Rare-earth-doped lithium manganese silicate positive electrode material and microwave-assisted preparation method thereof

A technology of lithium manganese silicate and positive electrode materials, applied in battery electrodes, electrical components, electrochemical generators, etc., can solve problems such as low reaction efficiency, uneven distribution of doping components, and poor wave absorption

Inactive Publication Date: 2018-05-18
UNIV OF JINAN
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Our previous study found that the microwave method can effectively improve the Li 2 MnSiO 4 The electrochemical performance of the material, but the iron, magnesium and other metal elements reported in the literature have problems such as low reaction efficiency and uneven distribution of doping components during the synthesis process due to their poor absorbing properties.

Method used

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  • Rare-earth-doped lithium manganese silicate positive electrode material and microwave-assisted preparation method thereof
  • Rare-earth-doped lithium manganese silicate positive electrode material and microwave-assisted preparation method thereof
  • Rare-earth-doped lithium manganese silicate positive electrode material and microwave-assisted preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Lithium acetate, manganese acetate, methyl orthosilicate, a certain amount of citric acid (accounting for 25% of the total mass) and rare earth compound lanthanum nitrate according to the ratio of Li: Mn: Si: La material amount is 2.02:0.99:1 : 0.01 was added to an appropriate amount of dispersant (80ml distilled water, 20ml ethanol) to mix and disperse, then 12ml ammonia water with a mass fraction of 20% was added dropwise as a catalyst, heated and stirred at 80°C for 8h, and then evaporated to dryness in a water bath and solvent ground to obtain lanthanum doped Lithium manganese silicate material precursor. Afterwards, the precursor was transferred to a microwave field, and the temperature was raised to 650 °C at a heating rate of 20 °C / min. Under the protection of a 10% hydrogen / 90% argon mixed atmosphere, microwave heat treatment was performed for 150 min, and then rapidly cooled to room temperature to obtain Product Li 2 mn 0.99 La 0.01 SiO 4 / C material. Depe...

Embodiment 2

[0035] Lithium nitrate, manganese dioxide, silicon dioxide, a certain amount of phenolic resin (accounting for 30% of the total mass), and rare earth compounds neodymium nitrate and lanthanum nitrate according to the ratio of Li: Mn: Si: Nd: La to 2.02 :0.94:1:0.03:0.03 After mixing evenly, add it to a ball mill jar, mill it in a planetary ball mill at a speed of 200r / min for 2 hours, make it fully mixed, and dry to obtain a precursor of neodymium-lanthanum doped manganese lithium silicate material . Afterwards, the precursor was transferred to a microwave field, and the temperature was raised to 670 °C at a heating rate of 15 °C / min. Under the protection of an argon atmosphere, microwave heat treatment was performed for 150 min, and the product Li was obtained after cooling down with the furnace. 2 mn 0.94 Nd 0.03 La 0.03 SiO 4 / C material.

Embodiment 3

[0037] Lithium acetate, manganese acetate, ethyl orthosilicate, a certain amount of ascorbic acid (accounting for 35% of the total mass) and rare earth compound cerium nitrate according to the ratio of Li:Mn:Si:Ce is 2.03:0.97:1: Add 0.03 to an appropriate amount of dispersant (100ml of water, 25ml of ethanol) to mix and disperse, then add 10ml of ammonia water with a mass fraction of 25% dropwise as a catalyst, heat and stir at 70°C for 10h, then evaporate to dryness in a water bath and grind the solvent to obtain cerium-doped silicon Manganese oxide lithium material precursor. Afterwards, the precursor was transferred to a microwave field, and the temperature was raised to 680 °C at a heating rate of 20 °C / min. Under the protection of a mixed atmosphere of 5% hydrogen / 95% argon, microwave heat treatment was performed for 100 min, and the cooling rate was 10 °C / min. Slowly down to room temperature, the product Li 2 mn 0.97 Ce 0.03 SiO 4 / C material, using the product as t...

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Abstract

The invention relates to a rare-earth-doped lithium manganese silicate positive electrode material and a microwave-assisted preparation method thereof. The preparation method mainly comprises the following steps that firstly, a certain quantity of lithium sources, manganese sources, silicon source compounds, carbon source additives and rare earth compounds serve as raw materials to prepare a rare-earth-doped lithium manganese silicate material precursor; secondly, the precursor is placed in a microwave field for microwave sintering under a protective gas atmosphere to obtain the rare-earth-doped lithium manganese silicate positive electrode material. According to the preparation method, the stability of the material is improved through the octahedral site preference energy characteristic of rare earth elements; the excellent wave absorbing property of the rare earth elements and microwave-assisted thermal treatment are combined, so that the wave absorbing property of the material is remarkably improved, then reaction frequency is increased when microwaves are propagated in a base material, a reaction can be conducted more sufficiently, the purity of the product is improved, and theelectrochemical performance of the material is further optimized; the synthesis period is shortened, and the production efficiency is improved.

Description

technical field [0001] The invention relates to a rare earth-doped lithium manganese silicate cathode material and a microwave-assisted preparation method thereof. Background technique [0002] As a kind of electrode material for lithium-ion batteries, polyanionic positive electrode materials have attracted extensive attention and research due to their good structural stability, safety performance and high theoretical capacity. At present, olivine and NASICON two structural types of polyanionic cathode materials. Among them Li 2 MnSiO 4 As a member of polyanionic cathode materials, the material is considered to be a promising candidate material for lithium-ion batteries due to its high theoretical capacity, low raw material cost, and environmental protection. [0003] In 2006, R. Dominko and his research group used the improved sol-gel method to synthesize Li for the first time using citric acid as a complexing agent. 2 MnSiO 4 Cathode material. Currently Li 2 MnSiO ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/58H01M4/583H01M10/0525
CPCH01M4/366H01M4/5825H01M4/583H01M10/0525Y02E60/10
Inventor 马东玮冯季军常彩云
Owner UNIV OF JINAN
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