CN111864199A - an alkali metal ion battery - Google Patents

Abstract

The invention provides an alkali metal ion battery, comprising a positive electrode, a negative electrode and an electrolyte, the material of the positive electrode comprises a carbon-composite iron-phosphorus-selenium compound, a conductive agent and a binder, and the carbon-composite iron-phosphorus-selenium compound comprises A carbon layer and an iron phosphorus selenide compound, the carbon layer covering the surface of the iron phosphorus selenide compound. The present application completes the analysis of the sodium storage performance of the carbon composite FePSe ₃ /C nanosheet material through the electrochemical test of the carbon composite FePSe ₃ /C nanosheet material, thus indicating that the carbon composite FePSe 3 /C nanosheet material The composite FePSe ₃ /C nanosheet material is an excellent cathode material for alkali metal ions, especially for sodium ion batteries.

Description

an alkali metal ion battery

technical field

The invention relates to the technical field of battery materials, in particular to an alkali metal ion battery.

Background technique

The development of effective electrochemical energy storage and conversion methods is a problem that must be solved in today's environment-friendly society. Since their commercialization, lithium-ion batteries have been used in a variety of fields including mobile electronic devices and power vehicles. However, lithium-ion batteries also have their own shortcomings, especially their low global reserves, the global element abundance is only 20ppm, and the main mineral deposits are concentrated in South America, which has led to the high price of lithium. Due to the fact that the global reserves of sodium are as high as 2.4% and it is evenly distributed worldwide, it has a cheaper price. At the same time, due to the similar principle, it can often be used as a material for lithium-ion batteries and can also be used as sodium-ion batteries. In order to solve the problems of limited lithium resources and price, sodium-ion batteries have gradually entered the field of view of researchers and are regarded as an alternative solution.

Layered transition metal phosphorus-selenide compounds have been shown to have broad application prospects in the field of energy conversion and storage in recent years, especially their special layered structure makes them suitable for use in ion batteries. Therefore, the improvement of layered transition metal phosphorus selenide compounds is expected to further improve the performance of alkali metal ion batteries.

SUMMARY OF THE INVENTION

The technical problem solved by the present invention is to provide an alkali metal ion battery, and the alkali metal ion battery provided by the present application has high specific capacity, excellent rate performance and good durability performance, especially for sodium ion battery, it has higher The sodium storage stability and cycling stability.

In view of this, the present application provides an alkali metal ion battery, including a positive electrode, a negative electrode and an electrolyte, the material of the positive electrode includes a carbon-composite iron phosphorus selenium compound, a conductive agent and a binder, and the carbon-composite iron The phosphorus-selenium compound includes a carbon layer and an iron-phosphorus-selenide compound, and the carbon layer coats the surface of the iron-phosphorus-selenide compound.

Preferably, the preparation method of the carbon composite iron phosphorus selenium compound is as follows:

The ferrocene, phosphorus and selenium are mixed in a molar ratio of 1:1:3 and then reacted in a vacuum airtight environment to obtain a carbon composite iron phosphorus selenium compound.

Preferably, the phosphorus is red phosphorus.

Preferably, the process of the reaction is specifically:

The ferrocene, phosphorus and selenium are placed in a quartz tube, vacuumed and sealed, and the sealed quartz tube is placed in a muffle furnace at a rate of 1 to 10 °C/min to 600 to 900 °C to react for at least 30 minutes.

Preferably, the inside of the quartz tube is kept in a vacuum state.

Preferably, after the reaction, it also includes:

The obtained powder is ground, washed, centrifuged, and finally dried.

Preferably, the washing liquid for washing is ethanol, and the drying is carried out in a vacuum drying oven.

Preferably, the thickness of the carbon layer is 3-4 nm, and the thickness of the carbon-complexed iron-phosphorus-selenium compound is 10-20 nm.

Preferably, the mass ratio of the carbon composite iron-phosphorus-selenium compound, the conductive agent and the binder is (6-8):(1-2):(1-2).

Preferably, the alkali metal ion battery is a sodium ion battery.

The application provides an alkali metal ion battery, which includes a positive electrode, a negative electrode and an electrolyte, wherein the material of the positive electrode includes a carbon-composite iron phosphorus selenium compound, a conductive agent and a binder, and the carbon composite iron phosphorus selenium compound The compound includes a carbon layer and an iron phosphorus selenide compound, and the carbon layer coats the surface of the iron phosphorus selenide compound. The iron phosphorus selenide compound in the carbon composite iron phosphorus selenide compound provided by the present application is a layered two-dimensional structure material maintained by van der Waals force, and the space between the material layers provides alkali metal ions (Li ⁺ , Na ⁺ ) insertion space, after testing, the material can insert and store more ions when used as the positive electrode of metal ion batteries, and has a higher specific capacity than the current commercial alkali metal ion battery positive electrode; It has a larger surface area and can attach more metal ions; at the same time, due to the insertion of alkali metal ions, the interlayer spacing will become larger, so that the volume of the material expands, and the introduction of carbon coating can provide carbon The frame can reduce the effect of the volume expansion of the material, and can also increase the electrical conductivity of the material, thereby improving the durable performance of the material.

Description of drawings

1 is a transmission electron micrograph (TEM) (a) and a scanning electron micrograph (SEM) (b) of the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1;

Fig. 2 is a high-resolution transmission electron micrograph (HRTEM) (a), a fast Fourier transform pattern (FFT) (b) and a high-resolution transmission electron micrograph (HRTEM) of the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1. Element-containing high-angle annular dark field image (HAADF-STEM) and Mapping photo (c);

Fig. 3 is the X-ray diffraction pattern (XRD) (a) of the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1, and the (002) peak X-ray diffraction pattern (XRD) (b) of C;

4 is the X-ray photoelectron of Fe 2p(a), P2p(b), Se 3d(c), C 1s(d) elements in the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1 Energy spectrum (XPS) and score (e);

5 is the Raman spectrum (a) and the Raman spectrum (b) of C of the carbon composite iron phosphorus selenide compound FePSe ₃ /C nanomaterial FePSe ₃ prepared in Example 1;

6 is a performance curve diagram of the sodium-ion battery assembled with the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1 under a current density of 50 mA g ⁻¹ , which is stably cycled for 50 cycles;

Fig. 7 is the rate performance curve diagram of the sodium ion battery of the carbon composite iron phosphorus selenide compound FePSe ₃ /C nanomaterial prepared in Example 1;

8 is a performance curve diagram of the sodium-ion battery assembled by the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1 under a current density of 1Ag ⁻¹ , which is stably cycled for 200 cycles;

9 is a performance curve diagram of the lithium ion battery assembled with the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1 under a current density of 50 mAg ^-1 for 50 cycles of stable cycling;

10 is a graph showing the rate performance of a lithium ion battery of the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1;

Figure 11 is the performance curve of the lithium ion battery assembled with the carbon composite FePSe ₃ /C nanomaterial prepared in Example 1 under the current density of 1Ag ^-1 (50mAg ^-1 activation for the first three cycles) for 100 cycles .

Detailed ways

In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with the examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

In order to widen the selectivity of the positive electrode material of the alkali metal ion battery and improve the performance of the alkali metal ion battery, the embodiment of the present invention discloses an alkali metal ion battery, which includes a positive electrode, a negative electrode and an electrolyte, and the material of the positive electrode includes carbon composite iron phosphorus A selenium compound, a conductive agent and a binder, the carbon composite iron-phosphorus-selenium compound comprises a carbon layer and an iron-phosphorus-selenide compound, and the carbon layer coats the surface of the iron-phosphorus-selenium compound.

For the alkali metal ion battery provided in this application, it includes a positive electrode, a negative electrode and an electrolyte, wherein the negative electrode and the electrolyte are well known to those skilled in the art, and this application is not particularly limited; exemplarily, for a sodium ion battery, The negative electrode is a metal sodium sheet, and the electrolyte is selected from sodium hexafluorophosphate dissolved in diethylene glycol dimethyl ether; for lithium ion batteries, the negative electrode is a metal lithium sheet, and the electrolyte is selected from ethylene carbonate dissolved in a volume ratio of 1:1 Lithium hexafluorophosphate ester and diethyl carbonate.

Therefore, the material of the positive electrode of the alkali metal ion battery is specifically selected from the carbon composite iron phosphorus selenium compound, the conductive agent and the binder, and the conductive agent and the binder are materials well known to those skilled in the art. The conductive agent is selected from Ketjen Black, and the binder is selected from PVDF. In the present application, the mass ratio of the carbon composite iron-phosphorus-selenium compound, the conductive agent and the binder is (6-8):(1-2):(1-2), more specifically , the mass ratio of the carbon composite iron-phosphorus-selenium compound, the conductive agent and the binder is 8:1:1, 7:1.5:1.5, 7:1:2 or 6:2:2. The proportion of the binder is preferably not less than 10% of the material of the positive electrode to ensure that the material can adhere to the current collector, too much binder will affect the cycle performance of the battery; the carbon composite iron phosphorus The ratio of the selenium compound within the above range can increase the effective load to increase the energy density of the battery. The active material of the material of the positive electrode of the present application is specifically a carbon-composite iron phosphorus selenide compound, which is composed of a carbon layer and an iron phosphorus selenide compound, and the carbon layer coats the surface of the iron phosphorus selenide compound. In the carbon composite iron phosphorus selenide compound, the thickness of the carbon layer is 3˜4 nm, and the thickness of the carbon composite iron phosphorus selenide compound is 10 nm to 20 nm.

More specifically, the preparation method of the carbon composite iron phosphorus selenium compound is specifically:

The ferrocene, phosphorus and selenium are mixed in a molar ratio of 1:1:3 and then reacted in a vacuum airtight environment to obtain a carbon composite iron phosphorus selenium compound.

The carbon composite iron phosphorus selenium compound prepared by the method has high crystallinity and uniform carbon coating on the surface, and has a good practical prospect. Specifically, the embodiment of the present invention discloses a preparation method of a carbon composite iron phosphorus selenium compound, comprising the following steps:

The ferrocene, phosphorus and selenium are mixed in a molar ratio of 1:1:3 and then reacted in a vacuum airtight environment to obtain a carbon composite iron phosphorus selenium compound.

In the above-mentioned process of preparing the carbon composite iron phosphorus selenium compound, the technical difficulty of the preparation is that it needs to be carried out in a high pressure, high temperature and oxygen-free environment, so as to ensure that the carbon composite iron phosphorus selenium compound can be synthesized in one step and in a short time.

In this application, the phosphorus is specifically selected from red phosphorus, the selenium is specifically selected from selenium materials well known to those skilled in the art, and more specifically, the selenium is selected from selenium powder.

Specifically, the process of preparing the carbon composite iron-phosphorus-selenium compound described in this application is as follows:

The ferrocene, red phosphorus and selenium powder are placed in a quartz tube, and the vacuum-sealed quartz tube is placed in a muffle furnace at a rate of 1 to 10 °C/min to 600 to 900 °C to react for at least 30 minutes.

More specifically, the above-mentioned quartz tube is a vacuum-tight quartz tube, so that the reaction can be carried out in a high-pressure, oxygen-free environment.

In the above process, the organometallic precursor ferrocene is thermally decomposed and gas is generated to increase the pressure in the quartz tube, and the iron element reacts with the sublimated red phosphorus and liquefied selenium element to form a flake-shaped iron phosphorus selenium compound compound. The organic gas generated during the decomposition of ferrocene is gradually carbonized on the surface of the iron-phosphorus-selenide compound, realizing one-step synthesis and carbon coating.

The above-mentioned heating rate may specifically be 2°C/min, 3°C/min, 4°C/min, 5°C/min, 6°C/min, 7°C/min, 8°C/min or 9°C/min; The temperature can be specifically 650°C, 680°C, 700°C, 720°C, 760°C, 780°C, 820°C, 840°C, 880°C or 890°C; the reaction time can be specifically 1h, 1.5h, 2h, 3h , 5h, 6h, 7.5h, 8.5h, 10h, 12h, 13.5h, 14h, 15h, 18h, 20h, 22h, 23h or 26h.

After the above reaction, the obtained powder is ground, washed, centrifuged, and finally dried to obtain a carbon-complexed iron-phosphorus-selenium compound.

The invention greatly shortens the preparation time through a simple one-step vacuum sealing tube synthesis method, and can obtain carbon composite iron-phosphorus-selenium compound nanomaterials with high crystallinity and high purity.

In the alkali metal ion battery provided by the present application, a carbon composite iron phosphorus selenium compound is introduced into the material of the positive electrode. Due to the introduction of the carbon coating means, the conductivity of the material can be enhanced, and the volume expansion of the material can be limited, thereby enhancing the The stability of carbon-complexed iron phosphorus selenide compounds in alkali metal ion batteries, especially sodium ion battery applications.

In order to further understand the present invention, the alkali metal ion battery provided by the present invention will be described in detail below with reference to the examples, and the protection scope of the present invention is not limited by the following examples.

Example 1

Take 0.6 mmol (0.112 g) ferrocene [Fe(C ₅ H ₅ ) ₂ ], 0.6 mmol (0.019 g) red phosphorus powder [P] and 1.8 mmol (0.142 g) selenium elemental powder [Se] in an inner diameter of In the 8mm quartz tube, seal the quartz tube while maintaining the vacuum state in the tube; place the sealed quartz tube obliquely in the muffle furnace, and keep the reactants at the bottom of the quartz tube; in the muffle furnace, the speed is 2 °C/min. The temperature was raised to 600 °C and kept at 600 °C for more than 30 minutes; after natural cooling, the quartz tube was opened to obtain a black powder sample. After grinding, the product was washed several times with ethanol solution, and finally centrifuged and placed in a vacuum drying box. After drying, the final product carbon composite iron phosphorus selenide compound FePSe ₃ /C nanomaterial is obtained.

From the transmission electron micrograph (TEM) (Fig. 1a) and the scanning electron microscope (SEM) (Fig. 1b), it can be seen that the FePSe ₃ /C nanomaterial of the iron phosphorus selenide compound exhibits an irregular sheet-like structure, and the thickness varies with the reaction The time was changed, when the reaction time was 24 hours, the thickness was about 15 nm.

The FePSe ₃ /C was calibrated in high-resolution transmission electron micrographs (HRTEM) (Fig. 2a), where the lattice fringes of 0.180 nm and 0.181 nm can accurately correspond to (11-9) and (300 of FePSe ₃ ) ) crystal plane, the more obvious 0.335nm lattice fringes at the edge of the material can accurately correspond to the surface carbon-coated C(002) crystal plane; perform fast Fourier transform (FFT) on the selected area in the high-resolution photo , the results are shown in Figure 2b, which is in line with the characteristics of the pure phase FePSe ₃ nanomaterial rhombohedral system; Figure 2c shows the high-angle annular dark field image (HAADF-STEM) of the sample and the three basic elements Fe, P and Se, respectively. The Mapping photo shows that the C element is not only uniformly distributed in the interior of the material nanosheets with Fe, P and Se, but also appears alone at the edge of the material nanosheets, which proves the successful coating of the carbon material.

FePSe ₃ nanomaterials belong to the R-3 space group, and its X-ray diffraction pattern (XRD) is shown in Fig. 3a, where the positions are at 13.4°, 24.3°, 27.0°, 28.4°, 31.6°, 34.2°, 35.7°, 39.6° The 2θ peaks at °, 50.3°, 50.6°, 52.3°, 55.6°, 58.0°, 60.6°, 63.6°, 65.9°, 74.2°, 78.3° and 78.2° can precisely correspond to the (003), (104), (006), (110), (11-3), (202), (107), (11-6), (300), (11-9), (033), (0012), (036), (22-3), (11-12), (22-6), (22-9), (0312) and (11-15) diffraction crystal planes (JCPDS 01-089-1415); in Between 25-28° (Fig. 3b), the 2θ peak at 26.6° corresponds to the (002) peak of carbon, which further proves the existence of carbon coating; no impurity peaks that do not belong to the target product are observed in the figure, It shows that FePSe ₃ /C prepared by the simple one-step method proposed in this experiment is pure phase and has high crystallinity.

X-ray photoelectron spectroscopy (XPS) reflects the composition of elements in the material and the chemical state of each element; for FePSe ₃ /C material (Fig. 4a-e), in the fine spectrum of Fe 2p (Fig. 4a), The characteristic peaks belonging to Fe ²⁺ at the binding energies of 710.50eV and 723.9eV, and the characteristic peaks originating from the higher oxidation state Fe ³⁺ at the binding energies of 713.2eV and 727.4eV can be observed respectively; in Fig. 4b, P The fine XPS spectrum of 2p consists of the P 2p _3/2 peak at 131.6 eV, the P 2p _1/2 peak at 132.5 eV, and the oxidation peak corresponding to P ₄ O ₁₀ at 134.1 eV; Fig. 4c is composed of the P 2p 3/2 peak at 54.6 eV It is composed of the Se 3d _5/2 peak and the Se 3d _3/2 peak at 56.1 eV. It is worth noting that the 3p peak of Fe also appears at 55.5 eV at the same time; in Figure 4d, the 1s peak of C is located at 284.8, At 285.9 and 288.5 eV, corresponding to the presence of CC, C=O and CO, respectively; finally Figure 4e is the XPS total spectrum of FePSe ₃ /C material.

Raman spectroscopy was also used to study the structure of this compound; as can be seen from Figure 5a, there are 2 A _1g and 2 E _g modes, respectively, of which the 2 A _1g modes are located at wavenumbers 214.4 and 487.7, respectively cm ^-1 , the two E _g modes are located at 147.0 and 167.1 cm ^-1 , respectively, corresponding to the [P ₂ Se ₆ ] unit in the FePSe ₃ material; the Raman characteristic spectrum of carbon can be seen in Fig. 5b, at 1350 The D band and _G band of carbon can be seen at 1590 cm -1 and 1590 cm ^-1 respectively, and the peak intensity ID / _IG of both is 0.92, which proves the existence of carbon in the material.

Example 2 Na-ion battery performance of FePSe ₃ /C material

The FePSe ₃ /C composite material prepared in Example 1 was used to assemble a coin-type half cell: the ratio of FePSe ₃ /C material, Ketjen Black and PVDF in the cathode slurry of the half cell was 8:1:1 or 7:1.5:1.5 , the separator is Whatman GF/D glass fiber, and the electrolyte is NaPF ₆ (concentration 1.0M) dissolved in diethylene glycol dimethyl ether. On the blue electricity test system, the charge and discharge cycles of the battery under constant current can be completed respectively. And the rate performance test under a series of currents, in which the charging and discharging voltage range is 0.8-2.2V.

FePSe ₃ /C nanomaterials exhibited excellent rate capability at a range of current densities. When the current density was 50 mA g ^-1 (Fig. 6), the discharge specific capacity of the material after 50 charge-discharge cycles It is still as high as 182.7mAh g ^-1 , and the Coulomb efficiency can be kept above 99.8% all the time.

The rate performance of the carbon composite FePSe ₃ /C nanosheet material for sodium storage prepared in Example 1 is shown in Figure 7. The current density is gradually increased from 50mA g ^-1 to 200, 500, 1000, 2000, At 3000 and maximum 5000mA g ^-1 , the discharge specific capacity can still be maintained at 252, 213, 190, 172, 153, 131, 111, and 95mA hg ^-1 and remain stable, when the current density is reduced to 1000mA g ^-1 and the initial 50mA g ^-1 , the specific capacity of FePSe ₃ /C can be recovered to 142 and 186mAh g ^-1 , respectively, which indicates that the material has excellent sodium storage stability under different current densities.

Figure 8 shows that the carbon composite FePSe ₃ /C nanosheet material has experienced a long-time cycle of 200 cycles at a current density of 1A g ^-1 , and the discharge specific capacity of this material is still as high as 142mAh g ^-1 , which proves that The material exhibits excellent sodium storage stability at different current densities.

It is confirmed by the above discussion and analysis that the carbon composite FePSe ₃ /C nanosheet material synthesized by the present invention has high specific capacity, excellent rate performance and good durability, and is a very potential sodium Ion battery anode material.

Example 3 Li-ion battery performance of FePSe ₃ /C material

Using the FePSe ₃ /C composite material prepared in Example 1 to assemble a coin-type half cell: In the cathode slurry of the half cell, the ratio of FePSe ₃ /C material, Ketjen black and PVDF is 8:1:1 or 7:1.5: 1.5, the diaphragm is celgard 2400, and the electrolyte is LiPF6 (concentration 1.0M) dissolved in ₁ :1 ethylene carbonate:diethyl carbonate. On the blue power test system, the charge-discharge cycle of the battery under constant current and the rate performance test under a series of currents can be completed respectively. The charge-discharge voltage range is 1.2-2.6V.

Fig. 9 is the performance curve of the lithium ion battery assembled by carbon composite FePSe ₃ /C nanomaterials under 50mA g ^-1 current density for 50 cycles; Fig. 10 is the carbon composite FePSe compound FePSe The rate performance curve of Li-ion battery of ₃ /C nanomaterials; Figure 11 is the lithium-ion battery assembled by carbon composite FePSe ₃ /C nanomaterials at 1A g ^-1 (50mAg ^-1 activation for the first three circles) Performance curves for 100 cycles at current density. It can be seen from the above figure that the FePSe ₃ /C nanomaterials exhibit excellent cycle performance under a range of current densities. When the current density is 50mAg ^-1 , the discharge specific capacity of the material after 50 charge-discharge cycles There is still 308mAh g ^-1 , and the coulombic efficiency can be kept above 98.4% all the time. When the current density was gradually increased from 50 mA g ^-1 to 100, 200 and 500 mA g ^-1 at the maximum, the discharge specific capacity could still be maintained at 411, 348, 310 and 202 mA hg ^-1 and remained stable, respectively. After 100 cycles at a higher current density of 1A g ^-1 , the discharge specific capacity of the material remains 101mAh g ^-1 , which proves that the material has excellent lithium storage stability under different current densities. performance.

The descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

The above description of the disclosed embodiments enables any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The alkali metal ion battery comprises a positive electrode, a negative electrode and electrolyte, and is characterized in that the positive electrode is made of carbon-compounded iron-phosphorus-selenium compounds, a conductive agent and a binder, the carbon-compounded iron-phosphorus-selenium compounds comprise a carbon layer and the iron-phosphorus-selenium compounds, and the carbon layer is coated on the surface of the iron-phosphorus-selenium compounds.

2. The alkali metal ion battery of claim 1, wherein the carbon-complexed iron-phosphorus-selenium compound is prepared by a method comprising:

mixing ferrocene, phosphorus and selenium according to the molar ratio of 1:1:3, and reacting in a vacuum closed environment to obtain the carbon-compounded iron-phosphorus-selenium compound.

3. The alkali metal ion battery of claim 2, wherein the phosphorus is red phosphorus.

4. The alkali metal ion battery of claim 2, wherein the reaction is specifically carried out by:

and placing ferrocene, phosphorus and selenium in a quartz tube, vacuumizing and sealing the quartz tube, and placing the sealed quartz tube in a muffle furnace to react for at least 30min at a speed of 1-10 ℃/min and at a temperature of 600-900 ℃.

5. The alkali metal ion battery of claim 4, wherein the quartz tube is maintained in a vacuum state.

6. The alkali metal ion battery of claim 2 or 4, further comprising, after the reacting:

the obtained powder is ground, washed, centrifuged and dried.

7. The alkali metal ion battery of claim 6, wherein the washed washing solution is ethanol and the drying is performed in a vacuum drying oven.

8. The alkali metal ion battery as claimed in claim 1, wherein the carbon layer has a thickness of 3 to 4nm and the carbon-complexed iron-phosphorus-selenium compound has a thickness of 10 to 20 nm.

9. The alkali metal ion battery as claimed in claim 1, wherein the mass ratio of the carbon-composited iron-phosphorus-selenium compound to the conductive agent to the binder is (6-8): (1-2): (1-2).

10. The alkali metal ion battery according to any one of claims 1 to 9, wherein the alkali metal ion battery is a sodium ion battery.

Images