A kind of preparation method of potassium manganese doped lithium iron phosphate composite cathode material with high conductivity

A composite positive electrode material, lithium iron phosphate technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of poor conductivity of lithium ions, low purity, easy growth of product grains, etc., to achieve good conductivity and cycle stability, improve ion diffusion performance, and inhibit agglomeration

Inactive Publication Date: 2016-08-03
江西锐格新能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The high-temperature solid-phase method is to roast lithium source compounds, iron source compounds, and phosphorus source compounds under the protection of an inert atmosphere to synthesize lithium iron phosphate; the advantage of the high-temperature solid-phase method is that the process is simple and easy to achieve industrialization, but the reactants are usually mixed unevenly. The product particles and grains are easy to grow, the purity is not high, the primary particle is too large, the migration path of lithium ions is too long, and the conductivity of lithium ions is poor, so the electrochemical performance is not good

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] The chemical formula of the multi-element doped lithium iron phosphate is Li 0.85 K 0.15 Fe 0.7 mn 0.3 PO 4 .

[0019] Lithium hydroxide, ferrous oxalate, ammonium dihydrogen phosphate, manganese acetate and potassium carbonate are weighed according to the molar weights of Li, K, Fe, Mn and P in the above chemical formula, and mixed mechanically to form mixture one; Agents are mixed at a weight ratio of 1:0.2 and dissolved in a solvent to form a mixture 2, wherein the complexing agent is glucose, and the solvent is ethylene glycol; the mixture 2 is ball milled in a planetary ball mill at a speed of 400r / min for 30h; Put the ball-milled mixture 2 in a vacuum dryer and dry at a temperature of 100°C for 8 hours to obtain a powder, and pulverize the obtained powder with a crushing equipment; place the pulverized powder in a reducing atmosphere furnace and pre-heat at a temperature of 300°C. After 20 hours of treatment, the nano-lithium iron phosphate precursor was obta...

Embodiment 2

[0022] The chemical formula of the multi-element doped lithium iron phosphate is Li 0.7 K 0.3 Fe 0.65 mn 0.35 PO 4 .

[0023] Lithium hydroxide, ferrous oxalate, ammonium dihydrogen phosphate, manganese acetate and potassium carbonate are weighed according to the molar weights of Li, K, Fe, Mn and P in the above chemical formula, and mixed mechanically to form mixture one; Agents are mixed in a weight ratio of 1:0.5 and dissolved in a solvent to form a mixture 2, wherein the complexing agent is glucose, and the solvent is ethylene glycol; the mixture 2 is ball milled in a planetary ball mill at a speed of 500r / min for 20h; Put the ball-milled mixture 2 in a vacuum dryer and dry at a temperature of 150°C for 12 hours to obtain a powder, and pulverize the obtained powder with a crushing equipment; place the pulverized powder in a reducing atmosphere furnace at a temperature of 700°C to pre- Treat for 5 hours to obtain the nano-lithium iron phosphate precursor.

[0024] Mix...

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Abstract

The invention relates to a preparation method of a potassium and manganese doped lithium iron phosphate composite anode material with high conductivity. The chemical formula of the multielement doped lithium iron phosphate composite anode material is Li(1-x)KxFe(1-y)MnyPO4, wherein x=0.15-0.3 and y=0.3-0.35. the preparation method comprises following steps: (1) a nano lithium iron phosphate precursor is prepared; and (2) acetylene black and polyethylene glycol are mixed, and the mixture is dispersed in ethanol by ultrasonic dispersion so as to obtain a conductive carbon dispersion liquid; the nano lithium iron phosphate precursor and the conductive carbon dispersion liquid are mixed, and the mixed solution is subjected to ball milling by a planetary ball mill; and the substances obtained after ball milling are dried, and are subjected to sintering in the presence of a reducing protective atmosphere so as to obtain the products. The potassium and manganese doped lithium iron phosphate composite anode material is used for lithium ion batteries; lithium iron phosphate is modified by doping of K and Mn, so that ion diffusivity is increased, generation of agglomeration is inhibited, and a conductive carbon-carbon network on the surface of lithium iron phosphate is formed.

Description

Technical field [0001] The invention relates to a preparation method of a high-conductivity potassium-manganese-doped lithium iron phosphate composite positive electrode material. Background technique [0002] With the rapid development of the battery industry, in order to solve many problems such as battery life, energy density, self-discharge or quality, various types of batteries have emerged. At present, due to the advantages of high energy density, long service life, light weight, and small self-discharge, lithium batteries have become the preferred power source for portable devices such as communication equipment and notebook computers, and have also begun to be applied to electric vehicles, national defense, etc. in large equipment. [0003] Lithium iron phosphate material is a cathode material for power lithium-ion batteries that has emerged in recent years and has been applied in large-scale industrialization. It has the property of intercalating and deintercalati...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/58H01M4/62
CPCY02E60/10
Inventor 王金锋周洋洋
Owner 江西锐格新能源科技有限公司
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