Preparation method of lithium ion phosphate/carbon composite material for high-rate-capability lithium ion battery

A technology of lithium-ion batteries and carbon composite materials, which is applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of high-rate performance that have not been reported, and achieve good high-rate electrochemical performance, reduced energy consumption, and fine particles Effect

Inactive Publication Date: 2013-12-04
CHENGDU SCI & TECH DEV CENT CHINA ACAD OF ENG PHYSICS
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Problems solved by technology

[0010] Scholar Sinha (N.N.Sinha, N.M., J.ELECTROCHEM.SO., 2010, 157 (7) A824-A829) utilizes FePO 4 2H 2 Lithium iron phosphate was prepared by reaction of O precursor and the boiling point of tetraethylene glycol for 13 hours under normal pressure, and its high rate performance has not been reported

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  • Preparation method of lithium ion phosphate/carbon composite material for high-rate-capability lithium ion battery
  • Preparation method of lithium ion phosphate/carbon composite material for high-rate-capability lithium ion battery
  • Preparation method of lithium ion phosphate/carbon composite material for high-rate-capability lithium ion battery

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[0029] The preparation method of the lithium iron phosphate / carbon composite material for the high-rate performance lithium-ion battery of the present embodiment is characterized in that: comprising the following steps:

[0030] a. Preparation of lithium iron phosphate precursor: mix ferrous phosphate powder into lithium source, phosphorus source and conductive additive according to the ratio of Li:Fe:P=1.02-1:0.98-1:1, then add liquid phase reducing agent and Heating to the boiling point of the reducing agent solvent and reflux at normal pressure, and finally separating the reducing agent from the liquid phase system (such as reducing the reducing agent by distillation under reduced pressure) to obtain a lithium iron phosphate precursor; the reaction process does not require high-temperature calcination and inert gas protection A lithium iron phosphate positive electrode material whose surface is covered with a layer of conductive agent is prepared.

[0031] Conductive additi...

Embodiment 1

[0044] 1) Adjust the pH value to 2 with sulfuric acid and react the ferrous sulfate solution with a molar concentration of 2 mol / L and 2 mol / L ammonium dihydrogen phosphate solution in a stoichiometric ratio of 3:2, adjust the pH value to 6.0 to obtain ferrous phosphate Precipitate, quickly filtered and washed to free of SO 4 2- , put the wet filter cake in the air at room temperature to air-dry, and measure the iron and phosphorus content for later use.

[0045] 2) Add lithium source, phosphorus source, and conductive additive to the ferrous phosphate powder obtained in 1) according to the stoichiometric ratio of lithium: iron: phosphorus = 1.00:0.98:1, and then add a liquid phase reducing agent; the mass of the conductive additive is 15% of the mass of the prepared lithium iron phosphate, the molar ratio of the liquid-phase reduction solvent to the prepared lithium iron phosphate is 10:1; transfer it to a three-necked bottle, heat it with a temperature-regulating electric h...

Embodiment 2

[0052] 1) React the ferrous sulfate solution with sulfuric acid to adjust the pH value to 2 and the molar concentration of 1.5 mol / L with 1.5 mol / L ammonium dihydrogen phosphate solution according to the stoichiometric ratio of 3:2, and adjust the pH value to 5.8 to obtain phosphoric acid Ferrous precipitation, quickly filtered and washed to no SO 4 2- , put the wet filter cake in the air at room temperature to air-dry, and measure the iron and phosphorus content for later use.

[0053] 2) Add lithium source, phosphorus source and conductive additive to the ferrous phosphate powder obtained in 1) according to the stoichiometric ratio of lithium: iron: phosphorus = 1.01:0.99:1, and then add a liquid phase reducing agent. The mass of the conductive additive is 5% of the obtained lithium iron phosphate mass; the molar ratio of the liquid-phase reduction solvent to the obtained lithium iron phosphate is 8:1; transferred to a three-necked bottle, heated with a temperature-regulati...

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Abstract

The invention discloses a preparation method of a lithium ion phosphate/carbon composite material for a high-rate-capability lithium ion battery. The preparation method comprises the following steps: analyzing the iron content and the phosphorus content of a precursor ferrous phosphate powder; adding into mixed slurry of a lithium source, a ferrous phosphate precursor and a phosphorus source according to the molar ratio of Li:Fe:P=(1.02-1):(0.98-1):1, adding a proper amount of a liquid phase reducing agent and a conductive additive, performing reflux reaction at the boiling point temperature of the reducing agent, distilling under reduced pressure and recovering a reducing solvent to obtain a lithium ion phosphate precursor; and calcining under the protection of inert gas to obtain a LiFePO4/C composite anode material. Compared with other methods, the preparation method has the advantages of simple flow, short reaction time, simple process equipment, fine synthesis product particles, uniform particle size distribution, good high-rate electrochemical performance and excellent circulating stability, and besides, the discharging specific capacity is up to 100 mAh/g at 10 C,. The synthesis reaction process does not need a high-pressure container and only needs short high-temperature calcining time, so the reducing solvent is easy to recover, energy consumption is greatly reduced; the industrial popularization is facilitated.

Description

technical field [0001] The invention relates to the field of preparation of high-rate lithium-ion battery cathode materials, in particular to a method for preparing a high-rate characteristic lithium iron phosphate / carbon composite cathode based on a polyhydroxyl solvent wet heat method. Background technique [0002] In today's world, oil resources are becoming increasingly tense and environmental pollution is becoming more and more serious. People are paying more and more attention to secondary energy powered by green secondary batteries. The huge demand in the fields of national defense, aerospace, electric tools, electric vehicles, electronic information, and instrumentation has made the new generation of power-type green energy storage devices represented by lithium-ion power batteries a hot spot in the global high-tech industry. [0003] Cathode materials have always played a decisive role in the performance of lithium-ion batteries. For lithium-ion power batteries, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58
CPCY02E60/12Y02E60/10
Inventor 刘昊李绍敏刘焕明梅军
Owner CHENGDU SCI & TECH DEV CENT CHINA ACAD OF ENG PHYSICS
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