A lithium-rich manganese-based positive electrode material modified by an electrolyte and a preparation method thereof

Abstract

The application provides a lithium-rich manganese-based positive electrode material modified by an electrolyte and a preparation method thereof, and the preparation method comprises the following steps: providing a lithium-rich manganese-based positive electrode material and an electrolyte material; mixing the lithium-rich manganese-based positive electrode material with the electrolyte material, adding a fluxing agent to perform sintering, and obtaining the lithium-rich manganese-based positive electrode material modified by the electrolyte. The application can improve the problems of low ion conductivity and poor long-term cycle stability of the lithium-rich manganese-based positive electrode material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium-rich manganese-based positive electrode materials, and particularly relates to an electrolyte-modified lithium-rich manganese-based positive electrode material and a preparation method thereof. BACKGROUND

[0002] As a kind of energy storage device, lithium ion battery has the advantages of small self-discharge, long cycle life, large specific energy and environmental protection, and has been widely used in 3C product field. However, the actual energy density of commercial lithium ion battery is slowly increased due to the embedded energy storage mechanism of its own material, and gradually approaches the limit value of 300 Wh / kg. Therefore, in order to meet the consumer demand of electric vehicle market, it is the social consensus to develop secondary batteries with higher energy density.

[0003] In recent years, lithium-rich manganese-based positive electrode material is expected to be used as the next generation of high-energy-density positive electrode material due to its ultra-high discharge specific capacity, and is widely used in power battery. However, the lithium-rich manganese-based positive electrode material still has the problems of low ionic conductivity, poor rate performance and poor cycle stability due to many side reactions between electrode and electrolyte during long-term cycle.

[0004] In the related art, the methods for improving the above problems mainly include element doping or material particle surface coating oxide. However, the element doping method can only improve the ionic conductivity and rate performance of lithium-rich manganese-based electrode material, and the particle surface coating method can only improve the long-term cycle stability, and cannot improve the problems of low ionic conductivity and poor long-term cycle stability of lithium-rich manganese-based material at the same time. SUMMARY

[0005] Embodiments of the present application provide an electrolyte-modified lithium-rich manganese-based positive electrode material and a preparation method thereof, which can improve the technical problems of low ionic conductivity and poor long-term cycle stability of lithium-rich manganese-based positive electrode material.

[0006] In a first aspect, embodiments of the present application provide a preparation method of an electrolyte-modified lithium-rich manganese-based positive electrode material, which comprises the following steps:

[0007] providing a lithium-rich manganese-based positive electrode material and an electrolyte material;

[0008] mixing the lithium-rich manganese-based positive electrode material and the electrolyte material, adding a fluxing agent for sintering, to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material;

[0009] The chemical formula of the lithium-rich manganese-based positive electrode material is xLi2MnO3·(1-x)LiMO2, and M is at least two of Mn, Co and Ni elements, and 0≤x≤1.

[0010] The chemical formula of the electrolyte material is Li 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M is at least two of Mn, Co and Ni elements, M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf and Sn, M Ⅴ is at least one of Nb, Ta, V and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, 0≤e≤0.6;

[0011] The chemical formula of the electrolyte-modified lithium-rich manganese-based positive electrode material is xLi2MnO3·(1-x)LiMO2·αLi 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M is at least two of Mn, Co and Ni elements, M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf and Sn, M Ⅴ is at least one of Nb, Ta, V and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, 0≤e≤0.6, 0≤α≤0.1, 0≤x≤1.

[0012] In an embodiment, the added amount of the electrolyte material is 0-3% of the added amount of the lithium-rich manganese-based positive electrode material in terms of mole percentage.

[0013] In an embodiment, the sintering temperature is 300-700℃, and the sintering time is 2-8h.

[0014] In an embodiment, the fluxing agent is at least one of B2O3, KF, BaCl2, CaCl2, LiCl, Na2B4O7, Li2B4O7, Na2BO3, NaCl, KCl, and Li2BO2.

[0015] In an embodiment, the method for preparing the electrolyte material comprises the steps of:

[0016] mixing a silicon source, a phosphorus source, a sodium source, a zirconium source, and a first metal source, a second metal source, a third metal source, a fourth metal source, and a complexing agent to obtain a mixed solution;

[0017] evaporating the mixed solution by heating to obtain a gel, and then drying and dispersing the gel to obtain an intermediate product;

[0018] calcining the intermediate product to obtain a precursor material;

[0019] mixing the precursor material with a lithium salt and a liquid carrier in an inert gas atmosphere, and then performing an ion exchange reaction to obtain the electrolyte material;

[0020] In an embodiment, the first metal source is at least one of a copper source, a magnesium source, a zinc source, a manganese source, a calcium source, a palladium source, and a strontium source, the second metal source is at least one of an aluminum source, a scandium source, a gallium source, a yttrium source, a lanthanum source, and an indium source, the third metal source is at least one of a cerium source, a titanium source, a cadmium source, a hafnium source, and a tin source, and the fourth metal source is at least one of a niobium source, an antimony source, a vanadium source, and a tantalum source.

[0021] In an embodiment, the step of calcining the intermediate product to obtain a precursor material comprises:

[0022] calcining the intermediate product at a temperature of 800-1000℃ in an air atmosphere to obtain the precursor material.

[0023] In an embodiment, the ion exchange reaction is performed at a temperature of 150-250℃.

[0024] In an embodiment, the liquid carrier is at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate, and 1-hexyl-3-methylimidazolium hexafluorophosphate.

[0025] In an embodiment, the lithium salt is one of lithium hexafluorophosphate, lithium bis-trifluoromethylsulfonylimide, lithium bis-difluorosulfonylimide, and lithium tetrafluoroborate.

[0026] In a second aspect, the embodiments of the present application provide a lithium-rich manganese-based positive electrode material modified by an electrolyte.

[0027] The embodiments of the present application have the following beneficial effects:

[0028] In the embodiments of the present application, the lithium-rich manganese-based positive electrode material is modified by the electrolyte material to obtain the lithium-rich manganese-based positive electrode material modified by the electrolyte. On the one hand, the electrolyte coated on the surface of the lithium-rich manganese-based positive electrode material can improve the ion diffusion rate between the lithium-rich manganese-based positive electrode materials, thereby effectively improving the ion conductivity of the lithium-rich manganese-based positive electrode material and improving its rate performance. On the other hand, the electrolyte material has strong structural stability and chemical stability. During the modification of the lithium-rich manganese-based positive electrode material, the electrolyte material does not react with the lithium-rich manganese-based positive electrode material to generate additional impurity phases, thereby avoiding the influence of the impurity phases on the performance of the prepared lithium-rich manganese-based positive electrode material modified by the electrolyte. After the modification process is completed, the electrolyte material can prevent the lithium-rich manganese-based positive electrode material modified by the electrolyte from contacting the electrolyte, thereby avoiding the occurrence of side reactions. At the same time, the modification by the electrolyte can inhibit the dissolution of manganese elements in the lithium-rich manganese-based positive electrode material, which is conducive to improving the voltage attenuation of the lithium-rich manganese-based positive electrode material during the cycle process and improving the long-term cycle stability of the lithium-rich manganese-based positive electrode material modified by the electrolyte. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0030] Figure 1 is a flowchart of the preparation method of the lithium-rich manganese-based positive electrode material modified by the electrolyte provided by the embodiments of the present application;

[0031] Figure 2 is a flowchart of the preparation method of the electrolyte material provided by the embodiments of the present application;

[0032] Figure 3 is an XRD test graph of the lithium-rich manganese-based positive electrode material modified by the electrolyte prepared by the embodiments 1 to 4 of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be apparently and completely described below with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person skilled in the art without any creative work belong to the protection scope of the present application. In addition, it should be understood that the specific embodiments described herein are only used for illustration and explanation of the present application, and are not used for limiting the present application. In the present application, the orientation words such as 'upper' and 'lower' generally refer to the upper and lower in the actual use or working state of the device, and specifically refer to the drawing surface direction in the drawings; and 'inner' and 'outer' refer to the outline of the device.

[0034] As shown in Figure 1 , the embodiment of the present application provides a preparation method of electrolyte-modified lithium-rich manganese-based positive electrode material, which comprises the following steps:

[0035] S10, providing a lithium-rich manganese-based positive electrode material and an electrolyte material;

[0036] S20, mixing the lithium-rich manganese-based positive electrode material and the electrolyte material, adding a fluxing agent for sintering, to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material;

[0037] The chemical formula of the lithium-rich manganese-based positive electrode material is xLi2MnO3·(1-x)LiMO2, and M is at least two of Mn, Co and Ni elements, 0≤x≤1.

[0038] The chemical formula of the electrolyte material is Li 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M is at least two of Mn, Co and Ni elements, M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf and Sn, and M Ⅴat least one of Nb, Ta, V and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, 0≤e≤0.6, 0≤α≤0.1, 0≤x≤1.

[0039] The chemical formula of the electrolyte-modified lithium-rich manganese-based positive electrode material is xLi2MnO3·(1-x)LiMO2·αLi 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M is at least two of Mn, Co and Ni elements, M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf and Sn, M Ⅴ at least one of Nb, Ta, V and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, 0≤e≤0.6, 0≤α≤0.1, 0≤x≤1.

[0040] In the embodiment, the lithium-rich manganese-based positive electrode material is modified by the electrolyte material to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material. On the one hand, the electrolyte material is an excellent fast ion conductor, and the ion conductivity is as high as 10 -3The S / cm ratio is much higher than that of the lithium-rich manganese-based cathode material. Therefore, by coating the surface of the electrolyte-modified lithium-rich manganese-based cathode material with the electrolyte, the ion diffusion rate between the lithium-rich manganese-based cathode materials can be improved, thereby effectively improving the ionic conductivity of the lithium-rich manganese-based cathode material and improving its rate performance. On the other hand, the electrolyte material has strong structural and chemical stability. During the modification process of the lithium-rich manganese-based cathode material, the electrolyte material will not react with the lithium-rich manganese-based cathode material to generate additional impurity phases, avoiding the influence of impurities on the performance of the prepared electrolyte-modified lithium-rich manganese-based cathode material. Moreover, after the modification process is completed, the electrolyte material can prevent the electrolyte-modified lithium-rich manganese-based cathode material from contacting the electrolyte, thereby avoiding the occurrence of side reactions. At the same time, through the electrolyte modification, the dissolution of manganese in the lithium-rich manganese-based cathode material can be suppressed, which is beneficial to improving the voltage decay during the cycling process of the electrolyte-modified lithium-rich manganese-based cathode material and improving the long-term cycling stability of the electrolyte-modified lithium-rich manganese-based cathode material.

[0041] Understandably, in this embodiment, in order to uniformly coat the surface of the lithium-rich manganese-based electrode material, the electrolyte material is used to be nanoscale in size.

[0042] The amount of electrolyte material added is 0-3% of the amount of lithium-rich manganese-based cathode material added, by molar percentage.

[0043] Specifically, the sintering temperature in step S20 is 300-700℃, and the sintering time is 2-8 hours. Preferably, the flux added in step S20 is at least one selected from B2O3, KF, BaCl2, CaCl2, LiCl, Na2B4O7, Li2B4O7, Na2BO3, NaCl, KCl, and Li2BO2.

[0044] Furthermore, such as Figure 2 As shown, in this embodiment, the preparation method of the electrolyte material includes the following steps:

[0045] S11. Mix silicon source, phosphorus source, sodium source, zirconium source, first metal source, second metal source, third metal source, fourth metal source and complexing agent to obtain a mixed solution;

[0046] S12. The mixed solution is heated and evaporated to obtain a gel, and then the gel is dried and dispersed to obtain an intermediate product;

[0047] S13. The intermediate product is calcined to obtain the precursor material;

[0048] S14, mixing the precursor material with a lithium salt, a liquid carrier under an inert gas atmosphere, and then performing an ion exchange reaction to obtain the electrolyte material;

[0049] wherein the first metal source is at least one of a copper source, a magnesium source, a zinc source, a manganese source, a calcium source, a palladium source, and a strontium source, the second metal source is at least one of an aluminum source, a scandium source, a gallium source, a yttrium source, a lanthanum source, and an indium source, the third metal source is at least one of a cerium source, a titanium source, a cadmium source, a hafnium source, and a tin source, and the fourth metal source is at least one of a niobium source, an antimony source, a vanadium source, and a tantalum source.

[0050] Specifically, in the present embodiment, the precursor material is prepared by a solution-assisted solid-phase reaction method. After obtaining a mixed solution, the pH of the mixed solution is controlled to be 1-3, the mixed solution is evaporated by heating until a gel is formed, the gel is dried and then dispersed by a ball mill to obtain an intermediate product, and finally the intermediate product is calcined to obtain the precursor material.

[0051] wherein step S13, the step of calcining the intermediate product to obtain the precursor material, comprises:

[0052] The intermediate product is calcined at a temperature of 800-1000°C under an air atmosphere to obtain the precursor material.

[0053] In the present embodiment, the chemical formula of the obtained precursor material is Na 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba, and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La, and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf, and Sn, M Ⅴ is at least one of Nb, Ta, V, and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, and 0≤e≤0.6.

[0054] Further, in the embodiment, after the precursor material is obtained, the precursor material is mixed with the lithium salt and the liquid carrier to perform the ion exchange reaction in an inert gas environment to obtain a reaction product, wherein the lithium salt is one of lithium hexafluorophosphate, lithium bis-trifluoromethylsulfonylimide, lithium bis-difluorosulfonylimide and lithium tetrafluoroborate, the liquid carrier is at least one of 1-ethyl-3-methylimidazolium bis-trifluoromethylsulfonimide, 1-butyl-3-methylimidazolium bis-trifluoromethylsulfonimide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium hexafluorophosphate, and preferably, the ion exchange reaction is performed at a temperature of 150-250°C. Then, the reaction product is filtered, washed and dried to obtain the electrolyte material. Preferably, the electrolyte material has a particle size of 100-2000 nm, a specific surface area of 10-30 m 2 / g, and the conductivity of the electrolyte material prepared in the embodiment is 0.1-5 mS / cm in a related conductivity test.

[0055] It should be noted that the liquid carrier used in the embodiment can be reused through zeolite adsorption renewable process, so as to reduce the preparation cost of the electrolyte material, and further reduce the preparation cost of the lithium-rich manganese-based positive electrode material modified by the electrolyte.

[0056] Further, in the embodiment, the lithium-rich manganese-based positive electrode material is obtained by co-sintering of a precursor and a lithium source, wherein the precursor is prepared by co-precipitation reaction of a mixed solution of nickel salt, cobalt salt and manganese salt and a precipitator sodium hydroxide or sodium carbonate, and the lithium source is lithium hydroxide or lithium carbonate.

[0057] In a second aspect, the embodiment provides a lithium-rich manganese-based positive electrode material modified by an electrolyte, which is prepared by the method for preparing the lithium-rich manganese-based positive electrode material modified by an electrolyte.

[0058] The technical solutions of the present application will be further described in the specific embodiments.

[0059] Embodiment 1

[0060] Preparation of raw materials:

[0061] The lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.25 Co 0.25 Mn 0.5 O2 and the electrolyte material Li 3.4 Zr2Si 2.4 P 0.6 O 12 .

[0062] Preparation of electrolyte-modified lithium-rich manganese-based positive electrode material:

[0063] The electrolyte material was dispersed by a ball mill to obtain electrolyte material with a particle size of 100 nm. The electrolyte material was mixed with the lithium-rich manganese-based positive electrode material at a molar ratio of 0.003:1, and then sintered at 650°C for 5 h to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.25 Co 0.25 Mn 0.5 O2·0.003Li 3.4 Zr2Si 2.4 P 0.6 O 12

[0064] Example 2

[0065] Preparation of raw materials:

[0066] A lithium-rich manganese-based positive electrode material 0.3Li2MnO3·0.7LiNi 0.5 Mn 0.5 O2 and an electrolyte material Li 3.3 Zr2Si 2.3 P 0.7 O 12

[0067] Preparation of electrolyte-modified lithium-rich manganese-based positive electrode material:

[0068] The electrolyte material was dispersed by a ball mill to obtain electrolyte material with a particle size of 100 nm. The electrolyte material was mixed with the lithium-rich manganese-based positive electrode material at a molar ratio of 0.003:1, and then sintered at 650°C for 5 h to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material 0.3Li2MnO3·0.7LiNi 0.5 Mn 0.5 O2·0.003Li 3.3 Zr2Si 2.3 P 0.7 O 12

[0069] Example 3

[0070] Preparation of raw materials:

[0071] A lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiCo 0.5 Mn 0.5 O2 and an electrolyte material Li 3.3 Zr 1.9 Nb 0.1 Si 2.4 P 0.6 O​​​12 .

[0072] Preparation of electrolyte-modified lithium-rich manganese-based positive electrode material:

[0073] The electrolyte material was dispersed by a ball mill to obtain electrolyte material with a particle size of 100 nm. The electrolyte material was mixed with the lithium-rich manganese-based positive electrode material at a molar ratio of 0.003:1, and then sintered at 650°C for 5 h to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.5 Mn 0.5 O2·0.003Li 3.3 Zr 1.9 Nb 0.1 Si 2.4 P 0.6 O 12 .

[0074] Example 4

[0075] Preparation of raw materials:

[0076] A lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.5 Co 0.5 O2 was provided. 2.9 Zr 1.9 Ta 0.1 Si2PO 12 .

[0077] Preparation of electrolyte-modified lithium-rich manganese-based positive electrode material:

[0078] The electrolyte material was dispersed by a ball mill to obtain electrolyte material with a particle size of 100 nm. The electrolyte material was mixed with the lithium-rich manganese-based positive electrode material at a molar ratio of 0.003:1, and then sintered at 650°C for 5 h to obtain the electrolyte-modified lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.5 Co 0.5 O2·0.003Li 2.9 Zr 1.9 Ta 0.1 Si2PO 12 .

[0079] Comparative Example 1

[0080] A lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.25 Co 0.25 Mn 0.5 O2 was provided.

[0081] Comparative Example 2

[0082] A lithium-rich manganese-based positive electrode material 0.3Li2MnO3·0.7LiNi 0.5 Mn 0.5 O2.

[0083] Comparative Example 3

[0084] A lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiCo 0.5 Mn 0.5 O2.

[0085] Comparative Example 4

[0086] A lithium-rich manganese-based positive electrode material 0.2Li2MnO3·0.8LiNi 0.5 Co 0.5 O2.

[0087] Figure 3 XRD (X-ray diffraction) patterns of the electrolyte-modified lithium-rich manganese-based positive electrode materials prepared in Examples 1 to 4, Figure 3 The 003 characteristic peak and the 104 characteristic peak shown in the XRD pattern in the above table are two main characteristic peaks of the lithium-rich manganese-based material, and since the amount of the electrolyte material used in the modification is small, the 003 characteristic peak and the 104 characteristic peak specific to the lithium-rich manganese-based positive electrode material are still dominant in the XRD pattern after the modification, the positions of the 003 characteristic peak and the 104 characteristic peak do not shift significantly, and the peak intensity of the 003 characteristic peak and the 104 characteristic peak also does not change significantly, which indicates that the electrolyte-modified lithium-rich manganese-based positive electrode material is prepared.

[0088] Further, in this embodiment, the photoelectric properties of the electrolyte-modified lithium-rich manganese-based positive electrode materials prepared in Examples 1 to 4 and the lithium-rich manganese-based positive electrode materials prepared in Comparative Examples 1 to 4 are tested, and the results are shown in the following table:

[0089]

[0090] As can be seen from the data in the table, the conductivity, rate performance, cycle performance, and high-temperature storage capacity retention rate of the electrolyte-modified lithium-rich manganese-based positive electrode material are all significantly improved compared with the unmodified lithium-rich manganese-based positive electrode material.

[0091] The principles and implementation modes of the present application are described by using specific examples in this paper, and the above examples are only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description should not be understood as a limitation of the present application.

Claims

1. A method for preparing a lithium-rich manganese-based positive electrode material modified with an electrolyte, characterized in that, The application relates to a lithium-rich manganese-based positive electrode material and an electrolyte material. The lithium-rich manganese-based positive electrode material is mixed with the electrolyte material, a fluxing agent is added for sintering, and the lithium-rich manganese-based positive electrode material modified by the electrolyte is obtained. The preparation method of the electrolyte material comprises the following steps: The lithium-rich manganese-based positive electrode material has a chemical formula of xLi2MnO3 (1-x)LiMO2, and M is at least two of Mn, Co, and Ni elements, 0 The chemical formula of the electrolyte material is Li 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M is at least two of Mn, Co, and Ni elements, M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba, and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La, and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf, and Sn, M Ⅴ is at least one of Nb, Ta, V, and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, 0≤e≤0.6; The chemical formula of the electrolyte-modified lithium-rich manganese-based positive electrode material is xLi2MnO3 (1-x)LiMO2 αLi 3+2a+b-d+e [Zr 2-a-b-c-d M Ⅱ a M Ⅲ b M Ⅳ c M Ⅴ d ]Si 2+e P 1-e O 12 , and M is at least two of Mn, Co, and Ni elements, M Ⅱ is at least one of Cu, Mg, Zn, Mn, Ca, Ba, and Sr, M Ⅲ is at least one of Al, Sc, Ga, Y, La, and In, M Ⅳ is at least one of Ce, Ti, Ge, Hf, and Sn, M Ⅴ is at least one of Nb, Ta, V, and Sb, 0≤a≤0.3, 0≤b≤0.3, 0≤c≤0.3, 0≤d≤0.4, 0≤e≤0.6, 0≤α≤0.1, 0≤x≤1; A silicon source, a phosphorus source, a sodium source, a zirconium source, and a first metal source, a second metal source, a third metal source, a fourth metal source and a complexing agent are mixed to obtain a mixed solution; The mixed solution is evaporated by heating to obtain a gel, and then the gel is dried and dispersed to obtain an intermediate product; The intermediate product is calcined to obtain a precursor material; The precursor material is mixed with a lithium salt and a liquid carrier in an inert gas atmosphere, and then ion exchange reaction is carried out to obtain the electrolyte material; The first metal source is at least one of a copper source, a magnesium source, a zinc source, a manganese source, a calcium source, a palladium source and a strontium source, the second metal source is at least one of an aluminum source, a scandium source, a gallium source, a yttrium source, a lanthanum source and an indium source, the third metal source is at least one of a cerium source, a titanium source, a cadmium source, a hafnium source and a tin source, and the fourth metal source is at least one of a niobium source, an antimony source, a vanadium source and a tantalum source; The adding amount of the electrolyte material is 0-3% of the adding amount of the lithium-rich manganese-based positive electrode material in terms of mole percentage. The particle size of the electrolyte material is 100 nm to 2 um, and the specific surface area is 10 to 30 m 2 / g, and the conductivity of the electrolyte material is 0.1 to 5 mS / cm.

2. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 1, characterized in that, The sintering temperature is 300-700 DEG C, and the sintering time is 2-8 h.

3. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 2, characterized in that, The fluxing agent is at least one of B2O3, KF, BaCl2, CaCl2, LiCl, Na2B4O7, Li2B4O7, Na2BO3, NaCl, KCl and Li2BO2.

4. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 3, characterized in that, The step of calcining the intermediate product to obtain a precursor material comprises the following steps:

5. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 1, characterized in that, The intermediate product is calcined at a temperature of 800-1000 DEG C in an air atmosphere to obtain the precursor material. The ion exchange reaction temperature is 150-250 DEG C.

6. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 1, characterized in that, The liquid carrier is at least one of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium hexafluorophosphate.

7. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 1, characterized in that, The lithium salt is one of lithium hexafluorophosphate, lithium bis(trifluoromethylsulfonyl)imide, lithium bis(difluorosulfonyl)imide and lithium tetrafluoroborate.

8. The method for preparing the electrolyte-modified lithium-rich manganese-based cathode material according to claim 1, characterized in that, The lithium-rich manganese-based positive electrode material modified by the electrolyte is prepared by the preparation method of the lithium-rich manganese-based positive electrode material modified by the electrolyte.

9. A lithium-rich manganese-based positive electrode material modified with an electrolyte, characterized in that, ​

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