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Method for preparing lithium manganate anode material with low SO4<2-> content

A positive electrode material, lithium manganate technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problems of increased polarization, reduced reversibility, and unstable lattice of positive electrode materials, and achieves improved cycle performance and battery performance. Stable, easy-to-use effects

Inactive Publication Date: 2013-12-11
HUNAN CHEM RES INST
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  • Summary
  • Abstract
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  • Claims
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Problems solved by technology

However, due to problems such as manganese dissolution, crystal lattice instability and John-Teller effect, the cycle performance, high temperature performance and storage performance of lithium manganate batteries are poor, which restricts the development of lithium manganate as a cathode material for lithium ion batteries. major factor
Many researchers at home and abroad have done a lot of work on this, trying to improve the performance of lithium manganate through anion doping, metal ion doping and surface coating, but the effect is not obvious.
[0003] Studies have shown that SO in lithium manganese oxide materials 4 2- The presence of will promote the decomposition of lithium manganate to produce Li 2 SO 4 and Mn 2 o 3 Impurities increase the polarization of positive electrode materials, reduce reversibility, and deteriorate cycle performance, especially high-temperature cycle performance and storage performance.
At present, the raw materials for preparing lithium manganate cathode materials usually use manganese source materials such as various manganese oxides or manganese salts, and these manganese oxides or manganese salts are usually made of manganese sulfate. Therefore, these manganese oxides or manganese salts are usually made of manganese sulfate. SO in manganese salt 4 2- The content is relatively high, generally 0.6% to 2%, and it is difficult to be removed. The lithium manganate product SO made from this manganese source material 4 2- The content reaches 0.8% to 2%, which seriously affects the electrochemical performance of lithium manganate cathode material

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] Embodiment 1: 2kg manganese carbonate (SO 4 2- The mass percentage is 0.96%) into the sintering furnace, the temperature is raised to 750°C at a rate of 1.5°C / min, sintered for 18 hours, the temperature is lowered to 300°C at a rate of 1.5°C / min, and cooled to room temperature with the furnace. Grinding, passing through a 200-mesh sieve to obtain the precursor of lithium manganate, the SO of the precursor 4 2- The mass percentage content is 0.1%. Mix the lithium manganate precursor and lithium carbonate according to the molar ratio of Mn:Li =2:1.05, heat up to 700°C at a speed of 3°C / min in a sintering furnace, sinter for 20 hours, and then sinter at a speed of 3°C / min Cool to room temperature, grind, sieve, the obtained lithium manganate product SO 4 2- The content is 0.09%, and the lithium-ion battery assembled with the lithium manganese oxide as the positive electrode material has a capacity retention rate of 86% at 1C rate of 1000 cycles.

Embodiment 2

[0010] Embodiment 2: 2kg chemical manganese dioxide (SO 4 2- The mass percentage is 1.23%) into the sintering furnace, heated up to 700°C at a rate of 2°C, sintered for 14 hours, cooled to 300°C at a rate of 2°C, and cooled to room temperature with the furnace. Grinding, passing through a 200-mesh sieve to obtain the precursor of lithium manganate, the SO of the precursor 4 2- The mass percentage content is 0.19%. Mix the lithium manganate precursor and lithium carbonate according to the molar ratio of Mn:Li=2:1.05, heat up to 750°C at a speed of 2°C / min in a sintering furnace, sinter for 18 hours, and then sinter at a speed of 2°C / min Cool to room temperature, grind, sieve, the obtained lithium manganate product SO 4 2- The mass percentage is 0.18%, and the lithium ion battery assembled with the lithium manganate as the positive electrode material has a capacity retention rate of 81% at 1C rate of 1000 cycles.

Embodiment 3

[0011] Embodiment 3: 2kg electrolytic manganese dioxide (SO 4 2- The mass percent content is 1.9%) into the sintering furnace, heated up to 800°C at a rate of 3°C, sintered for 12 hours, cooled to 300°C at a rate of 3°C, and cooled to room temperature with the furnace. Grinding, passing through a 200-mesh sieve to obtain the precursor of lithium manganate, the SO of the precursor 4 2- The mass percentage content is 0.18%. Mix the lithium manganate precursor and lithium carbonate according to the molar ratio of Mn:Li =2:1.05, heat up to 800°C at a speed of 1.5°C / min in a sintering furnace, sinter for 16 hours, and then sinter at a speed of 1.5°C / min Cool to room temperature, grind, sieve, the obtained lithium manganate product SO 4 2- The mass percentage is 0.17%, and the lithium ion battery assembled with the lithium manganate as the positive electrode material has a capacity retention rate of 83% at 1C rate of 1000 cycles.

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Abstract

The invention discloses a method for preparing a lithium manganate anode material with low SO4<2-> content. The method comprises the following steps of: firstly, rising the temperature of a manganese source material to be 600-900 DEG C in a speed of 1-4 DEG C / min in a sintering furnace; sintering for 3-20 hours so as to obtain a lithium manganate presoma with low SO4<2-> content in percentage; secondly, mixing the lithium manganate presoma with lithium carbonate according to a mole ratio of 2:1.05; rising the temperature to be 700-900 DEG C in a speed of 1-5 DEG C / min in the sintering furnace; sintering for 12-20 hours so as to obtain a lithium manganate product with the SO4<2-> content less than or equal to 0.2%. The lithium manganate anode material prepared by using the method is low in SO4<2-> content, the capacity retention ratio of a lithium ion battery which is prepared from the lithium manganate anode material under 1C multiplying power when being recycled for 1,000 times is greater than 80%, the first-discharge capacity is improved, and at the same time the recycling performance and the storage performance of the lithium manganate anode material of the lithium ion battery are greatly improved, so that good foundation for rapid development of the lithium manganate anode material in the lithium ion power battery industry is laid.

Description

technical field [0001] The present invention relates to a low SO 4 2- The preparation method of lithium manganate cathode material with high content. Background technique [0002] Advanced battery materials, especially cathode materials that determine the performance of lithium-ion batteries, are the key to the development of lithium-ion batteries. Lithium manganese oxide cathode material has the characteristics of abundant resources, low price, environmental friendliness, and good safety performance, and is considered to be the cathode material for lithium-ion batteries with the most development potential. However, due to problems such as manganese dissolution, crystal lattice instability and John-Teller effect, the cycle performance, high temperature performance and storage performance of lithium manganate batteries are poor, which has restricted the development of lithium manganate as a cathode material for lithium-ion batteries. major factor. Many researchers at home...

Claims

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Application Information

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IPC IPC(8): H01M4/505
CPCY02E60/10
Inventor 贺周初庄新娟彭爱国杨慧肖伟余长艳刘艳闻杰汪永斌
Owner HUNAN CHEM RES INST
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