Preparation method of titanium dioxide-doped high-nickel ternary positive electrode material and solid-state lithium ion battery

Abstract

The invention provides a preparation method of a titanium dioxide-doped high-nickel ternary positive electrode material and a solid-state lithium ion battery. LiOH.H2O, a high-nickel ternary precursor Ni0. 9Co0. 05Mn0. 05 (OH) 2 and titanium dioxide are put into a mortar to be ground and then put into a corundum crucible, the corundum crucible is fed into a tubular furnace, and high-temperature sintering is performed in an oxygen atmosphere; and taking out the sintered sample, cooling to room temperature, and then grinding to obtain the treated high-nickel ternary positive electrode material. LiOH and Li2CO3 remained in the sintering process of the high-nickel ternary positive electrode material consumed by titanium dioxide are utilized to form titanium ions with high ion conductivity to coat the surface of the high-nickel ternary positive electrode material in situ; and meanwhile, Ti < 4 + > with high valence state is doped into the bulk phase of the high internal ternary positive electrode material, so that a serious interface reaction between the solid-state battery positive electrode material and an electrolyte can be well solved, and the stability of the positive electrode material in battery circulation is kept.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a preparation method of a high-nickel ternary positive electrode material doped with titanium dioxide and a solid-state lithium ion battery. BACKGROUND

[0002] Lithium ion batteries have been widely applied in the fields of electronic products and electric vehicles due to their excellent performance, however, currently, commercial liquid lithium ion batteries still have many defects, such as that the energy density, current density, environmental compatibility and price do not meet the expected requirements. In addition, the use of organic electrolyte can cause fire hazards. In order to solve these problems, all-solid-state lithium ion batteries (ASSLIB) with high energy density and high safety on the basis of metal lithium anodes have become a research hotspot in recent years.

[0003] Although the all-solid-state lithium ion battery (ASSLIB) has a good development prospect, but at present, it still faces great difficulties in practical application. On the positive electrode side interface, the solid-state battery faces serious interface reaction between the positive electrode material and the solid-state electrolyte, and problems such as space charge layer, element diffusion, poor contact and the like are generated; on the positive electrode material itself, the particle is broken, and the internal particles are isolated, which leads to high interface impedance and continuous capacity attenuation of the solid-state battery. SUMMARY

[0004] In view of the defects of the prior art, the application provides a preparation method of a high-nickel ternary positive electrode material doped with titanium dioxide and a solid-state lithium ion battery, and the application utilizes titanium dioxide to consume residual LiOH and Li2CO3 in the sintering process of the high-nickel ternary positive electrode material, to form in-situ coating of the high-nickel ternary positive electrode material surface with high ion conductivity, and to simultaneously dope Ti4 + Doping into the high-nickel ternary positive electrode material body phase can well solve the serious interface reaction between the solid-state battery positive electrode material and the electrolyte, and maintain the stability of the positive electrode material in the battery cycle.

[0005] The technical scheme of the application is as follows: a preparation method of a high-nickel ternary positive electrode material doped with titanium dioxide, comprising the following steps: S1), weighing high-nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)2, LiOH·H2O and titanium dioxide in an argon-filled glove box, and grinding in a mortar until uniform; S2), placing the mixed material ground in step S1) in a corundum crucible, and sending into a tube furnace for high-temperature sintering under an oxygen atmosphere; S3), taking out the sintered sample, immediately transferring to the glove box, cooling to room temperature, and then grinding to obtain the treated high-nickel ternary positive electrode material.

[0006] Preferably, in step S1), the molar fraction of the titanium dioxide in the mixed material is 0.5-5%.

[0007] Preferably, in step S1), the molar fraction of the high-nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)2 in the mixed material is 49.75-47.5%.

[0008] Preferably, in step S1), the molar fraction of the LiOH·H2O in the mixed material is 49.75-47.5%.

[0009] Preferably, in step S1), the grinding time is not less than 30 min.

[0010] Preferably, in step S2), the high-temperature sintering temperature is 800℃, and the temperature is raised to 800℃ at a temperature rising rate of 5℃ / min; the sintering time is 12h.

[0011] Preferably, in step S3), the grinding time is not less than 30 min.

[0012] Preferably, in step S3), the high-nickel ternary positive electrode material is a high-nickel ternary positive electrode material with in-situ coated interface and titanium doping, and the titanium dioxide is consumed to form a titanium ion in-situ coated high-nickel ternary positive electrode material surface with high ion conductivity, and Ti4 + with high valence is doped into the bulk phase of the high-nickel ternary positive electrode material.

[0013] Preferably, the application further provides a solid-state lithium ion battery, which comprises a positive electrode material, an electrolyte, conductive carbon and a negative electrode material; the positive electrode material is a high-nickel ternary positive electrode material doped with titanium dioxide. The positive electrode material, the electrolyte and the conductive carbon are put into a mortar in a certain mass ratio and ground to form a mixed positive electrode material, and then the mixed positive electrode material, the conductive carbon and the negative electrode material are added to a mold to press a solid-state lithium ion battery.

[0014] Preferably, the electrolyte is lithium phosphorus sulfur chloride electrolyte LPSCL; the conductive carbon is Super P; and the negative electrode material is lithium-indium alloy.

[0015] As preferred, the positive electrode material: electrolyte: conductive carbon is put into a mortar at a mass ratio of 150:100:5, and is ground for 30 min to prepare a mixed positive electrode material.

[0016] The present application has the following beneficial effects: 1. The present application uses titanium dioxide to consume residual LiOH and Li2CO3 in the sintering process of high-nickel ternary positive electrode materials, to form in-situ coating of the surface of high-nickel ternary positive electrode materials with high ionic conductivity, and to simultaneously form Ti 4+ Doping into the bulk phase of high-nickel ternary positive electrode materials can well solve the serious interface reaction between the positive electrode material and the electrolyte of the solid-state battery, while maintaining the stability of the positive electrode material in the battery cycle; 2. The high-nickel ternary positive electrode material of the present application has good long cycle stability, excellent rate performance and extremely high energy density in the full-solid-state lithium ion battery based on sulfide electrolyte, and provides a new idea for the modification method of the positive electrode of the solid-state battery and the realization of high-energy-density solid-state batteries. 3. The process of the present application is simple, pollution-free, and easy to mass-produce, and the reaction is stable. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The XRD graph of the high-nickel ternary positive electrode material prepared for Example 1, Example 2, Example 3 and Comparative Example 1 of the present application; Figure 2 The sample Sem graph of the high-nickel ternary positive electrode material prepared for Example 2 of the present application; Figure 3 The particle size distribution graph of the high-nickel ternary positive electrode material prepared for Example 2 of the present application; Figure 4 The Mapping graph of the high-nickel ternary positive electrode material prepared for Example 2 of the present application; Figure 5 The 100-cycle long cycle performance graph of the full-solid-state lithium ion battery based on LPSCL electrolyte of the high-nickel ternary positive electrode material treated with titanium dioxide prepared for Example 2 of the present application at a current density of 0.2C and a high voltage of 4.5V; Figure 6 The 100-cycle long cycle performance graph of the full-solid-state lithium ion battery based on LPSCL electrolyte of the high-nickel ternary positive electrode material treated with titanium dioxide prepared for Example 2 of the present application at a current density of 0.5C and a high voltage of 4.55V; Figure 7 The rate performance graph of the battery based on LPSCL electrolyte of the high-nickel ternary positive electrode material treated with titanium dioxide prepared for Example 1, Example 2, Example 3 and Comparative Example 1 of the present application at 4.55V. DETAILED DESCRIPTION

[0018] The specific embodiments of the present application are further described below with reference to the accompanying drawings: Example 1 The present embodiment provides a preparation method of a high-nickel ternary positive electrode material, specifically comprising the following steps: S1), 10g of high-nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)2, 4.86g of LiOH H2O and 0.5% of titanium dioxide in terms of molar fraction of the mixed material are placed in a mortar and ground until uniform; S2), the mixed material ground in step S1) is placed in a corundum crucible and sent into a tube furnace for sintering, an oxygen atmosphere is maintained during sintering, the temperature is raised to 800°C at a heating rate of 5°C / min, and the total heating time is 156 min; after heating is completed, sintering is continued at 800°C for 12h; S3), the sintered sample is immediately transferred to an argon-filled glove box, and after cooling to room temperature, it is taken out and ground in a mortar, the grinding time is 30 min, and a titanium dioxide treated high-nickel ternary positive electrode material Ti-NCM9055 is obtained.

[0019] According to the mass ratio of high-nickel ternary positive electrode material Ti-NCM9055: lithium phosphorus sulfur chloride electrolyte LPSCL: conductive carbon Super P is 150:100:5, put into the mortar and grind for 30min to make mixed positive electrode material; then according to the mixed positive electrode material 5mg, LPSCL is 250mg, lithium indium alloy as negative electrode, add into the mold and press into solid-state lithium ion battery.

[0020] Example 2 The present embodiment provides a preparation method of a high-nickel ternary positive electrode material, specifically comprising the following steps: S1), 10g of high-nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)2, 4.86g of LiOH H2O and 0.5% of titanium dioxide in terms of molar fraction of the mixed material are placed in a mortar and ground until uniform; S2), the mixed material ground in step S1) is placed in a corundum crucible and sent into a tube furnace for sintering, an oxygen atmosphere is maintained during sintering, the temperature is raised to 800°C at a heating rate of 5°C / min, and the total heating time is 156 min; after heating is completed, sintering is continued at 800°C for 12h; S3), the sintered sample was immediately transferred to an argon-filled glove box, and after cooling to room temperature, it was taken out and poured into a mortar for grinding. The grinding time was 30 min, and a titanium dioxide treated high nickel ternary positive electrode material Ti-NCM9055 was obtained.

[0021] According to the mass ratio of high nickel ternary positive electrode material Ti-NCM9055: lithium phosphorus sulfur chloride electrolyte LPSCL: conductive carbon Super P 150:100:5, put into a mortar and grind for 30 min to make a mixed positive electrode material; then according to the mixed positive electrode material 5 mg, LPSCL is 250 mg, lithium indium alloy as negative electrode, add into the mold and press into solid state lithium ion battery.

[0022] Example 3 The embodiment provides a preparation method of a high nickel ternary positive electrode material, which specifically comprises the following steps: S1), in an argon-filled glove box, 10 g of high nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)2, 4.86 g of LiOH·H2O and 1% of titanium dioxide based on the molar fraction of the mixed material were placed in a mortar and ground for more than 30 min until uniform grinding; S2), the ground mixed material in step S1) was placed in a corundum crucible and sent into a tube furnace for sintering. An oxygen atmosphere was maintained during sintering, and the temperature was raised to 800°C at a rate of 5°C / min, and the total heating time was 156 min. After heating, the sintering was maintained at 800°C for 12 h. S3), the sintered sample was immediately transferred to an argon-filled glove box, and after cooling to room temperature, it was taken out and poured into a mortar for grinding. The grinding time was 30 min, and a titanium dioxide treated high nickel ternary positive electrode material Ti-NCM9055 was obtained.

[0023] According to the mass ratio of high nickel ternary positive electrode material Ti-NCM9055: lithium phosphorus sulfur chloride electrolyte LPSCL: conductive carbon Super P 150:100:5, put into a mortar and grind for 30 min to make a mixed positive electrode material; then according to the mixed positive electrode material 5 mg, LPSCL is 250 mg, lithium indium alloy as negative electrode, add into the mold and press into solid state lithium ion battery.

[0024] Comparative Example 1 S1), in an argon-filled glove box, 10 g of high nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 (OH)2, 4.86 g of LiOH·H2O were placed in a mortar and ground for more than 30 min until uniform grinding; S2), the mixed material ground in step S1) is placed in a corundum crucible and sent into a tube furnace for sintering, an oxygen atmosphere is maintained during sintering, the temperature is raised to 800°C at a temperature raising rate of 5°C / min, and the temperature raising is performed for 156 min in total; after the temperature raising is completed, sintering is maintained at 800°C for 12 h; S3), the sintered sample is immediately transferred into an argon-filled glove box, and after being cooled to room temperature, the sample is taken out and ground in a mortar for 30 min to obtain a titanium dioxide treated high-nickel ternary positive electrode material bare-NCM9055.

[0025] The high-nickel ternary positive electrode material bare-NCM9055, lithium phosphorus sulfur chloride electrolyte LPSCL, and conductive carbon Super P are mixed in a mass ratio of 150:100:5, ground in a mortar for 30 min to prepare a mixed positive electrode material; then, the mixed positive electrode material 5 mg, LPSCL 250 mg, and lithium-indium alloy as a negative electrode are added into a mold and pressed into a solid-state lithium ion battery.

[0026] Example 4 In this example, the positive electrode materials and batteries prepared in Examples 1-3 and Comparative Example 1 are analyzed, and the analysis results are shown in Table 1. Figures 1-7 As shown in Table 1, Figure 1 It can be seen from the XRD that the ratio of the 003 peak to the 104 peak of Example 2 is appropriate, indicating that the lithium-nickel mixing arrangement is reduced, and the appearance of the layered structure can be clearly seen; and from Figure 2 , 3 It can be seen that the crystal grain size is relatively uniform, and is maintained at 4-4.5 microns; from Figure 4 It can be seen that Ti is uniformly doped in the material; from Figure 5 It can be seen that the battery has a retention rate of 95.69% after 100 cycles at a current density of 0.2C and a high voltage of 4.5V; from Figure 6 It can be seen that the battery has a retention rate of 96.32% after 100 cycles at a current density of 0.5C and a high voltage of 4.55V; from Figure 7 It can be seen that Example 2 has the highest discharge capacity at a current density of 0.1C, 0.2C, 0.5C, 1C, and 2C and a high voltage of 4.55V.

[0027] The above examples and descriptions in the specification are only to illustrate the principles and the best mode of the present application, and various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application.

Claims

1. A method for preparing a high-nickel ternary cathode material doped with titanium dioxide, characterized in that, Includes the following steps: S1) Weigh out the high-nickel ternary precursor Ni in an argon-filled glove box. 0.9 Co 0.05 Mn 0.05 (OH)2, LiOH·H2O and titanium dioxide are placed in a mortar and ground until uniform; S2) Place the ground mixture from step S1) into an alumina crucible and send it into a tube furnace for high-temperature sintering in an oxygen atmosphere. S3) Take out the sintered sample and immediately transfer it to a glove box. After cooling to room temperature, grind it to obtain the processed high-nickel ternary cathode material.

2. The method for preparing a high-nickel ternary cathode material doped with titanium dioxide according to claim 1, characterized in that: In step S1), the titanium dioxide accounts for 0.5-5% of the molar fraction of the mixed material.

3. The method for preparing a high-nickel ternary cathode material doped with titanium dioxide according to claim 1, characterized in that: In step S1), the high-nickel ternary precursor Ni 0.9 Co 0.05 Mn 0.05 The molar fraction of (OH)2 in the mixed materials is 49.75-47.5%.

4. The method for preparing a high-nickel ternary cathode material doped with titanium dioxide according to claim 1, characterized in that: In step S1), the molar fraction of LiOH·H2O in the mixed material is 49.75-47.5%.

5. The method for preparing a high-nickel ternary cathode material doped with titanium dioxide according to claim 1, characterized in that: In steps S1) and S3), the grinding time is not less than 30 minutes.

6. The method for preparing a high-nickel ternary cathode material doped with titanium dioxide according to claim 1, characterized in that: In step S2), the high-temperature sintering temperature is 800℃, and the temperature is increased to 800℃ at a heating rate of 5℃ / min; the sintering time is 12h.

7. The method for preparing a high-nickel ternary cathode material doped with titanium dioxide according to claim 1, characterized in that: In step S3), the high-nickel ternary cathode material is a high-nickel ternary cathode material with an in-situ coating interface and titanium doping. The titanium dioxide consumed during the sintering process of the high-nickel ternary cathode material by LiOH and Li2CO3 residuals forms titanium ions with high ionic conductivity that in-situ coat the surface of the high-nickel ternary cathode material, and the high-valence Ti4+ is coated with titanium ions. + Doping is incorporated into the bulk phase of the high-internal ternary cathode material.

8. A solid-state lithium-ion battery, comprising a positive electrode material, an electrolyte, conductive carbon, and a negative electrode material; characterized in that, The cathode material is a high-nickel ternary cathode material doped with titanium dioxide prepared by the method described in any one of claims 1-7; The positive electrode material, electrolyte, and conductive carbon are ground in a mortar in a certain mass ratio to form a mixed positive electrode material. Then, the mixed positive electrode material, conductive carbon, and negative electrode material are added to a mold and pressed into a solid lithium-ion battery.

9. A solid-state lithium-ion battery according to claim 8, characterized in that: The electrolyte is lithium phosphorus sulfur chloride electrolyte (LPSCL); the conductive carbon is Super P; and the negative electrode material is lithium indium alloy.

10. A solid-state lithium-ion battery according to claim 8, characterized in that, The positive electrode material, electrolyte, and conductive carbon are ground in a mortar at a mass ratio of 150:100:5 for 30 minutes to prepare a mixed positive electrode material.

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