A method for preparing a doped manganese phosphate precursor and a doped manganese phosphate lithium positive electrode material

Abstract

The present invention provides a method for preparing a doped manganese phosphate precursor and a doped manganese phosphate lithium positive electrode material. The precursor preparation method may include: dissolving a manganous salt and a doped metal M salt and mixing them with concentrated phosphoric acid to form a mixed solution; heating the mixed solution and adding a high-valent Mn 3+n Manganese salt, after the reaction is completed, a precursor slurry is obtained, wherein the mixed solution is heated at a temperature of 150°C to 250°C; the precursor slurry is washed, filtered, and dried to obtain a doped manganese phosphate precursor. The positive electrode material preparation method comprises: mixing the doped manganese phosphate precursor with a lithium source and a carbon source, calcining in an inert atmosphere to obtain a carbon-coated LiMn x M 1‑x PO4 / C positive electrode material. The method of the invention has simple preparation process, easy operation, high efficiency, environmental friendliness and low cost, and the prepared doped manganese phosphate precursor has high phase purity, and the particle size can be controlled from nanometer to micrometer level, and has good dispersibility and high crystallinity.

Description

Technical Field

[0001] The present invention relates to the field of positive electrode materials for lithium ion batteries, and more specifically, to a method for preparing a doped manganese phosphate precursor and a doped manganese phosphate lithium positive electrode material. Background Art

[0002] Among the many lithium-ion battery cathode materials, lithium iron phosphate (LiFePO 4 ) is the preferred material system for large-scale energy storage in current commercial lithium-ion battery positive electrode materials because of its advantages such as low price, safety, stability, greenness and non-toxicity. In recent years, thanks to the promotion and application of CATL's CTP (Cell to pack) technology and BYD's blade battery technology, the energy density, safety performance, cycle life, and cost of lithium iron phosphate batteries have made further breakthroughs, prompting the installed capacity of lithium iron phosphate batteries to gradually increase. However, under the background of "dual carbon", large-scale energy storage has put forward higher requirements on battery cost, energy density, safety performance, cycle life and rate performance. LiFePO 4 The full battery operating voltage is around 3.2V, which is lower than the currently commercially available LiCoO 2 、LiNi 1-x-y Co x Al(Mn) y O 2 The working voltage of lithium-ion batteries (3.6V~3.7V) greatly limits the 4 Application range. Lithium manganese iron phosphate positive electrode material (LiMn 1-x Fe x PO 4 , where 0≤x≤0.2) 2+ / Mn 3+ Relative to Li / Li + The theoretical voltage platform is 4.1V, and the energy density is nearly 20% higher than that of lithium iron phosphate. In theory, it can replace expensive lithium cobalt oxide and ternary positive electrode materials.

[0003] At present, there is no mature process route for lithium manganese phosphate and lithium manganese iron phosphate for reference in the industry and academia. The preparation of lithium manganese phosphate and lithium manganese iron phosphate materials using manganese phosphate as a precursor is a research hotspot in the industry. The positive electrode material prepared by this process route using manganese phosphate as a precursor has the advantages of simple lithium matching, high crystallinity, uniform particle size distribution, excellent electrochemical performance, and good consistency. However, due to the Mn 3+ In aqueous solution, it will undergo disproportionation reaction and cannot exist stably, and will generate Mn 2+ With MnO 2This objective reason limits the production of manganese phosphate materials in aqueous solution, so there is currently no reliable technology for large-scale use. The existing preparation method usually uses nitrates to convert Mn into manganese phosphate in ethanol or aqueous solution. 2+ Oxidized to Mn 3+ , reacts with phosphoric acid or phosphate to form manganese phosphate (see Nanocrystalline Serrabrancaite (MnPO 4 ·H 2 O)Prepared by a Simple Precipitation Route at Low Temperature,Journal of Alloysand Compounds,2008 454 78–82 and Journal of The Electrochemical Society,MnPO 4 ·H 2 O as Electrode Material for Electrochemical Capacitors, 2018 165 (10) A2349-A2356). However, this method uses nitrate as an oxidant, which has high production costs and produces nitrogen-containing waste liquid and waste gas, causing great environmental pollution. At the same time, using ethanol as a solvent will further increase production and environmental costs. Patents with publication number CN112142028A and Self-assembly synthesis of dumbbell-like MnPO 4 ·H 2 Ohierarchical particle and its application in LiMnPO 4 / C cathode materials (Ceramics International, 2021 47 19687–19693) also proposed the use of potassium permanganate and concentrated phosphoric acid in an aqueous solution to prepare manganese phosphate materials, but the manganese source of this method is completely derived from potassium permanganate, and Mn 2+ The aqueous solution oxidation is costly and not conducive to large-scale production. Therefore, it is necessary to develop a method for preparing manganese phosphate materials by oxidation in an aqueous solution. Summary of the invention

[0004] In view of the deficiencies in the prior art, one of the purposes of the present invention is to solve one or more problems in the prior art. For example, one of the purposes of the present invention is to provide a method for preparing a doped manganese phosphate precursor and a doped manganese phosphate lithium positive electrode material.

[0005] One aspect of the present invention provides a method for preparing a doped manganese phosphate precursor, which may include the following steps: dissolving a manganous salt and a doped metal M salt and mixing them with concentrated phosphoric acid to form a mixed solution; heating the mixed solution and adding a high-valent Mn 3+n Manganese salt, after the reaction is completed, a precursor slurry is obtained, wherein the mixed solution is heated at a temperature of 150°C to 250°C, and n=1, 3, 4; the precursor slurry is washed, filtered, and dried to obtain doped manganese phosphate Mn x M 1-x PO 4 ·H 2 O precursor, wherein 0.5≤x≤1.0.

[0006] Furthermore, the concentration of the metal cation in the mixed solution may be 0.5 mol / L to 2.5 mol / L.

[0007] Furthermore, the manganous salt may be at least one of manganous sulfate, manganous acetate, manganous chloride and manganous oxalate; the doped metal M salt may be a soluble salt, and M may be at least one of Fe, Ni, Co, Mg, Ta and Nb.

[0008] Furthermore, the molar ratio of the metal cation to the phosphate in the mixed solution may be 1:(2-2.5).

[0009] Furthermore, high-priced Mn 3+n The manganese salt may be at least one of potassium permanganate, potassium manganate and manganese dioxide; the high-valent Mn 3+n The molar ratio of the manganese salt to the metal cation in the mixed solution can be 1:(1.2n-2.0n).

[0010] Furthermore, the step of obtaining the precursor slurry further includes heating the mixed solution and adding high-valent Mn 3+n Manganese salts form [Mn(PO 4 ) 2 ] 3- After the intermediate material is formed, stirring can be continued for 5 minutes to 20 hours to form a precursor slurry.

[0011] Another aspect of the present invention provides a doped manganese phosphate precursor, which can be prepared by the above-mentioned method for preparing the doped manganese phosphate precursor.

[0012] Another aspect of the present invention provides a method for preparing a doped lithium manganese phosphate positive electrode material, which may include the following steps: preparing the doped manganese phosphate Mn prepared by the above doped manganese phosphate precursor method; x M 1-x PO 4 ·H 2 O precursor is mixed with lithium source and carbon source and calcined under inert atmosphere to obtain carbon-coated LiMn xM 1-x PO 4 / C positive electrode material, wherein 0.5≤x≤1.0.

[0013] Furthermore, the lithium element contained in the lithium source and the doped manganese phosphate Mn x M 1-x PO 4 ·H 2 The ratio of the amount of metal elements in the O precursor can be n(Li):n(Mn+M)=(1-1.10):1; the amount of carbon source added can be the sum of the atomic weights of all non-lithium metals, and 5g-50g of carbon source can be added to 1mol of the total molar amount of non-lithium metals.

[0014] Furthermore, the lithium source may be Li 2 CO 3 、LiNO 3 and LiOH·H 2 O; the carbon source can be at least one of starch, polyvinyl alcohol, sucrose, citric acid and glucose; the calcination process can include keeping warm at 300°C to 500°C for 3h to 10h and then calcining at 600°C to 800°C for 5h to 20h.

[0015] Another aspect of the present invention provides a doped lithium manganese phosphate positive electrode material, which can be prepared by the above-mentioned method for preparing the doped lithium manganese phosphate positive electrode material.

[0016] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0017] (1) The method for preparing doped manganese phosphate of the present invention realizes the preparation of manganese phosphate MnPO in an aqueous solution. 4 ·H 2 O-type materials have achieved metal doping. Compared with the existing manganese phosphate material preparation process, the method of the present invention has a simple preparation process, is easy to operate, has high efficiency, is environmentally friendly, and has low cost. The prepared doped manganese phosphate precursor has high phase purity, and the particle size can be controlled from nanometer to micrometer level, with good dispersibility and high crystallinity.

[0018] (2) The positive electrode material preparation method of the present invention has the advantages of short process, low energy consumption, high atomic utilization rate, and low operation difficulty. The prepared positive electrode material has high crystallinity, uniform particle size distribution, excellent electrochemical performance, and good consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and other objects and features of the present invention will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0020] Figure 1This is the XRD spectrum of the iron-doped manganese phosphate precursor prepared in Example 1.

[0021] Figure 2 This is the SEM image of the iron-doped manganese phosphate precursor prepared in Example 1.

[0022] Figure 3 This is the charge and discharge curve of the battery assembled with the iron-doped phosphate precursor prepared in Example 1. DETAILED DESCRIPTION

[0023] Hereinafter, a method for preparing a doped manganese phosphate precursor and a doped manganese phosphate lithium positive electrode material according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0024] Specifically, the existing methods for preparing manganese phosphate materials generally only use low-valent manganese salts or high-valent manganese salts as raw materials. The use of low-valent manganese salts to prepare manganese phosphate materials requires the use of strong oxidants such as nitrates, which leads to high production costs and the generated nitrogen oxides will cause environmental pollution. The method of using high-valent manganese salts as one of the raw materials to react with phosphoric acid to prepare manganese phosphate materials has the disadvantages of high cost, and in order to avoid Mn 3+ The disproportionation reaction in water does not add additional water during the preparation process, which limits the industrial application of the method to a certain extent. At the same time, it is impossible to dope other elements during the preparation process. The method of the present invention uses a high-valent manganese salt as an oxidant to prepare a high-purity doped manganese phosphate precursor material in an acidic aqueous solution of a doped metal M salt, a manganous salt and phosphoric acid. The mixed solution is mixed with a high-valent Mn 3+n Manganese salt undergoes a redox reaction, the reaction process includes:

[0025]

[0026] The present invention is based on the strong oxidizing property of high-valent manganese salt under strong acid conditions and by exploring the 3+ Under the condition of stable existence of aqueous solution, the preparation of manganese phosphate material by oxidation of low-valent manganese salt in aqueous solution is realized, the adjustment of pH value in the reaction process is avoided, and the manganous salt and the doped metal M salt are dissolved by aqueous sulfuric acid solution or other acidic solution, and transition metal element doping is realized in the preparation process while preparing the manganese phosphate material. The method has short reaction time, low cost, simple process, environmental friendliness, green and environmental protection, and has great industrial value.

[0027] One aspect of the present invention provides a method for preparing a doped manganese phosphate precursor. In some embodiments, the preparation method may include:

[0028] Step 1, dissolving manganous salt and doping metal M salt and mixing with concentrated phosphoric acid to form a mixed solution;

[0029] Step 2: Heat the mixture and add high-priced Mn 3+n Manganese salt, after the reaction is completed, a precursor slurry is obtained, wherein the mixed solution is heated at a temperature of 150° C. to 250° C., and n=1, 3, 4;

[0030] Step 3: Wash the precursor slurry, filter it, and dry it to obtain doped manganese phosphate Mn x M 1-x PO 4 ·H 2 O precursor, wherein 0.5≤x≤1.0.

[0031] In some embodiments, manganous salt and doped metal M salt can be dissolved in sulfuric acid aqueous solution and then mixed with concentrated phosphoric acid to form a mixed solution. By using sulfuric acid aqueous solution to dissolve manganous salt and doped metal M salt, transition metal element doping is achieved during the preparation process while preparing manganese phosphate material. The sulfuric acid aqueous solution can be a sulfuric acid aqueous solution with a sulfuric acid concentration of 1 mol / L to 18 mol / L. For example, the sulfuric acid concentration in the sulfuric acid aqueous solution is 9 mol / L. The concentrated phosphoric acid can be a concentrated phosphoric acid with a mass fraction of 40 wt% to 85 wt%. For example, the mass fraction of concentrated phosphoric acid can be 60 wt% of concentrated phosphoric acid.

[0032] In some embodiments, the manganous salt can be at least one of manganous sulfate, manganous acetate, manganous chloride and manganous oxalate. Of course, the manganous salt of the present invention is not limited thereto, and any soluble salt of divalent manganese element can be used.

[0033] In some embodiments, the doping metal M salt may be a soluble salt. The doping metal M may be at least one of Fe, Ni, Co, Mg, Ta and Nb.

[0034] In some embodiments, the metal cation concentration in the mixed solution can be 0.5mol / L to 2.5mol / L. The metal cation concentration within the above range can provide a higher yield of the metal element. For example, in some embodiments, the metal cation concentration in the mixed solution can be 0.7mol / L to 2.3mol / L, 0.9mol / L to 2.0mol / L, 1.1mol / L to 1.8mol / L, 1.4mol / L to 1.6mol / L, or a combination of the above ranges.

[0035] In some embodiments, the high-valent Mn 3+n The manganese salt may be a manganese salt in which the element manganese is +4, +6 or +7, or a mixture of manganese salts in which the element manganese is +4, +6 and +7. 3+n The manganese salt may be at least one of potassium permanganate, potassium manganate and manganese dioxide. 3+nThe molar ratio of manganese salt to metal cation in the mixed solution can be 1:(1.2n-2.0n), where n=1, 3, or 4. For example, high-valent Mn 3+n The molar ratio of the manganese salt to the metal cation in the mixed solution can be 1:(1.2-2.0), or 1:(3.6-6.0), or a combination thereof. For another example, the molar ratio can be 1:1.8, 1:2.5, 1:5.4, or 1:7.2.

[0036] In some embodiments, the molar ratio of the metal cation to the phosphate in the mixed solution may be 1:(2-2.5). For example, the molar ratio of the metal cation to the phosphate in the mixed solution may be 1:2.1, 1:2.2, 1:2.3 or 1:2.4.

[0037] In some embodiments, the temperature of the mixed solution heating can be 150° C. to 250° C., within which the mixed solution can react with the high-valent manganese salt. For example, the temperature of the mixed solution heating can be 162° C. to 241° C., 175° C. to 232° C., 189° C. to 218° C., 195° C. to 207° C., or a combination of the above ranges.

[0038] In some embodiments, the step of obtaining the precursor slurry in step 2 may further include boiling and concentrating the mixed solution obtained in step 1 and heating it to 150° C. to 250° C. to mix with the high-valent Mn 3+n Manganese salt mix.

[0039] In some embodiments, the mixed solution in step 2 is mixed with high-valent Mn 3+n After the manganese salts are mixed, a redox reaction will occur, and a uniform mixture containing [Mn(PO 4 ) 2 ] 3- After the reaction is completed, the intermediate liquid is stirred for a certain period of time to obtain a gray-green precursor slurry. For example, the stirring time after the reaction is completed can be 5min to 20h. For example, the stirring time can be 20min to 18h, 50min to 15h, 3h to 12h, 5h to 10h, 7h to 9h or a combination of the above ranges. The high-priced Mn 3+n The manganese salt can be continuously added to the heated mixed solution under stirring, and the addition time can be 5s to 50h.

[0040] In some embodiments, step 3 may include washing with deionized water at 20°C to 100°C for 3 to 5 times, and the amount of deionized water added each time may be 2 to 100 times the mass of the precursor; the drying temperature may be 60°C to 150°C, and the drying time may be 5h to 50h.

[0041] Another aspect of the present invention provides a doped manganese phosphate precursor. In some embodiments, the doped manganese phosphate precursor can be prepared by the above-mentioned method for preparing the doped manganese phosphate precursor.

[0042] Another aspect of the present invention provides a method for preparing a doped lithium manganese phosphate positive electrode material. In some embodiments, the preparation method may include the following steps:

[0043] The doped manganese phosphate Mn prepared by the above-mentioned preparation method of the doped manganese phosphate precursor x M 1-x PO 4 ·H 2 O precursor is mixed with lithium source and carbon source and calcined under inert atmosphere to obtain carbon-coated LiMn x M 1-x PO 4 / C positive electrode material, wherein the value of x in the chemical formula of the precursor and the positive electrode material can be 0.5≤x≤1.0.

[0044] In some embodiments, the lithium source contains lithium and doped manganese phosphate Mn x M 1-x PO 4 ·H 2 The molar ratio of the metal elements in the O precursor may be n(Li):n(Mn+M)=(1-1.10):1. For example, the molar ratio may be n(Li):n(Mn+M)=1.02:1 or 1.05:1 or 1.08:1.

[0045] In some embodiments, the amount of carbon source added can be based on the total atomic weight of all non-lithium metals (i.e., metal cations other than lithium), and 5g to 50g of carbon source can be added to 1mol of the total molar amount of non-lithium metals. For example, 10g to 40g of carbon source can be added to 1mol of the total molar amount of non-lithium metals, and for another example, 20g to 30g of carbon source can be added.

[0046] In some embodiments, the calcination process may include calcining at 600°C to 800°C for 5 to 20 hours after keeping at 300°C to 500°C for 3 to 10 hours. For example, the calcination process may include calcining at 700°C for 12 hours after keeping at 400°C for 6 hours.

[0047] In some embodiments, the lithium source may be Li 2 CO 3 、LiNO 3 and LiOH·H 2 The carbon source may be at least one of starch, polyvinyl alcohol, sucrose, citric acid and glucose.

[0048] Another aspect of the present invention provides a doped lithium manganese phosphate positive electrode material. In some embodiments, the positive electrode material can be prepared by the above-mentioned method for preparing the doped lithium manganese phosphate positive electrode material, and the positive electrode material is carbon-coated LiMn x M 1- x PO 4 / C positive electrode material, wherein 0.5≤x≤1.0.

[0049] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific examples, but the content of the present invention is not limited to the following examples.

[0050] Example 1

[0051] Step 1, weigh 2.8g of ferrous sulfate, 11.2g of manganous sulfate and 23.2g of 85% concentrated phosphoric acid, add them into a 200ml conical flask, dissolve them in 1mol / L sulfuric acid aqueous solution, stir evenly, and obtain a mixed solution.

[0052] Step 2, heating and stirring the obtained mixed solution, adding 6 g of potassium permanganate when the temperature reaches 250° C., and maintaining the solution at 250° C. for reaction for 1 hour, and obtaining a precursor slurry after the reaction is completed.

[0053] Step 3: Filter, wash and dry the precursor slurry to obtain gray-green iron-doped manganese phosphate Mn 0.8 Fe 0.2 PO 4 ·H 2 O powder, the yield of transition metal and manganese ion is about 99%. The prepared iron-doped manganese phosphate precursor was tested by XRD, and the results are as follows Figure 1 As shown. Figure 1 It can be seen that the iron-doped manganese phosphate precursor obtained in this embodiment is mainly composed of manganese phosphate monohydrate.

[0054] The iron-doped manganese phosphate precursor prepared in this example was subjected to SEM examination, and the results were as follows: Figure 2 As shown. Figure 2 It can be seen that the manganese phosphate prepared in this embodiment has a uniform particle size distribution, and its particles are nano-micron spherical particles.

[0055] The precursor obtained in this embodiment is mixed with lithium, and the mixing ratio is 1.10:1 for the molar ratio of lithium source to precursor substance, and the amount of carbon source added is 0.5g. Because the precursor is a nano-micron particle, ball milling is used for mixing, and the ball milling procedure is: speed 400rpm, time 4h. After the ball milling is completed, the sample is placed in a tubular furnace for roasting. The product roasting process is carried out in a nitrogen atmosphere. The roasting procedure is to keep warm at 300°C for 3h and roast at 800°C for 20h. The product is subjected to electrochemical testing, and the results are as follows Figure 3As shown. Figure 3 It can be seen that the battery assembled using the iron-doped manganese phosphate precursor obtained in this example can achieve a discharge capacity of 151.8 mAh g at 0.1C. -1 .

[0056] Example 2

[0057] Step 1, weigh 2.8g of ferrous sulfate, 11.2g of manganous sulfate and 23.2g of 85% concentrated phosphoric acid, add them into a 200ml conical flask, dissolve them in 6mol / L sulfuric acid aqueous solution, stir evenly, and obtain a mixed solution.

[0058] Step 2: Heat and stir the obtained mixed solution until the temperature reaches 200° C., then add 12 g of manganese dioxide, and keep the solution at 200° C. for 10 hours to obtain a precursor slurry after the reaction is completed.

[0059] Step 3: Filter, wash and dry the precursor slurry to obtain gray-green iron-doped manganese phosphate Mn 0.8 Fe 0.2 PO 4 ·H 2 O powder, transition metal and manganese ion ratio is about 99%.

[0060] The precursor obtained in this embodiment is mixed with lithium, and the ratio of lithium source to precursor is 1.03:1, and the amount of carbon source added is 1.5g. Because the precursor is a nano-micron particle, ball milling is used for mixing, and the ball milling procedure is: speed 400rpm, time 4h. After the ball milling is completed, the sample is placed in a tubular furnace for roasting. The product roasting process is carried out in an argon atmosphere. The roasting procedure is to keep warm at 400°C for 7h and roast at 750°C for 10h. The product is subjected to electrochemical testing. The battery assembled with the iron-doped manganese phosphate precursor obtained in this embodiment has a discharge capacity of 148.6mAh g at 0.1C. -1 .

[0061] Example 3

[0062] Step 1, weigh 2.8g of ferrous sulfate, 11.2g of manganous sulfate and 23.2g of 85% concentrated phosphoric acid, add them into a 200ml conical flask, dissolve them in 98mol / L sulfuric acid aqueous solution, stir evenly, and obtain a mixed solution.

[0063] Step 2, heating and stirring the obtained mixture until the temperature reaches 150° C., adding 6 g of potassium manganate, and maintaining the solution at 150° C. for reaction for 5 min, and obtaining a precursor slurry after the reaction is completed.

[0064] Step 3: Filter, wash and dry the precursor slurry to obtain gray-green manganese phosphate Mn 0.8 Fe0.2 PO 4 ·H 2 O powder, transition metal and manganese ions are about 99%.

[0065] The precursor obtained in this embodiment is mixed with lithium, and the ratio of lithium source to precursor is 1:1, and the amount of carbon source added is 5g. Because the precursor is a nano-micron particle, ball milling is used for mixing, and the ball milling procedure is: speed 400rpm, time 4h. After the ball milling is completed, the sample is placed in a tubular furnace for roasting. The product roasting process is carried out in a nitrogen atmosphere. The roasting procedure is to keep warm at 350°C for 10h and roast at 700°C for 5h. The product is subjected to electrochemical testing. The battery assembled with the iron-doped manganese phosphate precursor obtained in this embodiment has a discharge capacity of 145.7mAh g at 0.1C. -1 .

[0066] Although the present invention has been described above by combining with exemplary embodiments, it will be apparent to those skilled in the art that various modifications and changes may be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined in the claims.

Claims

1. A method for preparing a doped manganese phosphate precursor, It is characterized in that The following steps are involved: Add manganous sulfate, ferrous sulfate and concentrated phosphoric acid into a 200 ml conical flask, dissolve in sulfuric acid aqueous solution, and stir evenly to form a mixed solution; The obtained mixed solution was heated and stirred, and potassium manganate was added when the temperature reached 150° C., and the solution was kept at 150° C. for reaction for 5 minutes. After the reaction was completed, a precursor slurry was obtained; The precursor slurry is washed, filtered, and dried to obtain doped manganese phosphate Mn x Fe 1-x PO 4 ·H 2 O precursor, wherein 0.5≤x≤1.

0.

2. A doped manganese phosphate precursor, It is characterized in that The doped manganese phosphate precursor is prepared by the preparation method of claim 1.

3. A method for preparing a doped lithium manganese phosphate positive electrode material, It is characterized in that The following steps are involved: The doped manganese phosphate Mn prepared by the method for preparing the doped manganese phosphate precursor according to claim 1 x Fe 1-x PO 4 ·H 2 O precursor is mixed with lithium source and carbon source and calcined under inert atmosphere to obtain carbon-coated LiMn x Fe 1-x PO 4 / C positive electrode material, wherein 0.5≤x≤1.

0.

4. The method for preparing the doped lithium manganese phosphate positive electrode material according to claim 3, It is characterized in that Lithium element contained in lithium source and doped manganese phosphate Mn x Fe 1-x PO 4 ·H 2 The molar ratio of the metal elements in the O precursor is n(Li):n(Mn+Fe)=(1-1.10):1; the amount of carbon source added is the sum of the atomic weights of all non-lithium metals, and 5g-50g of carbon source is added to 1mol of the total molar amount of non-lithium metals.

5. The method for preparing the doped lithium manganese phosphate positive electrode material according to claim 3 or 4, It is characterized in that Lithium source is Li 2 CO 3 、LiNO 3 and LiOH·H 2 At least one of O; The carbon source is at least one of starch, polyvinyl alcohol, sucrose, citric acid and glucose; The calcination process includes keeping the temperature at 300°C to 500°C for 3h to 10h and then calcining at 600°C to 800°C for 5h to 20h.

6. A doped lithium manganese phosphate positive electrode material, It is characterized in that The doped lithium manganese phosphate positive electrode material is prepared by the preparation method of any one of claims 3 to 5.

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