A kind of lithium ion battery negative plate and preparation method thereof

A technology for lithium ion batteries and negative electrode sheets, which is applied in battery electrodes, electrode manufacturing, electrode current collector coatings, etc., can solve the problems of large irreversible capacity of transition metal oxides, the cycle performance needs to be improved, and the coulombic efficiency is low. Suppression of capacity fluctuation, improvement of cycle stability, environment-friendly effect

Active Publication Date: 2020-07-17
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Li formed during the first discharge 2 O, it cannot be completely restored during the charging process, and there will be some Li 2 The existence of O, coupled with the irreversible SEI film formed during the first cycle, so the irreversible capacity of transition metal oxides is large, and the first Coulombic efficiency is low
Transition metal oxides also have large volume changes during the delithiation / intercalation process, which will cause particle crushing, so their cycle performance still needs to be improved.

Method used

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  • A kind of lithium ion battery negative plate and preparation method thereof
  • A kind of lithium ion battery negative plate and preparation method thereof
  • A kind of lithium ion battery negative plate and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Commercial Micron Size Fe 2 o 3 with commercial NaBO 2 4H 2 According to four ratios of molar ratio 1:0.1~0.4, in argon or air atmosphere, weigh the corresponding mass of Fe 2 o3 and NaBO 2 4H 2 0 is packed into the ball mill tank (as shown in table 1), the ball-to-material ratio is 60:1, and the ball mill beads are made of stainless steel; the planetary ball mill is used to mix the two, the ball mill speed is 300 rpm, and the ball mill time is 2 hours. A negative electrode active material sample was prepared.

[0040] The X-ray diffraction spectrum (XRD) of the ball milling product is characterized by figure 1 As shown, it can be seen that the mixture after mixing is composed of Fe 2 o 3 and NaBO 2 4H 2 O composition, indicating that ball milling only achieves Fe 2 o 3 with NaBO 2 4H 2 A physical mixture of O and no chemical reaction between the two.

[0041] Take 0.45 grams of ball milling product and 0.129 grams of acetylene black, add 2000 milliliters...

Embodiment 2

[0051] Take 0.45 g of the ball milling product of Example 1 and 0.129 g of acetylene black, mix and add 2000 ml of SA solution with a mass fraction of 1% wt, and coat and prepare pole pieces marked as Fe 2 o 3 -SA-1, Fe 2 o 3 -SA-2, Fe 2 o 3 -SA-3, Fe 2 o 3 -SA-4.

[0052] Figure 5 for commercial Fe 2 o 3 , Fe 2 o 3 -SA-1, Fe 2 o 3 -SA-2, Fe 2 o 3 -SA-3, Fe 2 o 3 -Charge cycle performance curve of SA-4. Visible, four different proportions containing NaBO 2 Fe for binder additives 2 o 3 Compared with the original Fe of the control group, the negative electrode material 2 o 3 The specific capacity and cycle stability of the pole piece have been greatly improved.

[0053] Control group: take Fe 2 o 3 Mix 0.45 g with 0.129 g of acetylene black, add 2000 ml of SA solution with a mass fraction of 1% wt, and coat to prepare pole pieces.

[0054] where Fe 2 o 3 -SA-2 has a specific discharge capacity of 1169.5 mAh per gram for the first time, a specific c...

Embodiment 3

[0057] Take 0.45 g of the ball milling product of Example 1 and 0.129 g of acetylene black, add 1000 ml of SA solution with a mass fraction of 1%wt and 1000 ml of CMC solution with a mass fraction of 1%wt, and coat and prepare pole pieces marked as Fe 2 o 3 -SC-1, Fe 2 o 3 -SC-2.

[0058] Control group: take Fe 2 o 3 Mix 0.45 g with 0.129 g of acetylene black, add 1000 ml of SA solution with a mass fraction of 1%wt and 1000 ml of CMC solution with a mass fraction of 1%wt, and coat to prepare pole pieces.

[0059] Figure 6 for commercial Fe 2 o 3 , Fe 2 o 3 -SC-1, Fe 2 o 3 -Charge cycle performance curve of SC-2. Visible, four different proportions containing NaBO 2 Fe for binder additives 2 o 3 Compared with the original Fe of the control group, the negative electrode material 2 o 3 The specific capacity and cycle stability have been greatly improved.

[0060] where Fe 2 o 3 -SC-2's first discharge specific capacity is 1256.9 mAh / g, charge specific capaci...

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Abstract

The invention discloses a negative electrode sheet of a lithium ion battery and a preparation method thereof. The method comprises the following steps: a sodium metaborate or a hydrate thereof is mixed with a metal oxide by ball milling to obtain a negative electrode active material; adding a conductive agent and the negative electrode active material into an aqueous binder for mixing to obtain anegative electrode slurry. The negative electrode slurry is coated on the negative electrode current collector and dried to obtain the negative electrode sheet of the lithium ion battery. Prior to adding the metal oxide to the binder, after ball milling with sodium metaborate or its hydrate, the anode piece of lithium ion battery can greatly improve the cycle stability of charge and discharge of the cathode material of lithium ion battery, restrain the capacity fluctuation phenomenon in the long-term cycle of metal oxide anode, and obtain stable capacity and long cycle life.

Description

technical field [0001] The invention relates to the field of lithium ion battery negative electrode materials, in particular to a lithium ion battery negative electrode sheet and a preparation method thereof. Background technique [0002] With the development of science and technology and the progress of human society, the problems of energy depletion and environmental pollution have become increasingly prominent. The development and utilization of renewable energy has become the basis for the sustainable development of human society in the 21st century. In chemical power sources, compared with traditional lead-acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries and other systems, lithium-ion batteries have high energy density, low self-discharge rate, long cycle life, wide temperature range, no memory response, green and Pollution and other advantages have been widely used in mobile communications, notebook computers, small cameras and other electrical equip...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/1391H01M4/62H01M4/04H01M4/131
CPCH01M4/0404H01M4/131H01M4/1391H01M4/621H01M4/624H01M4/628Y02E60/10
Inventor 刘永锋曲晓雷潘洪革高明霞
Owner ZHEJIANG UNIV
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