Prepn process of oxygen place doped lithium ferric phosphate powder

A lithium iron phosphate, doping-type technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve problems such as ineffective effects, and achieve the effects of improving the basic capacity of the matrix, wide application prospects, and wide sources

Inactive Publication Date: 2007-08-22
TSINGHUA UNIV
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Problems solved by technology

[0004] In other cathode materials, such as spinel lithium manganese oxide LiMn 2 o 4 , usually doping with low-valent metal ions to replace the manganese site can improve the tetravalent manganese Mn 4+ The proportion in the compound, so as to stabilize the crystal structure and limit the occurrence of the Jahn-Teller effect, is a relatively effective method in improving the cycle performance at room temperature, but under high temperature (>55°C) operating conditions, the effect of this method is less not obvious

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  • Prepn process of oxygen place doped lithium ferric phosphate powder
  • Prepn process of oxygen place doped lithium ferric phosphate powder
  • Prepn process of oxygen place doped lithium ferric phosphate powder

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preparation example Construction

[0028] The specific method of preparing the oxygen-doped lithium iron phosphate powder is as follows:

[0029] 1) One-time mixing method of adulterants and parent raw materials

[0030] According to the lithium salt, ferrous salt and phosphate, mix the parent material according to the molar ratio of Li:Fe:P=1:1:1, and then mix the parent material once by the molar ratio of the parent body:dopant=1:0.001~2 material, and then add at least one of deionized water, industrial alcohol and absolute ethanol as a mixed medium to mix, mix and mill for 6 to 12 hours, and dry at 40 to 70°C; after drying, the powder is dried in nitrogen, argon Gas, at least one of nitrogen and hydrogen mixed gas in an inert atmosphere or a reducing atmosphere, heated at 400-550 ° C, and kept for 2-10 hours for pre-calcination; the matrix pre-calcined material was ball-milled for 6-12 hours, at 40-70 ℃, and then in an inert atmosphere or a reducing atmosphere of at least one of nitrogen, argon, and nitrogen-...

Embodiment 1

[0045] Mix 0.05 mol of lithium carbonate, 0.1 mol of ferrous oxalate and 0.1 mol of ammonium dihydrogen phosphate, add it to a polyester tank, add 25ml of absolute alcohol, seal it and mix it on a planetary ball mill for 10 hours, under 0.3 liters / minute of nitrogen Under the atmosphere, raise the temperature up to 400°C at a rate of 5°C / min, keep at this temperature for 8 hours, and cool down to room temperature with the furnace, take out 0.1 mole of precursor pre-fired material, add 0.04 mole of thiourea to the polyester tank, and add an appropriate amount of alcohol , ball milled for 6 hours after sealing, and then raised to 700°C at a rate of 4°C / min under a nitrogen atmosphere of 0.3 liters / min, kept at this temperature for 8 hours, and cooled to room temperature with the furnace. The resulting cathode material is LiFePS 0.4 o 3.6 , denoted as sample A. A in Figure 1 is the obtained LiFePO 4 The XRD pattern of the dopant did not change the LiFePO 4 The crystal structu...

Embodiment 2

[0048] Mix 0.05 lithium carbonate with 0.1 mole of ferrous oxalate, 0.1 mole of ammonium dihydrogen phosphate and 0.062 mole of elemental sublimed sulfur, add it to a polyester tank, add 30ml of absolute alcohol, seal it and mix it on a planetary ball mill for 6 hours. Under the nitrogen atmosphere of l / min, raise the temperature to 430°C at a rate of 5°C / min, keep at this temperature for 7.5 hours, cool down to room temperature with the furnace, take out 0.1 mole of the precursor pre-fired material and add it to the polyester tank, add an appropriate amount Alcohol, sealed and ball milled for 10 hours, then in a nitrogen-hydrogen mixed atmosphere of 0.3 liters / min (nitrogen: hydrogen = 9:1, volume ratio), the temperature rises to 720°C at a rate of 4°C / min, and is kept at this temperature After 7 hours, cool down to room temperature with the furnace. The resulting cathode material is LiFePS 0.6 2O 3.38 , denoted as sample B. B in Figure 1 is the obtained LiFePO 4 The XRD ...

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Abstract

The present invention belongs to the field of electrochemical power source material preparing technology, and is especially preparation process of oxygen place doped lithium ferric phosphate powder. The oxygen place doped lithium ferric phosphate as positive pole material in lithium ion cell has the molecular expression LiFeP(MxO4-x), and is prepared through mixing the dopant and the mother body material and sintering the mixture, or through solid phase reaction of the dopant and the mother body material. The preparation process has effective doping in the oxygen place of mother body material and the prepared material can raise the capacity and the circular discharge performance of the cell effectively and thus can find its wide application as positive pole material in secondary lithium ion cell and power cell.

Description

technical field [0001] The invention belongs to the technical field of preparation of electrochemical power source materials. In particular, it relates to a preparation method of an oxygen-doped lithium iron phosphate powder used as a common secondary lithium ion battery or a modified lithium ion battery positive electrode material for power energy. technical background [0002] Lithium-ion battery is a new type of green high-energy rechargeable battery that appeared in the early 1990s. It has many advantages such as high voltage, high energy density, good cycle performance, small self-discharge, no memory effect, and wide operating temperature range. It is widely used in mobile Telephones, notebook computers, portable electric tools, electronic instruments, weapons and equipment, etc. also have good application prospects in electric vehicles, and have become the focus of research and development by countries all over the world. The positive electrode material is an importa...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B25/45H01M4/58
CPCY02E60/12Y02E60/10
Inventor 张中太罗绍华唐子龙卢俊彪闫俊萍
Owner TSINGHUA UNIV
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