Preparation method for one-step synthesis of high-rate-performance carbon-coated lithium iron phosphate cathode material by in-situ hydrothermal carbonization

A carbon-coated lithium iron phosphate, in-situ hydrothermal technology, applied in battery electrodes, electrical components, circuits, etc., can solve the problem of poor consistency and stability of electrochemical performance, hindering the development of lithium iron phosphate power batteries, and long calcination time. and other problems, to avoid side reactions, suitable for large-scale industrial production, and the process control parameters are mild and easy to control.

Inactive Publication Date: 2012-07-11
SICHUAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current price of lithium iron phosphate is about twice that of lithium manganese oxide cathode material, which greatly hinders the development of lithium iron phosphate power batteries. However, the products prepared by traditional high-temperature solid-phase method have serious agglomeration and wide particle size distribution. The consistency and stability are poor, the calcination time is long, the temperature is high, a large amount of carbon dioxide and other gases are generated in the middle process, and multiple ball milling is required, the energy consumption is high, the synthesis process needs to use protective gas, the cost is high, and the yield of large-scale production is low.

Method used

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  • Preparation method for one-step synthesis of high-rate-performance carbon-coated lithium iron phosphate cathode material by in-situ hydrothermal carbonization
  • Preparation method for one-step synthesis of high-rate-performance carbon-coated lithium iron phosphate cathode material by in-situ hydrothermal carbonization
  • Preparation method for one-step synthesis of high-rate-performance carbon-coated lithium iron phosphate cathode material by in-situ hydrothermal carbonization

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Prepare lithium hydroxide solution (1.5 mol / L) and ferrous sulfate solution (0.5 mol / L); under stirring conditions, mix lithium hydroxide, ferrous sulfate, and phosphoric acid solution evenly, add 1.5 g of glucose, and control the pH of the solution to 6-7, the suspension was subjected to ultrasonication for 30 minutes, transferred to a magnetically stirred hydrothermal kettle, and an inert gas (nitrogen or argon) was introduced into the reactor, the hydrothermal kettle was sealed, and hydrothermal reaction was carried out at 180°C for 6 Hours, after the reaction, naturally cooled to room temperature, the slurry was separated from solid and liquid, washed three times with water and ethanol solution, and dried in a vacuum oven at 100°C for 4 hours to remove free water to obtain carbon-coated lithium iron phosphate Precursor powder material. The carbon-coated lithium iron phosphate precursor powder material is placed in a tube furnace, under the protection of an inert gas...

Embodiment 2

[0052] Prepare lithium hydroxide solution (2mol / L) and ferrous sulfate solution (1mol / L); under stirring conditions, mix lithium hydroxide, ferrous sulfate, and phosphoric acid solution evenly, add 2.5g of glucose, and control the pH of the solution to 6~ 7. Ultrasound the suspension for 30 minutes, transfer it to a magnetically stirred hydrothermal kettle, and pass an inert gas (nitrogen or argon) into the reactor, seal the hydrothermal kettle, and conduct a hydrothermal reaction at 160°C for 10 hours. After the reaction, it was naturally cooled to room temperature, the slurry was separated from solid and liquid, washed three times with water and ethanol solution, and then dried in a vacuum oven at 120°C for 2 hours to remove free water and obtain a carbon-coated lithium iron phosphate precursor powder material. The carbon-coated lithium iron phosphate precursor powder material is placed in a tube furnace, under the protection of an inert gas, heat-treated at a high temperatu...

Embodiment 3

[0055] Prepare lithium hydroxide solution (3mol / L) and ferrous sulfate solution (1mol / L); under stirring conditions, mix lithium hydroxide, ferrous sulfate, and phosphoric acid solution evenly, add 4g of glucose, and control the pH of the solution to 6-7 , the suspension was subjected to ultrasonication for 30 minutes, transferred to a magnetically stirred hydrothermal kettle, and an inert gas (nitrogen or argon) was passed into the reactor, and the hydrothermal kettle was sealed, and hydrothermal reaction was performed at 220 ° C for 3 hours. After the end, cool down to room temperature naturally, separate the slurry from solid and liquid, wash with water and ethanol solution three times, and then dry it in a vacuum oven at 80°C for 6 hours to remove free water and obtain carbon-coated lithium iron phosphate precursor powder Material. The carbon-coated lithium iron phosphate precursor powder material was placed in a tube furnace, and under the protection of an inert gas, it w...

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Abstract

The invention discloses a low-cost preparing process for one-step synthesis of carbon-coated lithium iron phosphate cathode material with excellent high-rate-performance by in-situ hydrothermal carbonization, and provides a preparation method for solving the defects that the traditional carbon-coated lithium iron phosphate preparing process is complicated, carbon coating is nonuniform and the like. The preparation method of carbon-coated lithium iron phosphate with excellent high-rate-performance comprises the step of: uniformly mixing lithium hydroxide solution, ferrous salt solution, phosphoric acid solution and a carbon source under the protection of inert gas, controlling pH value during reaction process, and after reaction is finished, carrying out solid-liquid separation, drying and high-temperature heat treatment to obtain the high-rate-performance carbon-coated lithium iron phosphate cathode material. According to the invention, lithium iron phosphate has the characteristics of uniform particle size distribution and carbon coating thickness, excellent high-rate-performance, good circulation stability and the like.

Description

technical field [0001] The invention designs a method for preparing carbon-coated lithium iron phosphate with excellent high-rate performance, and belongs to the field of lithium battery materials. Background technique [0002] Lithium-ion battery is a new generation of green high-energy rechargeable battery, which has the advantages of high voltage, small size, light weight, high specific energy, no memory, environment-friendly, small self-discharge, long life, and high safety. In recent years, there has been an upsurge in the research and development of high-performance lithium-ion batteries all over the world. In 1997, Goodenough and Padhi [1] Researched the synthesis and electrochemical performance of lithium transition metal phosphate-based cathode materials, and was the first to discover LiFePO 4 It has reversible lithium storage performance, the discharge platform voltage is about 3.5V, and the actual capacity is close to 130mAh / g (theoretical capacity is 170mAh / g)....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/58H01M4/1397
CPCY02E60/122Y02E60/10
Inventor 陈云贵徐程浩
Owner SICHUAN UNIV
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