Preparation method of magnesium and calcium doped positive electrode material precursor coated by copper oxide
Through the preparation method of nickel-manganese precursor material coated with copper oxide and magnesium and calcium doped, the problems of irregular morphology and low bulk density of nickel-manganese-based precursor materials are solved, and the electrochemical performance and stability of sodium ion batteries are improved, and it is suitable for industrial production.
Patent Information
- Application Number
- CN202510579323.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-07
- Publication Date
- 2025-08-15
AI Technical Summary
The existing nickel-manganese-based precursor materials have problems of irregular morphology and low bulk density during the preparation process, and the capacity of sodium ion batteries is low, so it is necessary to improve the electrochemical performance of the cathode material.
The preparation method of nickel-manganese precursor material doped with magnesium and calcium coated under copper oxide coating was adopted. Through co-precipitation reaction and ball mill mixing, a uniform and dense precursor material was prepared, and the surface was coated with copper oxide layer, combining the doping of magnesium and calcium to control the crystal growth process.
It improves the electrochemical performance and stability of the cathode material, reduces production costs, and is suitable for industrial production.
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Figure CN120483287A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of battery materials, and in particular to a method for preparing a copper oxide-coated magnesium- and calcium-doped cathode material precursor. Background Art
[0002] Since their introduction in the 1990s, lithium-ion batteries (LIBs) have been widely used in various fields, including electric vehicles and consumer electronics, due to their high specific capacitance, excellent rate capability, and cycling stability. However, with the rapid growth in demand for LIBs, the shortage of lithium resources has become increasingly prominent, necessitating the development of alternative LIBs. Sodium-ion batteries (SIBs) have attracted widespread attention due to their similar operating principles and abundant sodium resources. However, SIBs suffer from relatively low capacity.
[0003] Therefore, the research and improvement of positive electrode materials is the key to improving the energy density and stability of sodium-ion batteries. The electrochemical properties of positive electrode materials can be improved by controlling the synthesis of precursors. In the field of nickel-manganese-based precursor materials, in the existing industrial preparation process, the most common method is the co-precipitation method using hydroxide as a precipitant. However, when the manganese content of the precursor is increased, the hydroxide precursor with a high manganese content often has problems of irregular morphology and low bulk density during the generation process. Therefore, the use of sodium carbonate as a precipitant can solve this problem to a certain extent. In addition, the type of doping elements, the content of doping elements, the coating structure, etc. of the precursor also have an important influence on the physical and chemical indicators and electrochemical properties of the positive electrode material. The synergistic doping of magnesium and calcium elements greatly improves the electrochemical performance of the positive electrode material. Summary of the Invention
[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing a cathode material precursor doped with magnesium and calcium under copper oxide coating.
[0005] To achieve the above objectives, the present invention adopts the following technical solutions.
[0006] The present invention provides a method for preparing a nickel-manganese precursor material doped with magnesium and calcium under copper oxide coating, wherein the chemical formula of the precursor material is Ni x Mn y Mg z Ca p (OH)2(CuO) q , where x, y, z, p, q are molar numbers, 0.22≤x<0.45, 0.4 <y≤0.5,0<z≤0.22,0.1<p≤0.15,0<q≤0.05,x+y+z+p=1。
[0007] The specific preparation method comprises the following steps:
[0008] (1) preparing nickel and manganese metal salt solution; preparing magnesium and calcium metal salt solution; preparing alkaline solution; preparing complexing agent solution;
[0009] (2) placing a nickel-manganese metal salt solution in a reactor and mixing it uniformly, then feeding an alkali solution and a complexing agent solution into the reactor using a metering pump, adjusting the pH value, and performing a first-stage coprecipitation reaction to obtain a mixed slurry; adding a magnesium-calcium metal salt solution to the mixed slurry, continuously stirring, and performing a second-stage coprecipitation reaction to obtain a solid-liquid mixture;
[0010] (3) Filtering the solid-liquid mixture described in step (2), washing, drying, sieving, and demagnetizing the obtained solid phase to obtain magnesium and calcium-doped nickel-cobalt-manganese precursor material A.
[0011] (4) The nickel-cobalt-manganese precursor material A obtained in step (3) is mixed with nano-copper oxide, and ethanol is added to perform ball milling. The solid phase after ball milling is dried, sieved, and demagnetized to obtain a nickel-manganese precursor material doped with magnesium and calcium coated with copper oxide.
[0012] Furthermore, the metal salts of nickel and manganese in the above preparation method are sulfates.
[0013] Furthermore, the metal salts of magnesium and calcium in the above preparation method are chlorates.
[0014] Furthermore, in the above preparation method, the alkaline solution is a Na2CO3 solution, and the complexing agent solution is an NH3·H2O solution.
[0015] Furthermore, the copper oxide in the above preparation method is nano-scale copper oxide.
[0016] Furthermore, in the above preparation method, the concentration of the Na2CO3 solution is about 1.5-3 mol / L, and the concentration of the NH3·H2O solution is 5-6 mol / L.
[0017] In the specific preparation process, the corresponding nickel-manganese metal salt solution is prepared according to the molar ratio of nickel and manganese in the precursor material, and the total concentration of metal ions in the nickel-manganese metal salt solution is 70-120g / L; the feeding rate of the alkali solution is adjusted according to the pH value of the mixed slurry.
[0018] Furthermore, in the above preparation method, the coprecipitation reaction includes a first stage and a second stage; the stirring speed of the first stage is 350-550 rpm, the pH value of the reaction system is 11.5-12.5, the ammonia concentration in the reaction system is 9-12 g / L, and the reaction time is 0.5-5 h; the stirring speed of the second stage is 350-550 rpm, the pH value of the reaction system is 7.5-9.4, the ammonia concentration in the reaction system is 2-6 g / L, and the reaction time is 12-50 h.
[0019] The first stage of the coprecipitation reaction is the initial nucleation stage, and the second stage is the doping element coprecipitation stage. The crystal particles generated in the first stage serve as a growth substrate, inducing the growth of the coprecipitated crystals in the second stage, making the precursor particles uniform. The higher pH and ammonia concentration and shorter reaction time in the first stage promote rapid nucleation. The slightly lower pH and ammonia concentration in the second stage, as well as the introduction of the doping element, ensure stable nucleation growth and uniform morphology.
[0020] During crystal growth, the surface energy of crystal particles is high, making them prone to agglomeration. This results in uneven growth of the precursor material, internal cracks, and a loose external surface, significantly negatively impacting the physical and chemical parameters and electrochemical performance of the cathode material. The simultaneous introduction of magnesium and calcium dopants in the second stage reduces the surface energy of the crystals, inducing uniform crystal growth and resulting in dense, internal crack-free material growth, enhancing the electrochemical performance of the cathode material.
[0021] On the basis of the first stage of wet co-precipitation, metal salt solutions of magnesium and calcium are directly added in the second stage to achieve the doping of magnesium and calcium in the precursor. The process is simple and easy to operate.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] (1) The precursor Ni provided by the present invention x Mn y Mg z Ca p (OH)2(CuO) q , doped with magnesium and calcium elements, the surface grain growth is more uniform and dense, without cracks, and the particle size is 2 to 5 μm.
[0024] (2) The precursor Ni provided by the present invention x Mn y Mg z Ca p (OH)2(CuO) q , coated with copper oxide nanoparticles, improving the stability and conductivity of the material.
[0025] (3) The preparation method of the present invention is simple, has low production cost, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 The precursor Ni prepared in Example 1 of the present invention 0.45 Mn 0.45 Mg 0.05 Ca 0.05 (OH)2(CuO) 0.02 SEM image of .
[0027] Figure 2 The precursor Ni prepared in Example 2 of the present invention 0.4 Mn 0.45 Mg 0.075 Ca 0.075 (OH)2(CuO) 0.02 SEM image of .
[0028] Figure 3 The precursor Ni prepared in Example 3 of the present invention 0.35 Mn 0.45 Mg 0.01 Ca 0.01 (OH)2(CuO) 0.02 SEM image of .
[0029] Figure 4 This is a cycle performance diagram of the positive electrode material sintered by Example 1 of the present invention and Comparative Example 1.
[0030] Figure 5 The precursor Ni prepared in Comparative Example 1 of the present invention is 0.5 Mn 0.5 SEM image of (OH)2.
[0031] Figure 6 The precursor Ni prepared in Comparative Example 2 of the present invention is 0.45 Mn 0.45 Mg 0.05 Ca 0.05 SEM image of (OH)2.
[0032] Figure 7 This is the electrochemical performance result of the positive electrode material obtained from the precursor prepared by the present invention. Figure 8 These are the electrochemical performance results of the positive electrode material sintered from the magnesium and calcium doped precursors prepared in Example 2 of the present invention. Figure 9 These are the electrochemical performance results of the positive electrode material sintered from the magnesium and calcium doped precursors prepared in Example 3 of the present invention. DETAILED DESCRIPTION
[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the following description is only a portion of the embodiments of the present invention, not all of them, and these embodiments should not be used to limit the scope of protection claimed in the present application. Based on the embodiments of the present invention, all other changes or modifications obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the claims of this application.
[0034] Example 1
[0035] The chemical formula of this embodiment is Ni 0.45 Mn 0.45 Mg 0.05 Ca 0.05 (OH)2(CuO) 0.02 The cathode material precursor comprises the following steps:
[0036] (1) 2 L of 4.5 mol / L NiSO4·6H2O and 2 L of 4.5 mol / L MnSO4·H2O (Ni:Mn=1:1) were placed in a reactor and mixed evenly. Then, 5 L of 2 mol / L Na2CO3 solution and 5 L of 7 mol / L NH3·H2O solution were fed into the reactor using a metering pump and stirred evenly to obtain a mixed slurry for the first stage coprecipitation reaction. The stirring speed was 400 rpm, the pH value of the reaction solution was 12, the ammonia value was 14 g / L, and the reaction was carried out for 2.5 h.
[0037] (2) 1 L of 0.5 mol / L MgCl2 solution and 1 L of 0.5 mol / L CaCl2 solution were introduced into the reactor and stirred continuously to carry out the second stage coprecipitation reaction. The stirring speed was 500 rpm, the pH value of the reaction system was 9.0, the ammonia value was 10 g / L, and the reaction was carried out for 36 hours to obtain a solid-liquid mixture;
[0038] (3) filtering the solid-liquid mixture obtained in step (2), washing, drying, and passing the obtained solid phase through a 400-mesh sieve to obtain a magnesium- and calcium-doped nickel-cobalt-manganese precursor material A;
[0039] (4) The nickel-cobalt-manganese precursor material A obtained in step (3) and nano-copper oxide are mixed in a molar ratio of 1:0.02, ethanol is added for ball milling, and the ball milling is performed at 200r for 30 minutes. The solid phase after ball milling is dried, sieved, and demagnetized to obtain a nickel-manganese precursor material doped with magnesium and calcium coated with copper oxide.
[0040] Figure 1 The precursor Ni prepared in this example 0.45 Mn 0.45 Mg 0.05 Ca 0.05(OH)2(CuO) 0.02 From the SEM image, it can be seen that the precursor material has uniform morphology, particle size is 0.5-2μm, and the surface grains grow evenly and densely.
[0041] Comparative Example 1
[0042] The chemical formula of this comparative example is Ni 0.5 Mn 0.5 The precursor of (OH)2 comprises the following steps:
[0043] 2L of 5moL NiSO4·6H2O and 2L of 5moL MnSO4·7H2O (Ni:Mn=1:1) were placed in a reactor and mixed evenly. Then, 5L of 2mol / L Na2CO3 solution and 3L of 7mol / LNH3·H2O solution were fed into the reactor using a metering pump and stirred evenly to obtain a mixed solution, which was subjected to a coprecipitation reaction. The stirring speed was 500rpm, the pH value of the reaction solution was 12, the ammonia value was 10g / L, and the reaction was carried out for 36h to obtain a solid-liquid mixture. The mixture was filtered, washed, dried, sieved, and demagnetized to obtain Ni, a precursor of a modified ternary positive electrode material for lithium-ion batteries. 0.5 Mn 0.5 (OH)2.
[0044] Figure 5 The precursor Ni prepared in Comparative Example 1 0.5 Mn 0.5 From the SEM image of (OH)2, it can be seen that the precursor material has a uniform morphology, a particle size of 1 to 5 μm, and loose surface grain growth.
[0045] The electrochemical properties of the precursors prepared in Example 1 and Comparative Example 1 were further analyzed. The precursors prepared in Example 1 and Comparative Example 1 were sintered into positive electrode materials. The sintering conditions were: heating to 850°C at 5°C per minute, keeping the temperature for 15 hours, cooling to 200°C and keeping the temperature for 4 hours. The positive electrode materials were assembled into sodium ion button batteries to test the electrochemical properties. Figure 4 As shown in Figure 2, the magnesium and calcium doped precursors prepared in Example 1 have better electrochemical performance after being sintered into positive electrode materials. Specifically, the battery of Example 1 has a first cycle capacity of 152.8 mAh g at room temperature, 2.7-4.3 V, and 0.1 C test conditions. -1 The specific capacity of 1C first cycle is 130.4mAh g -1 The specific capacity is 110.5 mAh g after 100 cycles. -1 The specific capacity and capacity retention rate are 84.7%. Figure 4The battery of Comparative Example 1 has a first cycle capacity of 153mAh g at room temperature, 2.7-4.3V voltage range, and 0.1C test conditions. -1 The specific capacity of 1C first cycle is 132.2mAh g -1 The specific capacity is 97.2 mAh g after 100 cycles. -1 The specific capacity and capacity retention rate are 73.5%.
[0046] Comparative Example 2
[0047] The chemical formula of this comparative example is Ni 0.45 Mn 0.45 Mg 0.05 Ca 0.05 The positive electrode material precursor of (OH)2 comprises the following steps:
[0048] (1) 2 L of 4.5 mol / L NiSO4·6H2O and 2 L of 4.5 mol / L MnSO4·H2O (Ni:Mn=1:1) were placed in a reactor and mixed evenly. Then, 5 L of 2 mol / L Na2CO3 solution and 5 L of 7 mol / L NH3·H2O solution were fed into the reactor using a metering pump and stirred evenly to obtain a mixed slurry for the first stage coprecipitation reaction. The stirring speed was 400 rpm, the pH value of the reaction solution was 12, the ammonia value was 14 g / L, and the reaction was carried out for 2.5 h.
[0049] (2) 1 L of 0.5 mol / L MgCl2 solution and 1 L of 0.5 mol / L CaCl2 solution were introduced into the reactor and stirred continuously to carry out the second stage coprecipitation reaction. The stirring speed was 500 rpm, the pH value of the reaction system was 9.0, the ammonia value was 10 g / L, and the reaction was carried out for 36 hours to obtain a solid-liquid mixture;
[0050] (3) filtering the solid-liquid mixture obtained in step (2), washing, drying, and passing the obtained solid phase through a 400-mesh sieve to obtain a magnesium- and calcium-doped nickel-cobalt-manganese precursor material A;
[0051] Figure 6 The precursor Ni prepared in this comparative example 0.45 Mn 0.45 Mg 0.05 Ca 0.05 From the SEM image of (OH)2, it can be seen that the precursor material has uniform morphology, a particle size of 0.5 to 2 μm, and the surface grains grow evenly and densely.
[0052] The electrochemical properties of the precursors prepared in Example 1 and Comparative Example 2 were further analyzed. The precursors prepared in Example 1 and Comparative Example 2 were sintered into positive electrode materials. The sintering conditions were: heating to 850°C at 5°C per minute, keeping the temperature for 15 hours, cooling to 200°C and keeping the temperature for 4 hours. The positive electrode materials were assembled into sodium ion button batteries to test the electrochemical properties. Figure 7 As shown in Figure 2, the magnesium and calcium doped precursors prepared in Example 1 have better electrochemical performance after being sintered into positive electrode materials. Specifically, the battery of Example 1 has a first cycle capacity of 152.8 mAh g at room temperature, 2.7-4.3 V, and 0.1 C test conditions. -1 The specific capacity of 1C first cycle is 130.4mAh g -1 The specific capacity is 110.5 mAh g after 100 cycles. -1 The specific capacity and capacity retention rate are 84.7%. Figure 7 The battery of Comparative Example 2 has a first cycle capacity of 154.4 mAh g at room temperature, 2.7-4.3 V voltage range, and 0.1C test conditions. -1 The specific capacity of 1C first cycle is 158.8mAh g -1 The specific capacity is 125 mAh g after 100 cycles. -1 The specific capacity of the material in Example 1 is not as good as that in Comparative Example 2 in the first cycle, but the capacity retention rate is relatively high. Therefore, the loss of the first cycle capacity can be offset in the subsequent cycles and the high capacity of the battery can be maintained.
[0053] Example 2
[0054] The chemical formula of this embodiment is Ni 0.4 Mn 0.45 Mg 0.075 Ca 0.075 (OH)2(CuO) 0.02 The precursor comprises the following steps:
[0055] (1) 2 L of 4 mol / L NiSO4·6H2O and 2 L of 4.5 mol / L MnSO4·H2O (Ni:Mn=4:4.5) were placed in a reactor and mixed evenly. Then, 5 L of 2 mol / L NaOH solution and 5 L of 6.5 mol / L NH3·H2O solution were fed into the reactor using a metering pump and stirred evenly to obtain a mixed slurry. The first stage of the coprecipitation reaction was carried out: the stirring speed was 500 rpm, the pH value of the reaction slurry was 12.2, the ammonia value was 16 g / L, and the reaction was carried out for 4.0 h.
[0056] (2) 1 L of 0.75 mol / L MgCl2 solution and 1 L of 0.75 mol / L CaCl2 solution were introduced into the reactor; the second stage coprecipitation reaction was carried out with continuous stirring at a stirring speed of 500 rpm, a pH value of the reaction system of 9.0, an ammonia value of 10 g / L, and the reaction was carried out for 36 h to obtain a solid-liquid mixture;
[0057] (3) Filter the solid-liquid mixture obtained in step (2), wash, dry, and pass through a 400-mesh sieve to obtain magnesium- and calcium-doped nickel-cobalt-manganese precursor material A.
[0058] (4) The nickel-cobalt-manganese precursor material A obtained in step (3) and nano-copper oxide are mixed in a molar ratio of 1:0.02, ethanol is added for ball milling, and the ball milling is performed at 200r for 30 minutes. The solid phase after ball milling is dried, sieved, and demagnetized to obtain a nickel-manganese precursor material doped with magnesium and calcium coated with copper oxide.
[0059] Reference Figure 2 The precursor Ni prepared in this example 0.4 Mn 0.45 Mg 0.075 Ca 0.075 (OH)2(CuO) 0.02 The morphology is uniform, the particle size is 1 to 4 μm, and the surface grains grow uniformly and densely. Figure 1 ,Discover Figure 1 The particles are more uniform, which is speculated to be due to the addition of Mg and Ca elements, which have some effect on the growth of the crystals.
[0060] The electrochemical properties of the precursor prepared in Example 2 were further analyzed. The precursor prepared in Example 2 was sintered into a positive electrode material. The sintering conditions were: heating to 850°C at 5°C per minute, keeping the temperature for 15 hours, cooling to 200°C and keeping the temperature for 4 hours. The positive electrode material was obtained and assembled into a sodium ion button battery to test the electrochemical performance. Figure 9 As shown in the figure, the cathode material prepared in Example 2 by sintering the magnesium and calcium doped precursors has a first cycle capacity of 131.1 mAh g at room temperature, 2.7-4.3 V, and 0.1 C test conditions. -1 The specific capacity of 1C first cycle is 138.8mAh g -1 The specific capacity is 113.3 mAh g after 100 cycles. -1 The specific capacity and capacity retention rate are 81.6%.
[0061] Example 3
[0062] The chemical formula of this embodiment is Ni 0.35 Mn 0.45 Mg 0.01 Ca0.01 (OH)2(CuO) 0.02 The precursor comprises the following steps:
[0063] (1) 2 L of 3.5 mol NiSO4·6H2O and 2 L of 4.5 mol MnSO4·H2O (Ni:Mn=3.5:4.5) were placed in a reactor and mixed evenly. Then, 5 L of 2 mol / L NaOH solution and 5 L of 7 mol / L NH3·H2O solution were fed into the reactor using a metering pump and stirred evenly to obtain a mixed slurry. The first stage of the coprecipitation reaction was carried out: the stirring speed was 400 rpm, the pH value of the reaction slurry was 12, the ammonia value was 15 g / L, and the reaction was carried out for 3.0 h.
[0064] (2) 1 mol / L MgCl2 solution and 1 mol / L CaCl2 solution were introduced into the reactor; the second stage coprecipitation reaction was carried out with continuous stirring at a stirring speed of 500 rpm, a pH value of the reaction system of 9.0, an ammonia value of 10 g / L, and the reaction was carried out for 36 hours to obtain a solid-liquid mixture;
[0065] (3) Filter the solid-liquid mixture obtained in step (2), wash, dry, and pass through a 400-mesh sieve to obtain magnesium- and calcium-doped nickel-cobalt-manganese precursor material A.
[0066] (4) The nickel-cobalt-manganese precursor material A obtained in step (3) and nano-copper oxide are mixed in a molar ratio of 1:0.02, ethanol is added for ball milling, and the ball milling is performed at 200r for 30 minutes. The solid phase after ball milling is dried, sieved, and demagnetized to obtain a nickel-manganese precursor material doped with magnesium and calcium coated with copper oxide.
[0067] Reference Figure 3 The precursor Ni prepared in this example 0.35 Mn 0.45 Mg 0.01 Ca 0.01 (OH)2(CuO) 0.02 The morphology is uniform, the surface grains grow uniformly and densely, and the particle size is 1 to 5 μm. Figure 1 ,Discover Figure 1 The particles are more uniform. Figure 3 Many small particles appeared in the sample, which was presumably due to the relatively small doping amount of Mg and Ca elements, resulting in the appearance of small particle crystals. At the same time, the ratio of Ni and Mn elements changed from 1:1 to 7:9, which also had some impact on the growth of the crystal.
[0068] The electrochemical properties of the precursor prepared in Example 3 were further analyzed. The precursor prepared in Example 3 was sintered into a positive electrode material. The sintering conditions were: heating at 5°C per minute to 850°C, keeping the temperature for 15 hours, cooling to 200°C and keeping the temperature for 4 hours. The positive electrode material was obtained and assembled into a sodium ion button battery to test the electrochemical performance. Figure 9 As shown in the figure, the cathode material prepared in Example 3 by sintering the magnesium and calcium doped precursors has a first cycle capacity of 132.2 mAh g at room temperature, 2.7-4.3 V, and 0.1 C test conditions. -1 The specific capacity of 1C first cycle is 137.8mAh g -1 The specific capacity is 113.1 mAh g after 100 cycles. -1 The specific capacity and capacity retention rate are 79.1%.
[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A nickel-manganese precursor material coated with magnesium and calcium on the surface of copper oxide, characterized by: Copper oxide particles are coated on the surface, and the chemical formula of the nickel manganese precursor material is Ni x Mn y Mg z Ca p (OH)2(CuO) q , where x, y, z, p, q are molar numbers, 0.22≤x<0.45, 0.4 <y≤0.5,0<z≤0.22,0.1<p≤0.15,0<q≤0.05,x+y+z+p=1。 2. A method for preparing a nickel-manganese precursor material doped with magnesium and calcium under copper oxide surface coating, characterized in that: The following steps are included: (1) preparing a nickel-manganese metal salt solution; preparing an alkaline solution; preparing a complexing agent solution; preparing magnesium and calcium metal salt solutions; (2) placing a nickel-cobalt-manganese metal salt solution in a reactor and mixing it uniformly, then feeding an alkali solution and a complexing agent solution into the reactor using a metering pump to perform a first-stage coprecipitation reaction to obtain a mixed slurry; adding a doped magnesium-calcium metal salt solution to the mixed slurry, continuously stirring, and performing a second-stage coprecipitation reaction to obtain a solid-liquid mixture; (3) filtering the solid-liquid mixture described in step (2), and washing, drying, and sieving the obtained solid phase to obtain a magnesium- and calcium-doped nickel-manganese precursor material A; (4) Mixing nickel-manganese precursor material A and nano-copper oxide, adding ethanol to perform ball milling, and drying, sieving, and demagnetizing the solid phase after ball milling to obtain a nickel-manganese precursor material doped with magnesium and calcium coated with copper oxide.
3. The preparation method according to claim 2, wherein: The metal salts of nickel and manganese are sulfates, the metal salts of magnesium and calcium are chlorates, the alkaline solution is Na2CO3 solution, and the complexing agent solution is NH3·H2O solution.
4. The preparation method according to claim 3, wherein: The concentration of the Na2CO3 solution is 1.5-3 mol / L, and the concentration of the complexing agent solution is 4-7 mol / L.
5. The preparation method according to claim 2, wherein: In the first stage coprecipitation reaction, the stirring speed is 350-550 rpm, the pH value of the reaction system is 11.5-12.5, the concentration of ammonia in the reaction system is 9-12 g / L, and the reaction time is 0.5-5 h.
6. The preparation method according to claim 2, wherein: In the second stage coprecipitation reaction, the stirring speed is 350-550 rpm, the pH value of the reaction system is 7.5-9.4, the concentration of ammonia in the reaction system is 2-6 g / L, and the reaction time is 12-50 h.