Positive electrode and preparation method therefor, and lithium secondary battery

A technology of positive electrode and positive electrode active material, which is applied in the direction of lithium battery, battery electrode, non-aqueous electrolyte battery, etc., can solve the problems of increasing the complexity of operation, and achieve the reduction of operating environment and operating process, excellent electrochemical cycle performance, and improvement of The effect of energy density

Inactive Publication Date: 2016-06-22
BYD CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0027] However, in the lithium-ion battery disclosed in CN102315422A, the lithium supplementary cathode needs to be taken out from the battery after the lithium source is provided, which increases the comp

Method used

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  • Positive electrode and preparation method therefor, and lithium secondary battery
  • Positive electrode and preparation method therefor, and lithium secondary battery

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preparation example Construction

[0080] Step (2) can be carried out under the operating conditions and environment of conventionally prepared positive electrodes of lithium secondary batteries. Generally, step (2) can be carried out in an air atmosphere. In step (2), the drying conditions can be selected conventionally. Specifically, the drying may be performed at a temperature of 60-120°C. The duration of the drying can be selected according to the drying temperature, generally 1-60 minutes, preferably 10-30 minutes.

[0081] Step (3) is used to form a positive electrode active material layer on the surface of the lithium supplement layer. It can be carried out under conventional processes and conditions. Specifically, the positive electrode active material, the second conductive agent, and the second binder can be dispersed in a solvent to form a positive electrode active material slurry, and the positive electrode active material slurry can be coated on the surface of the lithium-replenishing layer. In...

Embodiment 1

[0096] 1. Preparation of positive electrode

[0097] (1-1) Formation of Lithium Supplementary Layer

[0098] Will Li 3 P (purchased from Bailingwei Technology Co., Ltd.), conductive carbon black (purchased from Swiss Temego, the brand is superP) and polyvinylidene fluoride (purchased from Kynar, the brand is HSV900) are dispersed in N-methylpyrrolidone to form a lithium supplement slurry material. Among them, Li 3 P: Conductive carbon black: The weight ratio of polyvinylidene fluoride is 70:15:15, Li 3 The weight ratio of P:N-methylpyrrolidone is 100:40.

[0099] The lithium-replenishing slurry was coated on both sides of an aluminum foil (12 μm in thickness), and then dried at 100° C. for 10 minutes to form a lithium-replenishing layer on both sides of the aluminum foil (the single-layer thickness of the lithium-replenishing layer was 3 μm). Wherein, the total coating amount of the lithium-supplementing slurry is 0.5 g.

[0100] (1-2) Formation of positive electrode act...

Embodiment 2

[0109] Adopt the same method as Example 1 to prepare lithium secondary batteries, the difference is that in step (1-1), polyvinylidene fluoride uses an equivalent amount of polyvinylidene fluoride-hexafluoropropylene (available from Kynar, the trade mark is LBG-1) to prepare a lithium secondary battery.

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Abstract

The invention discloses a positive electrode and a preparation method therefor, and a lithium secondary battery employing the positive electrode. The positive electrode comprises a conductive substrate, a positive electrode active material layer and a lithium-compensating layer which is arranged between the conductive substrate and the positive electrode active material layer; the lithium-compensating layer comprises at least a kind of lithium-containing compound, at least a kind of conductive agent and at least a kind of binder; the lithium-containing compound is chosen from the group formed by the compound as shown in the formula Li<x>A, wherein A is O, P, S or N; and x is greater than 0 and less than or equal to 3. The positive electrode provided by the invention has the lithium-compensating function, and is capable of effectively compensating the irreversible capacity loss of the lithium secondary ion in the charging-discharging process and improving the energy density of the battery; the lithium secondary ion has excellent cycling performance and high-rate discharging performance; the positive electrode provided by the invention does not require metal lithium; compared with the battery adopting metal lithium, the severity on the operating environment and operation process is lowered; and therefore, the positive electrode provided by the invention can be prepared by a conventional process under conventional conditions.

Description

technical field [0001] The invention relates to a positive electrode and a preparation method thereof, and also relates to a lithium secondary battery using the positive electrode. Background technique [0002] Lithium secondary batteries using non-aqueous electrolytes have the advantages of high specific energy and low environmental pollution. Since Japan's Sony Corporation first launched commercial lithium secondary batteries in 1990, lithium secondary batteries have been widely used in electronic consumer products such as mobile phones, portable computers, and video cameras. With the continuous development of electronic product technologies such as smartphones and notebook computers, the energy density requirements for lithium secondary batteries are getting higher and higher. [0003] As we all know, for non-aqueous electrolyte lithium secondary batteries, during the first charge and discharge process of the battery, due to the formation of a solid electrolyte (ie, SEI ...

Claims

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Application Information

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IPC IPC(8): H01M4/13H01M4/139H01M10/052
CPCY02E60/10
Inventor 玉正日向红霞何珍刘卫平
Owner BYD CO LTD
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