Modification method of silicon negative electrode material for lithium ion battery

A lithium-ion battery, silicon anode technology, applied in battery electrodes, negative electrodes, secondary batteries, etc., can solve the problems of silicon material pulverization, affecting cycle performance, etc., to improve conductivity, simple and effective preparation methods, and reduce volume. inflated effect

Pending Publication Date: 2020-04-10
SHANGHAI NAT ENG RES CENT FORNANOTECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Silicon has attracted attention due to its high theoretical specific capacity. Compared with traditional graphite negative electrodes, silicon negative electrodes have obvious advantages in specific capacity; silicon is the second most abundant element in the earth's crust, and its abundant reserves make it a sufficient source of raw materials. However, the silicon negative electrode material will produce a large volume change during the process of lithium ion insertion and extraction, which will cause the pulverization of the silicon material and affect the cycle performance.

Method used

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  • Modification method of silicon negative electrode material for lithium ion battery
  • Modification method of silicon negative electrode material for lithium ion battery

Examples

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Effect test

Embodiment 1

[0016] A modification method of silicon negative electrode material for lithium ion battery, according to the following steps:

[0017] Using 1g of nano-silica powder and 10g of tetrabutyl titanate as raw materials, react under hydrothermal conditions at 150°C for 12 hours, filter and dry to obtain a precursor; After mixing evenly, the carbon / nitrogen source used is one of guanidine hydrochloride and urea. Under a nitrogen atmosphere, the temperature was raised to 900°C at a heating rate of 5°C / min, kept for 2 hours, and then naturally cooled to room temperature to obtain a multilayer structure. silicon-based anode material.

[0018] The first charge and discharge efficiency graph of the preparation of silicon-based negative electrode materials is shown in figure 1 , and the cycle performance graph see figure 2 , the cycle performance is significantly improved.

Embodiment 2

[0020] A modification method of silicon negative electrode material for lithium ion battery, similar to embodiment 1, according to the following steps:

[0021] Take 1g of nano-silica powder and 10g of tetrabutyl titanate as raw materials, react at 180°C for 12 hours under hydrothermal conditions, filter and dry to obtain a precursor; then mix the precursor and carbon / nitrogen source at a mass ratio of 1:8 The ratio was mixed evenly, and the temperature was raised to 900°C at a heating rate of 8°C / min under a nitrogen atmosphere, kept for 2 hours, and then naturally cooled to room temperature.

Embodiment 3

[0023] A modification method of silicon negative electrode material for lithium ion battery, similar to embodiment 1, according to the following steps:

[0024] Take 1g of nano-silica powder and 10g of tetrabutyl titanate as raw materials, react under hydrothermal conditions of 200°C for 12h, filter and dry to obtain the precursor. Then the precursor and carbon / nitrogen source were mixed evenly at a mass ratio of 1:10, and the temperature was raised to 900 °C at a heating rate of 10 °C / min in a nitrogen atmosphere, kept for 2 h, and then naturally cooled to room temperature.

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Abstract

The invention relates to a modification method of a silicon negative electrode material of a lithium ion battery, which is characterized by comprising the following steps: by taking nano silicon powder and tetrabutyl titanate as raw materials, reacting under a hydrothermal condition, filtering and drying to obtain a precursor; and uniformly mixing the precursor and a carbon / nitrogen source according to a certain ratio, and carrying out heat treatment to obtain the two-layer coated silicon negative electrode lithium ion battery material which takes silicon nanoparticles as a core, takes a titanium nitride layer as a middle layer and takes a carbon layer as an outermost layer. The preparation method provided by the invention is simple and effective, and the prepared silicon-based negative electrode material has a carbon layer with good conductivity and a titanium nitride layer with a stable structure in a lithium ion deintercalation process, so that volume expansion of silicon in a charging and discharging process can be effectively slowed down. The core is elemental silicon with high specific capacity. Therefore, the material has good lithium storage performance.

Description

technical field [0001] The invention relates to a method for modifying a negative electrode material of a lithium ion battery, in particular to a method for modifying a silicon-based negative electrode material for a lithium ion battery. [0002] technical background [0003] Lithium-ion batteries are widely used due to their advantages such as large specific energy, long cycle life, stable discharge voltage, wide operating temperature range, low self-discharge rate and no memory effect. [0004] In recent years, people have been looking for ways to increase the specific energy of lithium-ion batteries. Silicon has attracted attention due to its high theoretical specific capacity. Compared with traditional graphite negative electrodes, silicon negative electrodes have obvious advantages in specific capacity; silicon is the second most abundant element in the earth's crust, and its abundant reserves make it a sufficient source of raw materials. However, the silicon negative e...

Claims

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Application Information

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IPC IPC(8): H01M4/38H01M4/04H01M10/0525
CPCH01M4/386H01M4/0471H01M10/0525H01M2004/027Y02E60/10
Inventor 崔大祥王亚坤张芳张道明卢玉英阳靖峰焦靖华张放为葛美英
Owner SHANGHAI NAT ENG RES CENT FORNANOTECH
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