Ternary positive electrode material@titanium nitride core-shell-structured composite material and preparation method thereof

A technology of cathode material and core-shell structure, which is applied in the field of cathode materials for lithium-ion batteries, can solve problems such as the inability to fully improve the overall performance of the composite, difficulty in ensuring the uniformity of the coating layer, and the impact of conductivity and ion conductivity. Achieve the effects of easy regulation of TiN content, low cost, and low battery internal resistance

Active Publication Date: 2021-07-09
TSINGHUA UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the existing methods have the following problems: 1) The coating uniformity of the coating layer prepared by physical mixing and sintering is difficult to guarantee, which will affect the inhibitory effect on the expansion of the internal active material, and at the same time cannot prevent the side reactions caused by contact with the external electrolyte. Affect the cycle performance; 2) The conductivity and ion conductivity of the amorphous coating layer are significantly affected due to insufficient crystallinity, which cannot fully improve the overall performance of the composite

Method used

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  • Ternary positive electrode material@titanium nitride core-shell-structured composite material and preparation method thereof
  • Ternary positive electrode material@titanium nitride core-shell-structured composite material and preparation method thereof
  • Ternary positive electrode material@titanium nitride core-shell-structured composite material and preparation method thereof

Examples

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Effect test

Embodiment 1

[0064] A certain amount of high-purity NCM powder is placed in a fluidized bed reactor for 500h -1 Ar gas was introduced at a space velocity of 100mL / min to keep the powder in a fully fluidized state, and then the temperature inside the reactor was raised to 900°C at 10°C / min; the TiCl carried by Ar was 4 steam and water vapor with TiCl 4 :H 2 The ratio of O=1:8, preheated to 150°C, respectively introduced into the fluidized bed for deposition reaction, in which TiCl 4 :Ar=1:7、H 2 O:Ar=1:15, the total space velocity of the two gases is 500h -1 . Stop feeding TiCl after 3h 4 Steam and water vapor, replaced by Ar and kept heating for 10min, then naturally cooled to room temperature to obtain the intermediate product NCM@TiO 2 .

[0065] The intermediate product NCM@TiO 2 Place in a fluidized bed reactor and heat until the system temperature rises to 800°C; pure N 2 The gas is introduced into the fluidized bed at 650mL / min to carry out the conversion reaction, and the in...

Embodiment 2

[0084] A certain amount of high-purity NCM powder is placed in a fluidized bed reactor for 500h -1 Ar gas was introduced at a space velocity of 300mL / min to keep the powder in a fully fluidized state, and then the temperature inside the reactor was raised to 900°C at 15°C / min; the TiCl carried by Ar was 4 steam and water vapor with TiCl 4 :H 2 The ratio of O=1:8, preheated to 200°C, respectively introduced into the fluidized bed for deposition reaction, in which TiCl 4 :Ar=1:7,H 2 O:Ar=1:15, the total space velocity of the two gases is 500h -1 . Stop feeding TiCl after 3h 4 Steam and water vapor, replaced by Ar and kept heating for 15min, then naturally cooled to room temperature to obtain the intermediate product NCM@TiO 2 .

[0085] The intermediate product NCM@TiO 2 Place in a fluidized bed reactor and heat until the system temperature rises to 800°C; pure N 2 The gas is introduced into the fluidized bed at 650mL / min to carry out the conversion reaction, and the in...

Embodiment 3

[0087] A certain amount of high-purity NCA powder is placed in the fluidized bed reactor for 800h -1 Ar gas was introduced at a space velocity of 500mL / min to keep the powder in a fully fluidized state, and then the temperature inside the reactor was raised to 1100°C; the TiCl carried by Ar was 4 steam and water vapor with TiCl 4 :H 2 The ratio of O=1:10, preheated to 300°C, respectively introduced into the fluidized bed for deposition reaction, in which TiCl 4 :Ar=1:2, H 2 O:Ar=1:30, the total space velocity of the two gases is 800h -1 . Stop feeding TiCl after 4h 4 steam and water vapor, replaced by Ar and kept heating for 30min, then naturally cooled to room temperature to obtain the intermediate product NCA@TiO 2 .

[0088] The intermediate product NCA@TiO 2 Place in a fluidized bed reactor and heat until the system temperature rises to 1000°C; pure NH 3 The gas is introduced into the fluidized bed at 800mL / min to carry out the conversion reaction, and the introdu...

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Abstract

The invention discloses a ternary positive electrode material@titanium nitride core-shell-structured composite material, belonging to the technical field of positive electrode materials of lithium ion batteries. The composite material is of a compact double-layer structure, wherein the inner layer is a nickel-cobalt-aluminum or nickel-cobalt-aluminum ternary positive electrode material, and the outer layer is a high-crystallinity titanium oxide TiN; on the basis that the total weight of the composite material is 100%, the mass fraction of the inner layer is 30-95%, and the mass fraction of the outer layer is 5-70%; and the outer layer is TiN with high crystallinity, the crystallinity of the outer layer is not lower than 90%, and the purity of the outer layer is not lower than 99.5%. In addition, the invention also discloses a preparation method of the composite material. Compared with an original ternary positive electrode material which is not subjected to coating treatment, the composite material of the invention has the characteristics of remarkably improved conductivity, relatively high specific capacity, good cycling stability, improved rate capability and reduced internal resistance. The preparation method is simple in process, free of pollution, low in cost, short in flow and easy for industrial amplification.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery cathode materials, in particular to a ternary cathode material@titanium nitride core-shell structure composite material and a preparation method thereof, which can be used for lithium-ion battery cathode materials. Background technique [0002] In recent years, layered transition metal oxide cathode materials, Li[Ni x co y mn z ](NCM) and Li[Ni x co y al z ] (NCA) ternary cathode has gradually replaced the traditional LCO cathode material and is widely used in the field of commercial lithium-ion power batteries. With further requirements on battery energy density and cost, the Ni content has been gradually increased to over 60% for ternary cathode materials. However, high Ni content will lead to instability of crystal structure and increase of anisotropic volume expansion due to weak Ni-O bond interaction, resulting in poor overall cycle life, poor discharge ability at high curre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/505H01M4/525H01M4/58H01M10/0525
CPCH01M4/366H01M4/505H01M4/525H01M4/58H01M10/0525Y02E60/10
Inventor 肖哲熙魏飞张晨曦于春辉
Owner TSINGHUA UNIV
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