A porous manganese-based lithium ion sieve precursor, a preparation method and application thereof

Abstract

The application provides a porous manganese-based lithium ion sieve precursor, a preparation method and application thereof, and belongs to the technical field of lithium ion sieve preparation. The method comprises the following steps: pyrolyzing a manganese salt solution into a manganese-oxygen mixture through a spray pyrolysis method; sintering the manganese-oxygen mixture at a low temperature in an air atmosphere to form a nano-porous precursor Mn2O3; mixing and grinding the nano-porous precursor Mn2O3 with a lithium salt according to a set ratio, and obtaining a porous manganese-based lithium ion sieve precursor Li4Mn5O 12 after solid-phase calcination. 12 After being delithiated in an acid and dried, a lithium ion sieve H4Mn5O 12 is obtained. The application synthesizes the nano-porous precursor Mn2O3 by using a spray pyrolysis method, combines low-temperature sintering of two solid-phase processes, and makes the Li4Mn5O 12 lithium ion sieve precursor keep a porous morphology, has the characteristics of a large specific surface area and uniform particle size, is beneficial to the processes of acid delithiation and ion sieve adsorption of lithium, and improves the adsorption rate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion sieve preparation, and particularly relates to a porous manganese-based lithium ion sieve precursor and a preparation method and application thereof. BACKGROUND

[0002] Lithium has unique and excellent physicochemical properties and is widely used in energy, aerospace, metallurgy, medical treatment and other fields and is known as "white oil". The raw materials for preparing lithium in industry mainly come from salt lake brine and lithium ore, and the lithium reserves of the salt lake brine are much greater than those of the lithium ore. However, compared with lithium ore extraction, the salt lake brine extraction is more difficult and has higher cost. The lithium ion sieve adsorption method is a green and environmentally friendly lithium extraction method with relatively low cost, and the lithium ion sieve has good selectivity to lithium and can improve the extraction efficiency of lithium in the salt lake brine.

[0003] Since the lithium ion sieve is converted from Li + , the quality of the lithium ion sieve is directly related to the quality of the lithium ion sieve precursor, and the synthesis of the lithium ion sieve precursor is the key to the whole lithium ion sieve preparation process and has various methods. 12 Li4Mn5O 12 is one of common manganese-based lithium ion sieve precursors, and has low Mn dissolution loss and good stability due to the high valence of Mn in adsorption practice. At present, the methods for synthesizing Li4Mn5O 12 The particles prepared by the methods have rod-like, spherical and sheet-like morphologies. The sheet-like and rod-like Li4Mn5O 12 particles have small specific surface areas and low adsorption rates; the spherical particles have large specific surface areas and good lithium adsorption performance, but the current synthesis method is complex, and the formed particles are prone to agglomeration, have large and uneven particle sizes, and the subsequent lithium ion sieve has poor performance. SUMMARY

[0004] In view of this, the present application aims to provide a porous manganese-based lithium ion sieve precursor and a preparation method and application thereof, and aims to solve at least one technical problem in the background art.

[0005] The present application is implemented in the following manner:

[0006] The first aspect of the present application provides a preparation method of a porous manganese-based lithium ion sieve precursor, comprising the following steps:

[0007] pyrolyzing the manganese salt solution into a manganese-oxygen mixture by a spray pyrolysis method;

[0008] sintering the manganese-oxygen mixture at low temperature in an air atmosphere to form a nano-porous precursor Mn2O3;

[0009] The nanoporous precursor Mn2O3 is mixed with lithium salt according to a set ratio, and after solid-phase calcination, a porous lithium-rich manganese oxide Li4Mn5O 12 , that is, a porous manganese-based lithium ion sieve precursor;

[0010] In the spray pyrolysis method, oxygen is used as the carrier gas; and the lithium salt is used in an amount exceeding the theoretical amount;

[0011] Further, the spray pyrolysis method is performed at a temperature of 650 DEG C to 950 DEG C, a pyrolysis time of 5 h to 10 h, and a gas flow rate of 2 L / min to 8 L / min.

[0012] Further, the low-temperature sintering is performed at a temperature of 200 DEG C to 500 DEG C and a time of 2 h to 5 h.

[0013] Further, the solid-phase calcination is performed at a temperature of 300 DEG C to 700 DEG C, a calcination time of 10 h to 24 h, and in an oxygen or air atmosphere.

[0014] Further, the manganese salt solution is at least one of a manganese chloride solution, a manganese sulfate solution, a manganese acetate solution, and a manganese nitrate solution.

[0015] Further, the lithium salt is at least one of lithium chloride, lithium hydroxide, lithium nitrate, and lithium carbonate; and the nanoporous precursor Mn2O3 and the lithium salt are used in a molar ratio of Mn:Li = 5:4 to 4.1.

[0016] The second application of the application provides a porous manganese-based lithium ion sieve precursor, which is prepared by the preparation method.

[0017] The third aspect of the application provides an application of the porous manganese-based lithium ion sieve precursor, which is used for preparing a porous manganese-based lithium ion sieve. 12 The lithium ion sieve H4Mn5O is obtained by delithiation in an acid and drying. 12 .

[0018] Further, the acid is formic acid, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, or sulfurous acid, the acid concentration is 0.1 mol / L to 1 mol / L, and the acid delithiation time is 0.5 h to 3 h.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. The nanoporous precursor Mn2O3 is synthesized by the spray pyrolysis method, and the low-temperature sintering in the two solid-phase processes, so that the Li4Mn5O 12 ion sieve precursor maintains a porous morphology, has a large specific surface area and a uniform particle size, is beneficial to the acid delithiation and ion sieve lithium adsorption processes, and improves the adsorption rate.

[0021] 2、The synthetic Li4Mn5O 12 The ion sieve precursor has high-valence Mn, reduces Mn loss in an acid washing process, and has good cycle performance.

[0022] 3、The synthetic method provided by the application has the advantages of short flow, simple operation, low cost, environmental protection, and the like, and has considerable industrial application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A flowchart for preparing the lithium ion sieve according to the application;

[0024] Figure 2 An XRD pattern of the precursor Mn2O3 prepared in Examples 1 to 5 of the application;

[0025] Figure 3 An SEM pattern of the Mn2O3 prepared in Example 2 of the application;

[0026] Figure 4 An XRD pattern of the porous lithium-rich manganese oxide Li4Mn5O 12 prepared in Examples 1 to 5 of the application. DETAILED DESCRIPTION

[0027] In order to make the objects, technical solutions and advantages of the application clearer, the application is further described in detail below with reference to examples. It should be understood that the specific implementation examples described herein are only used to explain the application and do not limit the application.

[0028] A preparation method of a porous manganese-based lithium ion sieve precursor, comprising the following steps:

[0029] S1, pyrolyzing a manganese salt solution into a manganese-oxygen mixture by a spray pyrolysis method;

[0030] Dissolving manganese chloride, manganese sulfate, manganese acetate, manganese nitrate and the like into water to form a manganese salt solution;

[0031] Placing the manganese salt solution in a spray pyrolysis furnace, and passing oxygen at a gas flow rate of 2-8 L / min, heating to 650-950℃, and keeping the temperature for 5-10 h, to pyrolyze the manganese salt into a manganese-oxygen mixture;

[0032] The pyrolysis temperature is selected to be 650-950℃, which can form a larger proportion of Mn2O3, and on the other hand, Mn2O3 can remain stable in this temperature range; the specific temperature selection in the following examples can be adjusted according to the type of manganese salt.

[0033] S2, sintering the manganese-oxygen mixture at 200-500℃ under air atmosphere for 2-5h to form a nanoporous precursor Mn2O3;

[0034] S3, mixing and grinding the nanoporous precursor Mn2O3 with lithium salt according to a set ratio, and obtaining a porous lithium-rich manganese oxide Li4Mn5O 12 ,

[0035] The lithium salt is at least one of lithium chloride, lithium hydroxide, lithium nitrate, and lithium carbonate, and since the lithium salt is volatile during high-temperature calcination, the amount of lithium salt is more than the theoretical amount, specifically, according to the molar ratio, Mn:Li in the nanoporous precursor Mn2O3 and the lithium salt is 5:4-4.1;

[0036] The solid-phase calcination temperature is 300-700℃, the calcination time is 10-24h, the solid-phase calcination atmosphere is oxygen or air, and the product obtained after calcination is the porous manganese-based lithium ion sieve precursor.

[0037] The manganese-based lithium ion sieve precursor prepared by the above method maintains a porous morphology, has a large specific surface area and uniform particle size, and these morphological characteristics are beneficial to the processes of acid leaching lithium and ion sieve adsorbing lithium, thereby improving the adsorption rate.

[0038] Based on the above porous manganese-based lithium ion sieve precursor, a lithium ion sieve is prepared, and the porous lithium-rich manganese oxide Li4Mn5O 12 is leached in acid to obtain a lithium ion sieve H4Mn5O 12 ; the acid is formic acid, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, or sulfurous acid, the acid concentration is 0.1-1mol / L, and the acid leaching lithium time is 0.5-3h.

[0039] Example 1

[0040] A preparation method of a porous manganese-based lithium ion sieve, the flowchart of which is shown in Figure 1 , and the steps are as follows:

[0041] (1) 500mL of a MnCl2 solution with a concentration of 0.6mol / L is prepared, and the MnCl2 solution is placed in a three-head atomizer for pyrolysis under the condition of an oxygen flow rate of 2L / min, the pyrolysis temperature is 800℃, and the pyrolysis time is 6h, to obtain a manganese oxide;

[0042] (2) the manganese oxide is placed in a tube furnace and heated to 450℃ at a heating rate of 5℃ / min under air atmosphere, and kept at 450℃ for 4h, and after natural cooling, a precursor Mn2O3 is obtained, and the XRD characterization result is shown in Figure 2 , the phase is consistent with the characteristic spectrum of Mn2O3, and the precursor particles are loose and porous;

[0043] (3) Mn2O3 and LiOH·H2O were mixed and ground, and the stoichiometric ratio was maintained at Mn:Li=5:4.05 according to the molar ratio. The mixture was heated to 500℃ under an oxygen atmosphere and kept for 18h to obtain Li4Mn5O 12 As a porous manganese-based lithium ion sieve precursor, the XRD characterization results are as follows Figure 4 ;

[0044] (4) Li4Mn5O 12 The ion sieve precursor was washed with 0.15 mol / L hydrochloric acid for 1 h to obtain H4Mn5O 12 After washing and drying, a porous manganese-based lithium ion sieve is obtained.

[0045] Example 2

[0046] A method for preparing a porous manganese-based lithium ion sieve, the process of which is as follows Figure 1 As shown, the steps are as follows:

[0047] (1) 500 mL of a 0.6 mol / L MnCl2 solution was prepared and pyrolyzed in a three-head atomizer at an oxygen flow rate of 4 L / min at a temperature of 800°C for 6 h to obtain manganese oxide.

[0048] (2) Manganese oxide was placed in a tube furnace and heated to 450°C at a heating rate of 5°C / min under air atmosphere and kept at this temperature for 4 hours. After natural cooling, the precursor Mn2O3 was obtained. The XRD characterization results are shown in Fig. Figure 2 The physical phase conforms to the characteristic spectrum of Mn2O3, and its SEM image is as follows Figure 3 As shown, Figure 3 The scale bars in Figures A and B are 1 μm and 10 μm, respectively, and the precursor particles are loose and porous;

[0049] (3) Mn2O3 and LiCl were mixed and ground, and the stoichiometric ratio was maintained at Mn:Li=5:4.1 according to the molar ratio. The temperature was raised to 500℃ under an oxygen atmosphere and kept for 18h to obtain Li4Mn5O 12 As the XRD characterization results of porous manganese-based lithium ion sieve precursor are as follows Figure 4 ;

[0050] (4) Li4Mn5O 12 The ion sieve precursor was washed with 0.15 mol / L hydrochloric acid for 1 h to obtain H4Mn5O 12 After washing and drying, a porous manganese-based lithium ion sieve is obtained.

[0051] Example 3

[0052] A method for preparing a porous manganese-based lithium ion sieve, the process of which is as follows Figure 1 As shown, the steps are as follows:

[0053] (1) Configuration 500 mL of MnCl2 solution with a concentration of 0.6 mol / L, under the condition of oxygen flow rate of 6 L / min, the MnCl2 solution is placed in a three-head atomizer for pyrolysis, the pyrolysis temperature is 800℃, the pyrolysis time is 6h, and manganese oxide is obtained;

[0054] (2) The manganese oxide is placed in a tube furnace and heated to 450℃ at a heating rate of 5℃ / min under air atmosphere, and after natural cooling, Mn2O3 is obtained, and the XRD characterization result is as shown in Figure 2 , the phase is consistent with the characteristic spectrum of Mn2O3, and the precursor particles are loose and porous;

[0055] (3) Mn2O3 and Li2NO3 are mixed and ground, the molar ratio is maintained as Mn:Li=5:4.07, and Li4Mn5O 12 is obtained by heating to 500℃ under oxygen atmosphere for 18h as a porous manganese-based lithium ion sieve precursor, and the XRD characterization result is as shown in Figure 4 ;

[0056] (4) Li4Mn5O 12 is washed with 0.15 mol / L nitric acid for 1h to obtain H4Mn5O 12 , and the porous manganese-based lithium ion sieve is obtained after cleaning and drying.

[0057] Example 4

[0058] A method for preparing a porous manganese-based lithium ion sieve, the flowchart is as shown in Figure 1 , and the steps are as follows:

[0059] (1) Configuration 500 mL of MnSO4 solution with a concentration of 0.6 mol / L, under the condition of oxygen flow rate of 4 L / min, the MnSO4 solution is placed in a three-head atomizer for pyrolysis, the pyrolysis temperature is 950℃, the pyrolysis time is 8h, and manganese oxide is obtained;

[0060] (2) The manganese oxide is placed in a tube furnace and heated to 400℃ at a heating rate of 5℃ / min under air atmosphere, and after natural cooling, loose and porous precursor Mn2O3 particles are obtained, and the XRD characterization result is as shown in Figure 2 ;

[0061] (3) Mn2O3 and Li2CO3 are mixed and ground, the molar ratio is maintained as Mn:Li=5:4.1, and Li4Mn5O 12 is obtained by heating to 500℃ under oxygen atmosphere for 20h as a porous manganese-based lithium ion sieve precursor, and the XRD characterization result is as shown in Figure 4 ;

[0062] (4) washing the Li4Mn5O 12 The ion sieve precursor is washed with 1 mol / L formic acid for 3 h to obtain H4Mn5O 12 After washing and drying, the porous manganese-based lithium ion sieve is obtained.

[0063] Example 5

[0064] A method for preparing a porous manganese-based lithium ion sieve, the flowchart of which is shown in Figure 1 The steps are as follows:

[0065] (1) A 500 mL Mn(Ac)2 solution with a concentration of 0.6 mol / L is prepared, and the Mn(Ac)2 solution is placed in a three-head atomizer for pyrolysis under the condition of an oxygen flow rate of 4 L / min, the pyrolysis temperature is 650 ℃, and the pyrolysis time is 5 h to obtain manganese oxide;

[0066] (2) The manganese oxide is placed in a tube furnace and heated to 450 ℃ at a heating rate of 5 ℃ / min under an air atmosphere, and then kept at 450 ℃ for 3 h, and after natural cooling, loose and porous precursor Mn2O3 particles are obtained, and the XRD characterization results are as shown in Figure 2 ;

[0067] (3) Mn2O3 and LiOH·H2O are mixed and ground, and the molar ratio is maintained at Mn:Li = 5:4 in stoichiometric ratio, and then heated to 300 ℃ under an oxygen atmosphere and kept for 15 h to obtain Li4Mn5O 12 as a porous manganese-based lithium ion sieve precursor, and the XRD characterization results are as shown in Figure 4 ;

[0068] (4) washing the Li4Mn5O 12 The ion sieve precursor is washed with 0.5 mol / L phosphoric acid for 3 h to obtain H4Mn5O 12 After washing and drying, the porous manganese-based lithium ion sieve is obtained.

[0069] Comparative Example 1

[0070] The manganese-based lithium ion sieve is prepared in this comparative example, and the only difference between the steps and Example 2 is step (1);

[0071] Step (1) of this comparative example is: MnCl2 solid is placed in a pyrolysis furnace for pyrolysis, the pyrolysis temperature is 800 ℃, and the pyrolysis time is 6 h. The remaining steps and parameters are the same as those of Example 2.

[0072] The lithium ion sieve precursors and ion sieves prepared in Examples 1 to 5 and Comparative Example 1 are tested for performance, including:

[0073] 1. Characterization analysis

[0074] The specific surface area and pore structure of the material were analyzed by using a full-automatic specific surface and porosity analyzer (BET), nitrogen gas was used as the adsorbing gas, the surface area and pore structure of the material were measured, and the specific surface area, average pore diameter and pore volume of the lithium ion sieve material were calculated according to the test results, and the results are shown in Table 1.

[0075] Table 1

[0076]

[0077]

[0078] The precursor in Table 1 refers to a manganese-based lithium ion sieve precursor. As can be seen from Table 1, the specific surface area and pore volume of the ion sieve precursor prepared in the embodiments of the present application are significantly greater than those of the comparative examples, and the average pore diameter is significantly smaller than that of the comparative examples.

[0079] 2. Adsorption capacity determination

[0080] 0.25 g of lithium ion sieve was added into 0.5 L of a lithium-containing solution (the Li concentration was 50 mg / L), mechanical stirring was carried out at room temperature at 500 r / min, samples were taken at different adsorption times, the Li + concentration in the liquid phase was determined by an inductively coupled plasma emission spectrometer, and the adsorption capacity q can be calculated by the following formula:

[0081] q = V (C0-C) / m

[0082] C0is the initial Li + concentration, mg / L; C is the Li + concentration measured at the time, mg / L, V is the volume of the lithium-containing solution, L, and m is the amount of lithium ion sieve, g.

[0083] When the Li + concentration no longer changes or changes are not obvious over time, the adsorption capacity reaches saturation. The adsorption capacity results of the lithium ion sieves prepared in various examples and comparative examples are shown in Table 2.

[0084] Table 2

[0085]

[0086] As can be seen from Table 2, the adsorption capacity of the lithium ion sieves prepared in the embodiments of the present application for lithium ions is all above 35.7 mg / g, which is much higher than that of Comparative Example 1, and the time to reach the saturated adsorption capacity is not much different. It can be seen that the adsorption efficiency of the lithium ion sieves in the embodiments of the present application is better than that of Comparative Example 1.

[0087] 3. Cycle performance

[0088] (1) 0.25 g lithium ion sieve was added into 0.5 L lithium-containing solution (Li concentration was 50 mg / L), and mechanical stirring was carried out at room temperature and 500 r / min for 4 h, and the adsorption amount was determined by sampling;

[0089] (2) After standing, solid-liquid separation was carried out to obtain the lithium ion sieve after adsorption;

[0090] (3) The lithium ion sieve was washed with 1.5 mol / L hydrochloric acid for 2 h to obtain the lithium ion sieve;

[0091] (4) The above steps (1) to (3) were cycled for about 20 times, the adsorption amount of lithium ion sieve for lithium was calculated each time, and the recycling performance of lithium ion sieve was analyzed.

[0092] Table 3

[0093]

[0094] It was calculated that the adsorption amount of the lithium ion sieve prepared in Examples 1 to 5 was reduced by less than 10% within 5 cycles; when the cycle number was increased to 20 times, the adsorption amount was reduced by about 25%;

[0095] The adsorption amount of the lithium ion sieve prepared in Comparative Example 1 was reduced by less than 10% within a small number of cycles (5 times), which was not much different from that of Example 2, but as the cycle number increased (more than 10 times), the adsorption amount was reduced very obviously, and the reduction ratio was basically more than 30%; after 15 cycles, the adsorption amount decreased very rapidly, and the adsorption effect was greatly reduced.

[0096] 4. Mn dissolution loss determination experiment

[0097] The lithium ion sieve before adsorption and lithium extraction was digested and the ion concentration of Mn was determined, and then the Mn dissolution loss rate was calculated, and the specific operation was as follows;

[0098] (1) Determination of ion concentration of Mn in ion sieve: 0.050 g of ion sieve was dissolved in 20 mL of HCl solution (6 mol / L) containing a few drops of 30% H2O2, and Mn was dissolved by stirring, and the digestion solution was formed by constant volume, and the ion concentration of Mn was determined by inductively coupled plasma emission spectrometer;

[0099] (2) 0.050 g of lithium ion sieve was added into 0.1 L lithium-containing solution (Li concentration was 50 mg / L), and mechanical stirring was carried out at room temperature and 500 r / min for 3 h, and the lithium ion sieve adsorbed Li in the solution during the stirring process, and after the adsorption was completed, the ion concentration of Mn in the residual solution was determined; +

[0100] The dissolution loss D of Mn was calculated by the following formula: Mn ​​

[0101] D Mn (%) = V 吸 *C 吸 / (V 消 *C 消 )

[0102] C 吸 is the concentration of Mn ions in the adsorption raffinate, mg / L, V 吸 is the volume of the adsorption raffinate, L; C 消 is the concentration of Mn ions in the digestion solution, mg / L, V 消 is the volume of the digestion solution, L; the calculation results are shown in Table 4 below.

[0103] Table 4

[0104]

[0105] As can be seen from Table 4, the manganese-based ion sieve prepared in the embodiment of the application has a smaller Mn dissolution loss rate, which is lower than 3.1%, lower than that of Comparative Example 1.

[0106] 5. Selective adsorption experiment

[0107] In 0.5 L of lithium-containing solution, interfering metal ions such as Na + , Ca 2+ , Mg 2+ , K + , etc. are added, the initial concentrations of the interfering ions and Li + are all 50 mg / L, 0.25 g of lithium ion sieve is added for selective adsorption experiment, the mechanical stirring speed is 500 r / min, the stirring time is 3 h, adsorption is carried out at room temperature, then the concentrations of the ions are determined, the adsorption amounts of the ions are calculated, and the results are shown in Table 5 below.

[0108] Table 5

[0109]

[0110] As can be seen from Table 5, the interfering degrees of Na + , Ca 2+ , Mg 2+ , K + , etc. on the adsorption of Li + by the lithium ion sieve of the embodiment of the application are low, and the interfering degree on Comparative Example 1 is higher than that on Example 2; the lithium ion sieve prepared in the embodiment of the application has excellent selective performance for Li + .

[0111] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the patent scope of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing a porous manganese-based lithium ion-sieve, characterized by, The preparation method comprises the following steps: pyrolyzing a manganese salt solution into a manganese-oxygen mixture by a spray pyrolysis method; the spray pyrolysis method has a temperature of 650-950 DEG C, a pyrolysis time of 5-10 h, and a gas flow rate of 2-8 L / min; sintering the manganese-oxygen mixture at a low temperature in an air atmosphere to form a nano-porous precursor Mn2O3; The nanoporous precursor Mn2O3 is mixed with lithium salt according to a set ratio, and after solid-phase calcination, a porous lithium-rich manganese oxide Li4Mn5O 12 is obtained, which is a porous manganese-based lithium ion sieve precursor. The porous lithium-rich manganese oxide Li4Mn5O 12 De-lithiated in acid, dried to obtain lithium ion sieve H4Mn5O 12 ; In the spray pyrolysis method, oxygen is used as a carrier gas; the lithium salt is used in an amount exceeding a theoretical amount, and the nano-porous precursor Mn2O3 and the lithium salt have a molar ratio of Mn:Li = 5:4-4.1; The acid is selected from formic acid, nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid or sulfurous acid, and has a concentration of 0.1-1 mol / L; the acid is used to elute lithium for 0.5-3 h; The low-temperature sintering temperature is 200-500 DEG C, and the time is 2-5 h; The solid-phase calcination temperature is 300-700 DEG C, and the calcination time is 10-24 h.

2. The method for preparing a porous manganese-based lithium ion sieve according to claim 1, characterized in that: The solid-phase calcination atmosphere is oxygen or air.

3. The method for preparing a porous manganese-based lithium ion sieve according to claim 1, characterized in that: The manganese salt solution is at least one of a manganese chloride solution, a manganese sulfate solution, a manganese acetate solution and a manganese nitrate solution.

4. The method according to claim 1 or 3, wherein the porous manganese-based lithium ion-sieve is prepared by the following steps: (1) preparing a precursor of the porous manganese-based lithium ion-sieve; (2) calcining the precursor to obtain the porous manganese-based lithium ion-sieve. The lithium salt is at least one of lithium chloride, lithium hydroxide, lithium nitrate and lithium carbonate.

5. A porous manganese-based lithium ion-sieve, characterized by, The porous manganese-based lithium ion sieve is prepared by the preparation method of any one of claims 1-4.

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