Negative electrode of lithium ionic secondary battery and preparing method thereof

A negative electrode active material and lithium-ion battery technology, applied in secondary batteries, battery electrodes, active material electrodes, etc., can solve the problems of lack of cycle stability, poor cycle stability, and large volume expansion of alloys, and achieve high reversible intercalation Lithium capacity, high specific capacity, and improved cycle life

Inactive Publication Date: 2009-01-07
ADVANCED TECHNOLOGY & MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the amorphous structure is a metastable structure, which can be easily transformed into a crystalline state during repeated charge and discharge cycles, thus losing the advantages of the amorphous structure. Therefore, the alloys with the amorphous structure described in the above-mentioned patents lack cycle stability
[0007] Although the alloy negative electrode active material in the prior art has obtained a larger specific capacity than the carbon material negative electrode active material, it cannot solve the problem of large volume expansion and thus poor cycle stability.

Method used

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  • Negative electrode of lithium ionic secondary battery and preparing method thereof
  • Negative electrode of lithium ionic secondary battery and preparing method thereof
  • Negative electrode of lithium ionic secondary battery and preparing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] Metal tin and metal cobalt are melted to form a master alloy according to a mass ratio of 4:1, and put into a vacuum single-roller stripping device for strip making. The cooling roll speed is 27m / s. The prepared alloy strips are crushed to make coarse particles smaller than 1mm, and then the pre-alloyed coarse particles and graphite are mixed in a weight ratio of 4:1, and then put into a high-energy horizontal rotor ball mill with a protective atmosphere for grinding to prepare active Material. The grinding medium is a stainless steel grinding ball with a diameter of Φ5, and the ball-to-material ratio is 15:1; the protective atmosphere in the grinding chamber is argon, and the grinding method is alternating intermittent grinding with variable speed, that is: 600rpm for 24s, 1200rpm for 36s, after 10 cycles, Intermittent 10 minutes; accumulated grinding time 5h. Put the ground alloy powder into a vacuum heat treatment furnace with a protective atmosphere for heat treatm...

Embodiment 2

[0051] The negative electrode active material was prepared according to the situation of Example 1, except that the time for grinding the pre-alloy by the high-energy ball mill accumulated for 10 hours, and the negative electrode active material of Example 2 was obtained. The phase structure analysis of these alloy powders was carried out by using X-rays with Cu Kα rays as the radiation source, and the results showed that the alloy powders had an amorphous and nanocrystalline dual-phase structure.

[0052] Using the active material prepared in Example 2, a button-type simulated battery was prepared according to the situation in Example 1, and the performance of the battery was tested. It was found that the reversible capacity of the tin-based dual-phase alloy reached 509mAh / g in the first charge and discharge process, 20 times The capacity retention after cycling was 91%.

Embodiment 3

[0054] The negative electrode active material was prepared according to the situation of Example 1, except that the mass ratio of the SnCo pre-alloy was 3:1, and the negative electrode active material of Example 3 was obtained. The phase structure analysis of these alloy powders was carried out by using X-rays with Cu Kα rays as the radiation source, and the results showed that the alloy powders had an amorphous and nanocrystalline dual-phase structure.

[0055] Using the active material prepared in Example 3, a button-type simulated battery was prepared according to the situation in Example 1, and the performance of the battery was tested. It was found that the reversible capacity of the tin-based dual-phase alloy reached 498mAh / g in the first charge and discharge process, 20 times The capacity retention after cycling was 94%.

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Abstract

The invention provides a cathode active material of a lithium-ion battery, wherein, the cathode active material comprises a tin base alloy with an amorphous and nanocrystal dual-phase structure. The tin base alloy with the amorphous and nanocrystal dual-phase structure of the invention comprises tin (1); inactive elements (2) which are chosen from one or a plurality of the kinds of iron, cobalt, nickel, copper, titanium, manganese, vanadium and chromium and are not easy to be alloyed with the metal lithium; and carbon (3). The tin base dual-phase alloy of the invention has high specific capacity and good cycling; the maximum reversible capacity can reach 706Ah/g, and the capacity conservation rate keeps more than 96% after 20 cycles. In addition, the invention further provides a method for preparing the cathode active material.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, and more specifically relates to a lithium ion secondary battery negative electrode active material and a preparation method thereof. Background technique [0002] With the rapid development of portable electronic products and the urgent need for green and environmentally friendly power sources, lithium-ion batteries are developing in the direction of high energy density, high power density, high safety, long life, fast charging and discharging, and thin and light. In terms of negative electrode materials, the theoretical limit (372mAh / g) of lithium-ion specific capacity of widely used carbon materials has become a bottleneck in the development of lithium-ion batteries with high energy density, high power density and long life. Therefore, in recent years, the development of new anode materials has become a research focus and hotspot in this field. Among them, alloy materials whose specific c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38C22C13/00C22C1/02B22F9/00H01M4/02H01M10/40
CPCY02E60/122Y02E60/10
Inventor 刘志坚卢志超夏建华李德仁周少雄韩伟
Owner ADVANCED TECHNOLOGY & MATERIALS CO LTD
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