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Fluorine-free preparation method for three-dimensional porous silica powder anode material of lithium ion battery

A lithium-ion battery, three-dimensional porous technology, applied in the field of electrochemical power supply, can solve the problems of hydrofluoric acid toxicity and strong corrosiveness, and achieve the effects of improved material specific capacity and cycle stability, easy operation, and low material preparation cost

Active Publication Date: 2013-05-08
CHINA THREE GORGES UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The preparation of porous silicon film is realized by electrochemical anodic oxidation or chemical etching process. Both processes use hydrofluoric acid to preferentially corrode the specific crystal direction of single crystal silicon to realize the growth of pores, and the method of creating pores on polycrystalline silicon particles less research
On the other hand, hydrofluoric acid is highly toxic and corrosive, and has high requirements for experimental operations.

Method used

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  • Fluorine-free preparation method for three-dimensional porous silica powder anode material of lithium ion battery
  • Fluorine-free preparation method for three-dimensional porous silica powder anode material of lithium ion battery
  • Fluorine-free preparation method for three-dimensional porous silica powder anode material of lithium ion battery

Examples

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Effect test

Embodiment 1

[0042] Example 1. Prepare the lithium ion battery three-dimensional porous silicon powder anode material according to the preparation example method, set the decomposition temperature of magnesium silicide to 800° C., and other conditions are in accordance with the preparation example scheme. The obtained porous silicon material is prepared for the electrochemical test. The electrode preparation method, battery assembly and test conditions are the same as those in Comparative Example 1. The first lithium insertion capacity of the material is 2883.3mAh / g, the delithiation capacity is 1821.0mAh / g, and the coulombic efficiency is 63.2%. The 10th cycle has a lithium insertion capacity of 123.0mAh / g and a delithiation capacity of 119.0mAh / g, its capacity retention rate is 6.53%, and the capacity attenuation is large. The relatively pure nano-silicon electrode material has poor electrochemical performance. At this temperature, the decomposition of magnesium silicide is insufficient...

Embodiment 2

[0043] Example 2. The three-dimensional porous silicon powder anode material for lithium ion batteries was prepared according to the preparation example method, the decomposition temperature of magnesium silicide was set to 900° C., and the other conditions were in accordance with the preparation example scheme. The obtained porous silicon material is prepared for the electrochemical test. The electrode preparation method, battery assembly and test conditions are the same as those in Comparative Example 1. The material has a first lithium insertion capacity of 2007.8mAh / g, a delithiation capacity of 1185.0mAh / g, and a coulombic efficiency of 59.0%. The 10th cycle lithium insertion capacity was 529.6mAh / g, the delithiation capacity was 507.8mAh / g, and its capacity retention rate was 42.85%. After 70 cycles, the lithium insertion capacity is 211.7 mAh / g, the delithiation capacity is 214.0 mAh / g, and the capacity retention rate is 18.06%. Relatively pure nano-silicon electrode m...

Embodiment 3

[0044] Example 3. Prepare the lithium ion battery three-dimensional porous silicon powder anode material according to the preparation example method, set the decomposition temperature of magnesium silicide to 1000° C., and other conditions are in accordance with the preparation example scheme. The obtained porous silicon material is prepared for the electrochemical test. The electrode preparation method, battery assembly and test conditions are the same as those in Comparative Example 1. The first lithium insertion capacity of the material is 2184.1mAh / g, the first delithiation capacity is 1296.8mAh / g, and the coulombic efficiency is 59.4%. After 10 cycles, the material can still release a reversible capacity of 596.8mAh / g, and the capacity retention rate is 46.02%. After 70 cycles, its lithium insertion capacity is 261.0 mAh / g, its delithiation capacity is 258.2 mAh / g, and its capacity retention rate is 19.9%. The electrochemical performance of relatively pure nano-silicon e...

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Abstract

The invention discloses a fluorine-free preparation method for a three-dimensional porous silica powder anode material of a lithium ion battery. In the method, combination reaction is performed on ordinary micron-sized silicon and magnesium particles to generate magnesium silicide, and the magnesium silicide is pyrolyzed at high temperature to form magnesium vapor and silica powder with a three-dimensional porous structure. By the fluorine-free preparation method for the three-dimensional porous silica powder anode material of the lithium ion battery, a preparation process is free from fluorine so as to avoid environmental pollutions; the material has the porous structure so as to realize the self-absorption of volume effects of the silicon particles; the specific capacity and recycling stability of the material are improved to a certain extent; and a synthesis process is simple and easy to operate, and the preparation cost of the material is low.

Description

Technical field [0001] The invention belongs to the field of electrochemical power supplies, and specifically relates to a method and technology for preparing a porous silicon negative electrode material for a lithium ion battery. Background technique [0002] In addition to carbon anode materials in anode research, many researches focus on metals (such as Al, Zn, Cu, Sn, etc.), semiconductors (Si), and metal oxides (such as CoO, Co 3 O 4 , Cu 2 O, NiO, FeO, SnO, SiOx), phosphide (Sn 4 P 3 ), lithium transition metal nitride Li 3-x M x N (M is Co, Cu, Ni) and phosphide Li 7 MP 4 (M is Ti, V, Mn) and other materials. The first cycle efficiency of metal oxides is low, and the lithium removal potential is too high; lithium transition metal nitrides may decompose to produce nitrogen when short-circuit or overdischarge; and lithium-intercalated phosphides release toxic gas phosphine in the air, which is safe Hidden dangers. For lithium alloys, the volume effect causes the battery cap...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/1395
CPCY02E60/10
Inventor 杨学林石长川余德馨王凤军
Owner CHINA THREE GORGES UNIV
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