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Asymmetric lithium iron phosphate cell using lithium titanate as main active substance of negative pole

A lithium iron phosphate battery and active material technology, applied in the direction of titanium compounds, secondary batteries, battery electrodes, etc., can solve the problem of low charge and discharge capacity, and achieve good charge and discharge performance, high specific power and high specific energy Effect

Inactive Publication Date: 2009-07-22
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the charge and discharge capacity of lithium iron phosphate at high current density is very low.

Method used

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  • Asymmetric lithium iron phosphate cell using lithium titanate as main active substance of negative pole
  • Asymmetric lithium iron phosphate cell using lithium titanate as main active substance of negative pole
  • Asymmetric lithium iron phosphate cell using lithium titanate as main active substance of negative pole

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] The preparation of lithium iron phosphate powder refers to "A polycrystalline LiFePO with olivine structure 4 Powder preparation method" (publication number: CN1410349) and "a kind of LiFePO 4 Preparation method of spherical powder "(publication number: CN1648036), lithium iron phosphate powder is prepared by the following method: first press LiFePO 4 The molar ratio of each atom in the molar ratio is 0.5:1:1 and the raw material Li is weighed 2 CO 3 , Fe(CO 2 ) 2 2H 2 O and NH 4 h 2 PO 4 , the raw materials were ball milled for 6 hours and dried, preheated at about 400°C for 8 hours in a weak reducing atmosphere, cooled to room temperature with the furnace, then taken out, ball milled for a second time for 6 hours, dried and sieved. In order to increase the tap density of the material to increase the volumetric energy density of the battery, the powder is sprayed and granulated, then put into a porcelain boat, baked at 700°C for 8 hours, and taken out after coo...

Embodiment 2

[0032] An asymmetric lithium iron phosphate battery with lithium titanate as the main active material in the negative electrode, including a positive electrode, a negative electrode, a diaphragm and an electrolyte, the main active material of the positive electrode is olivine-type lithium iron phosphate powder added with activated carbon, and the positive electrode material Also includes binder, conductive agent and dispersant, wherein, the ratio of each substance is, activated carbon: lithium iron phosphate powder: binder: conductive agent: dispersant = 10g: 70g: 10g: 10g: 0.7L, the The binder is polyvinylidene fluoride, the conductive agent is acetylene black, and the dispersant is N-methylpyrrolidone. LiFePO with spherical olivine structure 4 powder (LiFePO 4 Powder particle diameter is about 5~20 μm, and preparation method is identical with embodiment 1) 3.5g, and specific surface area is about 1500m 2 0.5g of activated carbon per gram, 0.5g of binder polyvinylidene fluo...

Embodiment 3

[0037] An asymmetric lithium iron phosphate battery whose negative electrode uses lithium titanate as the main active material, including a positive electrode, a negative electrode, a separator, and an electrolyte. The main active material of the positive electrode is olivine-type lithium iron phosphate powder, and the positive electrode material also includes viscose Bonding agent, conducting agent and dispersing agent, wherein, the proportion relationship of each material is, lithium iron phosphate powder: binding agent: conducting agent: dispersing agent=80g: 10g: 10g: 0.67L, and described binding agent is polyvinylidene fluoride ethylene, the conductive agent is acetylene black, and the dispersant is N-methylpyrrolidone. LiFePO with spherical olivine structure 4 powder (LiFePO 4 The particle size of the powder is about 5-20 μm, the preparation method is the same as in Example 1) 4.8g, the binder polyvinylidene fluoride (PVDF) 0.6g and the conductive agent acetylene black ...

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Abstract

The invention discloses an unsymmetrical lithium iron phosphate battery, the negative pole of which takes lithium titanate as the main active substance, belonging to the technical field of non water electrolysis liquid lithium ion battery or hybrid battery. The battery comprises an anode, a cathode, a diaphragm and electrolyte; wherein the main active substance of the anode is lithium iron phosphate powder, lithium iron titanate powder added with activated carbon or lithium iron phosphate powder added with carbon nanotube, the anode material also comprises caking agent, conductive agent and dispersing agent; the main active substance of the cathode is lithium titanate powder, compound copper, argentum, or lithium titanate powder or semi-conductive modified lithium titanate power, the cathode material also comprises the caking agent, the conductive agent and the dispersing agent. The caking agent is polyvinylidene fluoride, the conductive agent is acetylene black, and the dispersing agent is N-methyl pyrrolidone. The invention has good discharging property under heavy current, and can maintain high specific power and high specific energy.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion batteries or hybrid batteries of non-aqueous electrolytes, and in particular relates to an asymmetric lithium iron phosphate battery whose negative electrode uses lithium titanate as the main active material. Background technique [0002] Lithium titanate with a spinel structure is a "zero-strain material", which has excellent cycle stability and long service life, and also has good overcharge resistance and thermal stability, high safety and large specific capacity (theoretical The specific capacity is 175mAh / g, and the actual specific capacity can reach 165mAh / g). It is an excellent new battery material. [0003] Olivine-type lithium iron phosphate was first reported by the Goodenough research group in 1997 as the positive electrode material for lithium-ion batteries. This material is cheap, non-toxic, non-hygroscopic, and has good environmental compatibility, rich mineral deposits, and batt...

Claims

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Application Information

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IPC IPC(8): H01M10/38H01M4/58H01M4/38H01M4/62C01B25/45C01G23/00
CPCY02E60/12Y02E60/10Y02P70/50
Inventor 唐子龙徐睿张中太李长青贺勇
Owner TSINGHUA UNIV
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