redox intermediates in different redox routes in test example 6 according to the present invention.

FIG. 8a is a graph of discharge capacity/cycle performance of MAI// Cl-LDL// Li cells at various temperature ranges in test example 7 of the present invention.

FIG. 8b is a graph of GCD for MAI// Cl-LDL// Li cells at 25 ℃, -25℃and-30℃in test example 7 of the present invention.

FIG. 8c is a graph showing dQ dV calculated based on the GCD curve shown in FIG. 8b in test example 7 of the present invention ^-1 Graph diagram.

FIG. 8d is a graph showing the long cycle performance results of MAI// Cl-LDL// Li cells at-25℃in test example 7 of the present invention.

FIG. 8e shows two MAI// Cl-LDL// Li cells connected in series in a test example 7 of the present invention, which were lit at-25℃at low temperature for a large size (160 mm. Times.100 mm) electroluminescent panel/cold plate.

FIG. 8f is an EIS spectrum of MAI// Cl-LDL// Li cell at various temperatures from 25℃to-30℃in test example 7 of the present invention.

FIG. 8g is Rct, ro values and capacity retention data for MAI// Cl-LDL// Li cells calculated at various temperatures ranging from 25℃to-30℃in test example 7 according to the present invention.

FIG. 8h shows the MAI// Cl-LDL// Li cell at-25℃and 1.0. 1.0A g in test example 7 of the present invention ^-1 GCD plot for cycling under conditions.

Detailed Description

It should be noted that the term "comprising" in the description of the invention and the claims and any variations thereof in the above-described figures is intended to cover a non-exclusive inclusion, such as a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements that are expressly listed or inherent to such process, method, article, or apparatus.

The "range" disclosed herein is given in the form of a lower limit and an upper limit. There may be one or more lower limits and one or more upper limits, respectively. The given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular ranges. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for specific parameters, with the understanding that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values listed are 1 and 2 and the maximum range values listed are 3,4 and 5, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

In the present invention, unless otherwise indicated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed throughout this disclosure, and "0-5" is only a shorthand representation of a combination of these values.

In the present invention, all the embodiments and preferred embodiments mentioned in the present invention may be combined with each other to form new technical solutions, unless otherwise specified.

In the present invention, all technical features mentioned in the present invention and preferred features may be combined with each other to form a new technical solution unless specifically stated otherwise.

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. The following described embodiments are some, but not all, examples of the present invention and are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

The medicines, battery materials and components used in the embodiments of the present invention are shown below, and are all commercially available conventional substances, which are directly used after being commercially available without any post-treatment.

Methyl ammonium iodide (ammonium methyl iodide, MAI,99%, aladin), lithium bis (trifluoromethane) sulfonimide salts (bis (trifluoromethane) sulfonimide lithium salt, liTFSI,99%, aladin), lithium nitrate (lithium nitrate, liNO) ₃ 99%, aladin), lithium chloride (lithium chloride, liCl,99%, aladin), dimethoxyethane (dimethoxyyethane, DME,99%, aladin), dioxolane (dioxalane, DOL,99%, aladin), polyvinylidene fluoride 470 (poly (vinyl 470 fluoride), PVDF, average Mw-400000, aladin), N-methylpyrrolidone (N-methyl-2-pyrrosidone, NMP,99%, aladin), ketjen black (ECP-600JD,Lion Corporation).

Example 1

The embodiment provides an organic lithium-iodine battery, which is prepared according to a preparation method comprising the following specific steps:

and (3) manufacturing a positive electrode:

mixing the MAI powder, ketjen black and PVDF in an N-methyl pyrrolidone solvent according to a mass ratio of 8:1:1, then vigorously stirring for 0.5h, coating the obtained slurry on flexible carbon cloth (with a thickness of 380 mu m), and drying in a vacuum oven at 70 ℃ for 24h to obtain the flexible anode. The area mass load of the positive electrode was controlled to be about 3mg cm ^-2 ；

Preparation of organic solvent (organic electrolyte) containing chlorine-containing additive:

the organic electrolyte is prepared by mixing 1M LiTFSI and 0.2M LiNO ₃ And 0.1M LiCl was dissolved in a solvent mixture consisting of DOL and DME in a volume ratio of 1:1 and prepared in a glove box filled with Ar atmosphere, the organic electrolyte was designated Cl-LDL (the solvent mixture consisting of DOL and DME contained 1M LiTFSI+0.2M LiNO) ₃ +0.1M LiCl)；

Assembling an organic lithium-iodine battery:

a CR2032 coin-type organolithium iodine battery, designated MAI// Cl-LDL// Li battery, was assembled with a lithium metal sheet (lithium foil) having a thickness of 300 μm as the negative electrode, the flexible positive electrode (disk having a diameter of about 12 mm) prepared as described above as the positive electrode, and a commercial Celgard 2400 having a thickness of 18 μm as the separator, and the prepared LiCl-containing organic solvent as the electrolyte, and the absolute MAI content in the MAI// Cl-LDL// Li battery was estimated to be about 2.7mg.

Example 2

and (3) manufacturing a positive electrode:

mixing trimethyl ammonium iodide powder, ketjen black and PVDF in an N-methyl pyrrolidone solvent according to a mass ratio of 8:1:1, then vigorously stirring for 0.5h, coating the obtained slurry on flexible carbon cloth (with a thickness of 380 mu m), and drying in a vacuum oven at 70 ℃ for 24h to obtain the flexible anode. The area mass load of the positive electrode was controlled to be about 3mg cm ^-2 ；

Assembling an organic lithium-iodine battery:

Comparative example 1

The comparative example provides an organolithium iodine battery which is prepared according to a preparation method comprising the following specific steps:

and (3) manufacturing a positive electrode:

mixing the MAI powder, ketjen black and PVDF in an N-methyl pyrrolidone solvent according to a mass ratio of 8:1:1, then vigorously stirring for 0.5h, coating the obtained slurry on flexible carbon cloth (380 mu m), and drying in a vacuum oven at 70 ℃ for 24h to obtain the flexible anode. The area mass load of the positive electrode was controlled to be about 3mg cm ^-2 ；

Preparing an organic electrolyte:

the organic electrolyte is prepared by mixing 1M LiTFSI and 0.2M LiNO ₃ Is dissolved in a solvent mixture consisting of DOL and DME in a volume ratio of 1:1 and prepared in a glove box filled with Ar atmosphere, the organic electrolyte is named LDL (the solvent mixture consisting of DOL and DME contains 1M LiTFSI+0.2M LiNO) ₃ )；

Assembling an organic lithium-iodine battery:

the CR2032 coin organolithium iodine battery, designated MAI// LDL// Li battery, was obtained by assembling with the above-described electrolyte using a lithium metal sheet (lithium foil) having a thickness of 300 μm as the negative electrode, a flexible positive electrode (disc having a diameter of about 12 mm) prepared as described above as the positive electrode, and a commercial Celgard 2400 having a thickness of 18 μm as the separator, and the absolute MAI content in the MAI// LDL// Li battery was estimated to be about 2.7mg.

Test example 1

In the test example, analysis such as crystal structure (XRD), SEM, raman spectrum, high-resolution I3D XPS, thermogravimetric, EDX and the like is respectively carried out on MAI powder, wherein X-ray diffractometer equipment used for XRD analysis is Bruker, D2 Avance and is used for recording XRD patterns; SEM analysis used a cold field emission scanning electron microscope, model SU4800, hitachi, for characterizing the morphology and microstructure of the material; XPS analysis uses an X-ray photoelectron spectrometer, the model of which is ESCALAB 250), for analyzing the surface composition of the material; raman spectroscopy analysis uses a Renishaw 2000 microscope device and raman spectra are collected in the device.

Wherein, the MAI has a crystal structure schematic, an SEM image, a Raman spectrum and a high fractionThe mass change of the iodine simple substance and MAI material at 60deg.C is shown in figures 2 a-2 e. As can be seen from FIG. 2a, in methyl ammonium iodide, iodide ion I ^- Bonding with N through ionic bond. A Scanning Electron Microscope (SEM) image as shown in fig. 2b shows that the MAI crystal surface appears to be pit-like. The corresponding x-ray spectra (FIGS. 2 h-2 j) reveal that iodine (I) and carbon (C) elements are uniformly distributed therein in a mass ratio of about 79:21.

As can be seen from the Raman spectrum shown in FIG. 2c, 110cm ^-1 The main peak at which is related to the vibration of the N-I bond.

In addition, the detailed valence state of the iodine (I) element was analyzed by x-ray photoelectron spectroscopy (XPS) technique. Three elements C, N, I were detected in XPS whole spectrum as shown in fig. 2 d. In the high resolution I3d XPS spectrum shown in fig. 2e, two distinct peaks were identified at positions 619eV and 630eV, respectively, corresponding to N-I bonds, where I exhibits a negative valence.

Also notable is that: the MAI halide has excellent thermal stability and can be used as an active substance to replace the traditional elemental iodine. As shown in the weight change diagrams of the iodine simple substance and the MAI material at the temperature of 60 ℃ and the thermal stability result diagram of the iodine simple substance at the temperature of 60 ℃ shown in fig. 2f and 2g, the long-acting stability of the MAI material is tested by taking the iodine simple substance as a reference, the whole test is completed in a glove box filled with nitrogen, and the test temperature is set at 60 ℃. The iodine simple substance is completely volatilized out within 2 hours without being discharged, and the MAI material can keep stable weight for a long time. The results shown in fig. 2f show that the MAI material loses only 1.8wt.% weight in 480h and that the high probability is due to volatilization of the adsorbed water.

Test example 2

The mass fraction of active iodine in the positive electrode (the mass of pure iodine) is an important index for representing the availability of the positive electrode. To this end, the present test example examined the loading of active material iodine in MAI and other composite iodine cathode materials, and the comparison obtained was shown in fig. 3, and it can be seen from fig. 3 that the flexible cathode provided in example 1 had a satisfactory loading of active material iodine (elemental iodine) of 63wt.%, calculated as weight of active material iodine element in the electrode per total electrode weight x 100% (79 wt.% iodine in MAI, 80wt.% MAI in the entire flexible cathode), which was higher than the loading of active material iodine in most of the existing composite electrodes, such as porous carbon-iodine, metal organic framework-iodine, polyvinylpyrrolidone-iodine.

Test example 3

The present test examples examined the electrochemical performance of MAI// Cl-LDL// Li cells and MAI// LDL// Li cells, respectively, and during the examination of electrochemical performance, the electrolyte and lithium negative electrode of the cells should be overused to ensure complete electrochemical conversion of the positive electrode of the cells examined. Specifically, constant current charge/discharge measurements of the battery were performed on a LAND CT2001A battery test device. Cyclic Voltammetry (CV) data and Electrochemical Impedance Spectroscopy (EIS) data were recorded using a CHI 760D multichannel electrochemical workstation. In addition, all capacities and energy densities in this test example were calculated based on the pure iodine content in the MAI positive electrode.

FIG. 4a shows that MAI// LDL// Li cells and MAI// Cl-LDL// Li cells were at 0.5mV s ^-1 Cyclic Voltammetry (CV) curves at sweep rate. As can be seen from FIG. 4a, MAI// LDL// Li cells exhibited a typical pair of redox peaks at 3.00/2.96V voltage, corresponding to I ^- /I ₃ ^- The redox couple is reversibly transformed. In sharp contrast, two distinct redox peaks were identified in MAI// Cl-LDL// Li cells, with a pair of redox peaks at 3.45/3.34V in addition to the 3.00/2.96V peak positions mentioned above, indicating that a new reversible chemistry was activated. Notably, a voltage difference of 0.4-0.5V for the two reduction peaks suggests that the new redox couple may be derived from I ⁰ /I ⁺ A redox couple. The narrow half-peak width and strong current response of the new peak mean that the reaction has excellent kinetics and reversibility.

To elucidate the dynamic evolution of MAI// Cl-LDL// Li cells with a two-stage redox process, the present test example tested MAI// Cl-LDL// Li cells at 0.1-1.0mV s ^-1 The CV curve in the sweep speed range is shown in FIG. 4b, and it can be seen from FIG. 4b that, inAt all rates, two similar pairs of redox peaks were identified in the CV curve, meaning that the reversible conversion was efficient and stable. With the benefit of efficient conversion kinetics, the redox potential is only from 0.1mV s ^-1 2.97/3.36V offset to 1.0mV s at scan speed ^-1 The voltage hysteresis is only 0.02V and 0.05V at 2.95/3.31V.

To elucidate the charge storage mode of MAI// Cl-LDL// Li cells, the present test example separated the response current and further calculated the b values of the four redox peaks based on the following equation (1):

i＝av ^b formula (1);

in equation (1), i and v represent the response peak current and the application scan rate, respectively. In general, when b is equal to 1, the reaction is capacitively limited. For the diffusion control process, b is close to 0.5. As shown in FIG. 4c, the b values of the two pairs of redox peaks were calculated to be 0.60/0.58 and 0.63/0.57, respectively. Thus, new I ⁰ /I ⁺ Redox couples are believed to be commonly controlled by both capacitive and diffusion control processes, the latter of which predominates.

At 2 to 10mV s ^-1 At a large scan rate of (2) the whole I ^- /I ⁺ The transformation retains the well-defined two-stage character as shown in figure 4 d. As a complementary analysis, this test example extracts and compares the reduction potential of two individual reactions as a function of scan rate, as shown in fig. 4 e. Notably, when the scan rate is increased by a factor of 100, I ⁰ /I ⁺ The galvanic redox couple showed only a 0.24V voltage hysteresis, indicating its excellent conversion kinetics. Furthermore, the electrochemical difference of the two cells is also manifested in the constant current measurement. FIG. 4f shows a cross-sectional view at 0.5A g ^-1 Constant current charge/discharge (GCD) curves for both cells at current density, as can be seen in FIG. 4f, MAI// LDL// Li cells have only I ^- /I ⁰ Conversion brings about a discharge plateau at a potential of 2.91V based on I ^- /I ⁺ Redox MAI// Cl-LDL// Li cells released two distinct discharge plateau at 2.91V and 3.42V, consistent with CV results described above. In addition, the discharge capacity of MAI// Cl-LDL// Li cells is significantly higher than that of MAI// LDL// Li cellsThe amounts are respectively 408mAh g ^-1 And 197mAh g ^-1 . Note that the former increased capacity is entirely due to the presence of the 3.42V plateau region, i.e. active I ⁰ /I ⁺ And (5) conversion.

In addition, the present test examples were also characterized by constant current intermittent titration (GITT) using methods conventional in the art to clarify the superior kinetics of the cell in terms of ion diffusion. The GITT curve (voltage vs. time) as shown in fig. 4g clearly reveals the two-stage discharge pattern of the overall redox process. The two different discharge plateau observed exhibited low overpotential of 17mV and 30mV in both region I and region II (as in fig. 4h and fig. 4I), which confirm their lower equilibrium potential and rapid ion diffusion kinetics. Based on the GITT curve, the present test example further calculated the corresponding ion diffusion coefficient. As shown in the inset in fig. 4g and in fig. 4j, the ion diffusion coefficient fluctuation of the cell at region I (2.8-3.0V) and region II (3.3-3.5V) was not significant, unlike the intercalation electrode.

Test example 4

After revealing a completely new redox mechanism for MAI// Cl-LDL// Li cells, the present test example evaluated the electrochemical performance of the cells in constant current mode. In examining electrochemical performance, the electrolyte and lithium negative electrode of the cell should be overused to ensure complete electrochemical conversion of the positive electrode of the cell under examination. Specifically, constant current charge/discharge measurements of the battery were performed on a LAND CT2001A battery test device. In addition, all capacities and energy densities in this test example were calculated based on the pure iodine content in the MAI positive electrode.

FIG. 5a shows a range from 0.5 to 5A g ^-1 As can be seen from fig. 5a, the rate capability of the battery at a wide range of current densities is 0.5A g ^-1 When the discharge capacity of the battery reaches 408mAh g ^-1 Near the theoretical upper limit of the two electron transfer mechanisms (422 mAh g ^-1 ). As the current density increased, the discharge capacities remained at 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 and 5.0A g, respectively ^-1 374, 356, 342, 336, 327, 320, 315, 311, 296mAh g at current density ^-1 . At the height of 5.0A g ^-1 The lower part of the upper part is provided with a lower part,the battery capacity retention exceeds 73%, indicating superior redox kinetics and reversibility. More impressively, both discharge plateaus remain intact at all scan rates, as shown by the corresponding GCD curves of fig. 5b, and as can be seen from fig. 5b, when the current density increases ten times, only a small plateau hysteresis is identified: the plateau at the 3.42V potential is 0.14V and the plateau at the 2.91V potential is 0.16V. Another notable advantage is the polarization voltage of the GCD, where the polarization voltage value at the 2.91V plateau is 0.08V and the polarization voltage value at the 3.42V plateau is 0.07V. In addition, the test example also evaluates the battery at 0.5A g ^-1 As shown in fig. 5c, it can be seen from fig. 5c that after 500 cycles there is only 15% capacity fade, corresponding to a capacity fade rate of less than 0.03% per cycle. At 2.0A g ^-1 At current density, 1300 long cycles only caused a 20% capacity loss, where the cycling stability of the cell was verified, as shown in particular in fig. 5 d.

By a pair of 0.5. 0.5A g ^-1 The GCD curve below was subjected to a simple mathematical analysis to further clarify that the curve was due to I ⁰ /I ⁺ The electrochemical performance achieved by the presence of redox is significantly improved. MAI// Cl-LDL// Li cells at 0.5. 0.5A g ^-1 The discharge curve at current density is shown in fig. 5e, and it can be seen from fig. 5e that the activation of the new conversion chemistry doubles the reversible capacity, bordering the first inflection point of the 3.42V plateau. Note that the capacity expansion of the 3.42V platform is more significant because of the traditional I ^- /I ₃ ^- The redox 2.91V plateau corresponds to only two-thirds of the electron transfer per iodine (I). Thus, the cell achieved a 138% increase in energy density, as indicated by the area covered by the vertical striped dashed line in fig. 5 e. The results of the enhancement of the energy density by the plateau region of MAI// Cl-LDL// Li cells at different rates are shown in FIG. 5f, as can be seen from FIG. 5f, even at 4.5A g ^-1 The value is still kept around 102%. At 1.5A g ^-1 、2.5A g ^-1 And 3.5. 3.5A g ^-1 The improvement of the energy density is 132%, 111% and 106% respectively under the current density, so that the lithium-iodine battery is greatly optimizedActual power supply capability. To demonstrate the superiority of the new organolithium iodine battery, MAI// Cl-LDL// Li battery, the present test example also compared the electrochemical performance (e.g., discharge capacity, average voltage and energy density) of MAI// Cl-LDL// Li battery with other reported organometal-iodine batteries (the metals include lithium ion, potassium ion, sodium ion, magnesium ion) and intercalation-type lithium-oxide batteries, and the results are shown in FIG. 5g, and it can be seen from FIG. 5g that the average output voltage, capacity and energy density of MAI// Cl-LDL// Li battery are superior to all reported metal-iodine batteries, including conventional organolithium iodine batteries and intercalation-type lithium-oxide batteries.

Test example 5

Multiple experimental characterization, including UV-vis spectroscopy, raman spectroscopy, scanning electron microscopy and energy spectrum analysis, revealed a potential redox mechanism for two electron transfer of the novel organolithium iodine battery. The scanning electron microscope analysis uses a cold field emission scanning electron microscope, the model of which is SU4800, hitachi, and is used for representing the morphology and microstructure of the material; raman spectroscopy analysis uses a Renishaw 2000 microscope device and raman spectra are collected in the device; ultraviolet-visible absorption spectra were collected using a spectrometer model Shimadzu UV-3600.

FIG. 6a shows the Raman spectra of MAI anodes at various selected states of charge (SOCs), i.e., the flexible anodes in example 1, as can be seen in FIG. 6a, at 110cm under a full discharge of 2.0V ^-1 The strongest peak detected at this point is due to I ^- Ions, similar to I of the original MAI material ^- Ions; as the charging process progressed to 3.0V,167cm ^-1 A new main peak appears at 110cm ^-1 The main peak at the point is significantly reduced, corresponding to the slave I ^- To I ₃ ^- A first conversion stage of anions; at full charge of 3.6V and 3.85V, the spectrum is significantly changed from 237cm ^-1 And 328cm ^-1 Two newly emerging peaks at the two peaks, corresponding to stretching of the Cl-I bond in the second conversion stage, are controlled, knowing the introduced chlorine (Cl) ^- ) Ion stabilizes the I generated at high potential ⁺ And (3) cations.

The UV-vis absorption spectra further complements the Raman results described above for the characterization of the iodine redox process, with the UV-vis spectra of the MAI electrode at different selected states of charge shown in FIG. 6 b. To avoid unexpected interference with subsequent processing, the present test example directly measured the outer surface of the MAI electrode at different SOCs to collect all spectra. In these graphs as shown in fig. 6b, the evolution of the peak position is still trackable. I ^- The signal of the excitation of the ion at 2.0V appears at 216cm ^-1 Position, I ₃ ^- The signal of excitation of the ion at 3.0V appears at 270-290cm ^-1 Clearly shows that I in the initial stage ^- /I ₃ ^- Conversion by oxidation-reduction; when charged to a higher voltage, these characteristic peaks completely disappear and instead appear at 390-480cm ^-1 Broad peak at this stage I ₃ ^- The ions are continuously oxidized to I ⁺ Ions; furthermore, after both redox phases, the present test example visually examined the electrode surface by SEM techniques, which showed that the MAI electrode microstructure remained intact after cycling, still with the original porous features, and no regional shedding or cracking was observed, as shown in fig. 6 c-6 d. Meanwhile, the EDX spectrogram results as shown in fig. 6e to 6f confirm the coexistence of I and Cl elements.

Test example 6

To further understand the two electron transfer reactions carried out by the MAI// Cl-LDL// Li cell at the atomic scale, the present test example performs density functional theory (Density functional theory, DFT) calculations on the MAI// Cl-LDL// Li cell. All first principles calculations in this test example were performed by Vienna ab initio simulation package (VASP) using a plane wave based method (see: kress G, furthmuller J. Effective iterative schemes for ab initio total-energy calculations using a plane-wave basic Review B1996,54 (16): 11169-11186. And Kress G, joubert D. From ultrasoft pseudopotentials to the projector augmented-wave method. Physical Review B1999,59 (3): 1758-1775.). The exchange-related interactions are approximated by a generalized gradient in Perdew-Burke-Ernzerhof (PBE) (GGA) description (see: perdew P, chevary A, vosko H, jackson A, pederson R, singh J, et al, atoms, molecular, solids, and surface-applications of the generalized gradient approximation for exchange and correction.physical Review B1992,46 (11): 6671-6687. And Perdew P, wang Y.exact and simple analytic representation of the electron-gas correction-energy.physical Review B1992,45 (23): 13244-13249.) and core valence electron interactions are calculated using enhanced wave (PAW) pseudopotentials. Furthermore, vdW-D3 correction was invoked in all calculations to account for dispersion interactions. Here the supercell of MAI is 2X 3X 1. The plane wave basis set uses an energy cutoff of 500eV and the brillouin zone uses a Monkhorst-Pack k-point grid with a 2X 1 grid. In the calculation is provided with

To build up a solid surface. The convergence criteria of the residual force and energy are set to +.>

And 10 ^-6 eV (see: li B, wang C, zhang Y, wang Y.high CO) ₂ absorption capacity of metal-based ionic liquids: A molecular dynamics student.Green Enregy Environment 2020.doi.org/10.1016/j.gee.2020.04.009. To elucidate the mechanism of Cl to I ion conversion, the present test example simulates several systems, including I ₃ 、ICl、I ₂ Cl is shown in particular in FIGS. 7 a-7 e. To measure the stability of different systems, cohesive Energy (EC) was calculated from DFT calculations according to the following formula (2).

In formula (2), m and n are the number of I, cl atoms; esys, E _I 、E _Cl And Esub are the energies of the system, isolated atom I, isolated atom Cl and MAI substrates, respectively. The larger the EC value, the higher the thermodynamic stability of the corresponding system.

Designed byThe two-step reaction proceeds from initial I ^- Ions begin. The cohesive energy curves in the different routes are plotted in fig. 7a, together with the redox product, the inset shows the optimized molecular structure of the redox product accordingly. The calculation results solve two key problems: free Cl ^- Whether or not to facilitate I ⁺ Is the generation and stabilization of ions? And what is the most likely redox product? Without Cl ^- ，I ₃ ^- Direction I ⁺ Is affected by the high energy barrier, thereby producing I ⁺ Insufficient cohesive energy means their thermodynamic instability. Research has found that the introduced Cl ^- Significantly reduce the slave I ₃ ^- Anions to I ⁺ Potential barrier for cation transition. In addition, the halogen-to-halogen redox products were identified as more favorable I-Cl than I-Cl due to the high cohesive and low reaction energy barrier of I-Cl ₂ As shown in fig. 7 e.

In addition, the present test examples analyze the bond patterns and lone pair electron distributions of possible redox products by means of a relevant Electron Localization Function (ELF). By definition, the value of ELF is between 0 and 1, with an upper limit of 1 representing complete electron localization and a lower limit of 0 representing complete electron delocalization. As shown in FIG. 7b, the ELF model illustrates Cl ^- And I ⁺ Stable and robust electrical coupling between can be detected in I-Cl, rather than in I-Cl ₂ Is a kind of medium. This finding also shows that the redox product ratio in I-Cl is I-Cl ₂ Is more stable. Furthermore, the calculated atomic charge indicates that the charge states of I and Cl in I-Cl are opposite, indicating a strong interaction and significant electron transfer between them, as shown in fig. 7 c. For I-Cl ₂ I and Cl of (a) are the same in their charge states, and electron transfer is weak. In summary, in the Cl-containing electrolyte system, I-Cl is the final dominant redox product, matching the cohesive energy analysis described above. Thus, the I-Cl bonds detected in Raman spectroscopy can be attributed to the I-Cl phase rather than I-Cl ₂ And (3) phase (C).

Based on the above analysis, the redox reaction based on the two electron transfer mechanism was clarified. As shown in FIG. 7d, during charging, the original I ^- The ions first oxidize to form I ₃ ^- (I ⁰ ) Corresponding to step 1 of the redox process; then, by forming I-Cl, cl in the electrolyte ^- Ion binding and stabilization of positive I ⁺ Ions.

Test example 7

Under severe low temperature conditions, the slow kinetics and poor reversibility of the battery often lead to rapid capacity decay and even failure, thereby limiting the application scenarios of the battery. Thus, in view of the superior kinetics achieved by the entirely new conversion chemistry, the present test example further evaluates the environmental suitability of the new conversion cell, i.e., MAI// Cl-LDL// Li cell, over a wide temperature range of 25℃to-30 ℃. In this test example, electrochemical Impedance Spectroscopy (EIS) data was recorded using a CHI 760D multichannel electrochemical workstation. All capacities and energy densities were calculated based on the pure iodine content in the MAI positive electrode.

FIG. 8a shows a graph of the discharge capacity of MAI// Cl-LDL// Li cells over different temperature intervals, in which it can be seen from FIG. 8a that the cells can always operate stably, the discharge capacity of which decays with decreasing temperature. Notably, at-30 ℃, the battery still can supply 51% of room temperature capacity, without failure or even fluctuation. Specifically, the retention at 15℃was 95%, the retention at 5℃was 91%, the retention at-5℃was 87%, the retention at-15℃was 80%, and the retention at-25℃was 67%. FIG. 8b shows the GCD curves of the cell at 25 ℃, -25 ℃ and-30 ℃ and it can be seen from FIG. 8b that all GCD curves contain two distinct charge/discharge plateau pairs, which clearly electrochemical characteristics strongly demonstrate the correlation with I ^- /I ⁺ The redox-related two-stage redox chemistry is temperature insensitive.

In addition, the test example further calculated a differential capacitance-voltage curve (dQ dV ^-1 ) To elucidate the kinetic evolution as shown in fig. 8 c. As expected, at all temperatures, the curve contains the values of I ₃ ^- /I ⁰ And I ₀ /I ⁺ Two pairs of fitted peaks corresponding to the two redox reactions. And I ₃ ^- /I ⁰ In comparison, I ⁰ /I ⁺ The Y-axis value of the redox couple is higher, due to its larger plateau region, consistent with the GCD results described above. The decrease in potential polarization is mainly due to the decrease in ion transport kinetics caused by the temperature sensitivity of the electrolyte.

EIS spectra of MAI// Cl-LDL// Li cells at different temperatures from 25℃to-30℃are shown in FIG. 8f, and Rct, ro values and capacity retention data of MAI// Cl-LDL// Li cells calculated at different temperatures from 25℃to-30℃are shown in FIG. 8g, as shown in the EIS spectra in FIG. 8f, the Rct (charge transfer resistance) value gradually increases as the temperature decreases, increasing from about 22. OMEGA.at 25℃to 532. OMEGA.at-30℃indicating partial obstruction of ion diffusion in the electrolyte. The capacity retention versus temperature graph then shows the opposite evolution trend, as shown in fig. 8 g. In addition, the present test examples also performed a long cycle test of the battery at-25 ℃. The long cycle performance results of MAI// Cl-LDL// Li cells at-25℃are shown in FIG. 8d, MAI// Cl-LDL// Li cells at-25℃and 1.0. 1.0A g ^-1 The GCD graph for cycling under conditions is shown in fig. 8h, and it can be seen from fig. 8d and 8h that the cell is capable of exhibiting good long-term cycling characteristics at low temperatures, which achieve up to 2500 cycles at the cost of 20% capacity fade, while maintaining nearly 100% coulombic efficiency.

In addition, as shown in FIG. 8e, two MAI// Cl-LDL// Li cells in series can illuminate a large-sized (160 mm. Times.100 mm) electroluminescent panel/cold plate at a low temperature of-25 ℃.

In summary, aiming at the defects of low voltage and low capacity of the traditional organic lithium-iodine battery, the embodiment of the invention provides an effective inter-halogen activation/activation strategy, and stable and reversible oxidation reduction of multi-valence iodine is realized through modifying electrolyte. Completely new activated I ^- /I ⁺ The redox mechanism brings about the two-electron transfer chemistry which is desired, greatly enhances the electrochemical performance of the organolithium iodine battery, and far exceeds the traditional I-based battery ^- /I ₃ ^- /I ⁰ Corresponding electrochemical performance of the converted like cells. Specifically, in the novel organic lithium-iodine battery provided by the embodiment of the invention, a triggered 3.42V voltage platform dischargesDoubling the capacity to 408mAh g ^-1 . More notably, the resulting energy density (1324 Wh kg ^-1 ) To the previous report (typically 550-580Wh kg ^-1 ) 238%. The additional energy contribution comes from the newly triggered high voltage plateau region, significantly improving the effective output capacity of the battery. In addition, the brand new oxidation-reduction reaction has good dynamics and circulation stability. The I generated by the introduced chloride ions in the activated and stable high-voltage interval is mainly analyzed through experimental analysis and DFT simulation ⁺ The important role played in the cation reveals that Cl-containing ^- The specific action modes of the additive are as follows: it is prepared by I-Cl method and I ⁺ Bonding, effectively promote I ⁺ Is generated and stabilized. Meanwhile, the new redox reaction exhibits excellent low-temperature environmental adaptability. The invention shows a brand new two-electron transfer iodine chemistry, which remarkably improves electrochemical performance parameters such as output voltage, capacity and the like of the organic lithium-iodine battery and realizes unprecedented high energy density. The efficient interhalogen strategy developed by the invention is expected to be applied to other halide conversion systems.

The foregoing description of the embodiments of the invention is not intended to limit the scope of the invention, so that the substitution of equivalent elements or equivalent variations and modifications within the scope of the invention shall fall within the scope of the patent. In addition, the technical features and the technical features, the technical features and the technical invention can be freely combined for use.

Claims

1. An organolithium iodine battery, characterized in that the organolithium iodine battery comprises:

a positive electrode;

a negative electrode;

an organic electrolyte;

2. The organolithium iodine battery according to claim 1 wherein the negative electrode comprises a lithium foil or graphite.

3. The organolithium iodine battery according to claim 1 wherein the positive electrode comprises a current collector, a positive electrode active material, a conductive agent, and one or more binders.

4. The organolithium iodine battery according to claim 3, wherein the amount of the positive electrode active material is 1 to 99wt%, the amount of the conductive agent is 0.1 to 90wt%, the amount of the binder is 0.01 to 20wt%, and the sum of the amounts of the positive electrode active material, the conductive agent, and the binder is 100%, based on 100% of the total weight of the positive electrode active material, the conductive agent, and the binder.

5. The organolithium iodine battery according to any one of claims 1 to 4, wherein the iodide used as the positive electrode active material comprises one or more of methyl ammonium iodide, trimethyl ammonium iodide, tetrabutyl ammonium triiodide.

6. An organolithium iodine battery according to any of the claims 1-4 wherein the bromide used as positive electrode active material comprises tetramethyl ammonium bromide and/or tetramethyl ammonium tribromide.

7. The organolithium iodine battery according to claim 3 or 4 wherein the current collector comprises one of carbon cloth, carbon paper, aluminum foil, foam nickel.

8. The organolithium iodine battery according to claim 1, wherein the concentration of the chlorine-containing additive ranges from 0.01 to 10M based on the total volume of the organic solvent.

9. The organolithium iodine battery according to claim 1 or 8, wherein the chlorine-containing additive comprises LiCl, NH ₄ Cl、CaCl ₂ 、CsCl、FeCl ₂ 、MgCl ₂ 、KCl、NaCl、AgCl、ZnCl ₂ One or more of the following.

10. The organolithium iodine battery according to claim 1 wherein the organic solvent containing chlorine-containing additive further comprises a lithium salt electrolyte.

11. The organolithium iodine battery according to claim 10, wherein the concentration of the lithium salt electrolyte ranges from 0.01 to 10M based on the total volume of the organic solvent.

12. The organolithium iodine battery according to claim 10 or 11 wherein the lithium salt electrolyte comprises LiTFSI, liOTf, liPF ₆ 、LiClO ₄ 、LiBF ₄ 、LiAsF ₆ 、LiCF ₃ SO ₃ 、LiN(CF ₃ SO ₂ ) ₂ 、LiBOB、LiDFOB、LiFSI、LiNO ₃ Either LiCl.

13. The organolithium iodine battery of any of claims 1-4,8 and 10-11 wherein the organic solvent comprises one or more of acetonitrile, dimethyl sulfoxide, tetrahydrofuran, propylene carbonate, methyl ethyl carbonate, ethylene carbonate, dimethyl carbonate, ethylene carbonate, propylene sulfite, methyl propionate, fluoroethylene carbonate, dimethoxyethane, dioxolane.

14. The method for manufacturing the organolithium iodine battery according to any one of claims 1 to 13, comprising:

and (3) manufacturing a positive electrode:

assembling an organic lithium-iodine battery:

15. Use of the organolithium iodine battery of any of claims 1-13 in an automobile, a computer or a robot.