Lithium titanate composite electrode material with surface coating layer

A surface coating, composite electrode technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve problems affecting battery capacity and cyclability, achieve good application prospects, avoid inflation, and change surface physical and chemical properties Effect

Inactive Publication Date: 2010-06-30
SUZHOU PHYLION BATTERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The lithium intercalation potential of lithium titanate is high, above 1V, and the SEI film will not be formed under normal circumstances, but in the actual use process, it is easy to generate overpotential, which makes the potential of the negative electrode of the lithium battery drop below 1V, resulting in lithium titanate and The electrolyte reacts and decomposes to produce gas with no place to release, causing gas swelling, which affects the capacity and cycle performance of the battery

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] In order to illustrate the electrochemical performance of the lithium titanate composite electrode material with a surface coating layer of the present invention, an experimental battery is used as an example. The above-mentioned method 4 is used for the coating treatment of the negative electrode active material, and the lithium titanate powder is added to the 2.0mol / L ammonium bicarbonate solution and mixed evenly, and 0.2mol / L sulfuric acid is added dropwise to the solution at a rate of 2-3ml / min. Aluminum ammonium solution, the pH of the reaction system is controlled to be 8.5-10.0, the precursor aluminum ammonium carbonate is precipitated and coated on the surface of lithium titanate particles, and the surface is coated with Al by heat treatment after supercritical drying. 2 o 3 Lithium titanate composite material. Coat the surface with Al 2 o 3 Lithium titanate composite electrode material (the average thickness of the coating layer is 2nm, the average particle...

Embodiment 2

[0021] Using method 3 above, the titanium alkoxide [Ti(OR) 4 ]After spraying and cooling with inert gas, submicron droplets are formed, which form capsules with fluidized lithium titanate particles, react with water vapor, and form surface-coated TiO at 100-500°C 2 Lithium titanate composite material. Coat the surface with TiO 2 Lithium titanate composite electrode material (the average thickness of the coating layer is 10nm, and the average particle size of lithium titanate particles is 5μm), acetylene black and conductive graphite, and the binder polyvinylidene fluoride PVDF in a mass ratio of 90:4:6 (The sum of acetylene black and conductive graphite, accounting for 4% of the total proportion) is mixed evenly, coated on the copper foil, and cut into pole pieces after drying. The electrolyte LiPF 6 Dissolved in a mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) with a volume ratio of 1:1 to form an electrolyte, the concentration of the electrolyte is 1 m...

Embodiment 3

[0023] Using the above method 1, alcohols are used as solvents, ethyl silicate undergoes hydrolysis reaction under acidic conditions to form a silicon dioxide precursor solution, the surface pretreated lithium titanate is added to the solution and stirred, and the temperature is raised to volatilize the solvent. Sintered to obtain surface-coated SiO 2 Lithium titanate composite material. Coat the surface with SiO 2 Lithium titanate composite electrode material (the average thickness of the coating layer is 5nm, the average particle size of lithium titanate particles is 5μm), acetylene black and conductive graphite, binder polyvinylidene fluoride PVDF in a mass ratio of 90:4:6 (The sum of acetylene black and conductive graphite, accounting for 4% of the total proportion) is mixed evenly, coated on the copper foil, and cut into pole pieces after drying. The electrolyte LiPF 6 Dissolved in a mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) with a volume ratio...

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Abstract

The invention relates to a battery electrode material, in particular to a lithium titanate composite electrode material with surface coating layer; in the lithium titanate composite electrode material with surface coating layer, the electrode material is composed of lithium titanate particles and a coating layer coated with the surface of the lithium titanate particles; the particle size of the lithium titanate particles is 100nm-95mum, the average thickness of the surface coating layer is 0.2nm-5m, and the particle diameter of the composite electrode material is 0.1-100mum; the material of the surface coating layer is one or mixture of more than one kind of insulation oxide, insulation composite oxide, aluminium phosphate, magnesium phosphate, lithium fluoride, lithium phosphate or LiMPO4, wherein M is magnesium, ferrum, cobalt, nickel, chromium, titanium or vanadium; in the invention, by carrying out surface coating treatment to the surfaces of the existing lithium titanate particles, a layer of protective film is formed on the surface, so as to change the physical and chemical characteristics of the surface of the lithium titanate active material, the surface can not be reacted with electrolyte even if under overpotential condition, so as to avoid ballooning and ensure the capacity and the circularity of the battery not to be reduced.

Description

technical field [0001] The invention relates to a battery electrode material, in particular to a lithium titanate composite electrode material with a surface coating layer. Background technique [0002] In recent years, spinel lithium titanate Li 4 Ti 5 o 12 As an electrode material for a new type of energy storage battery, more and more attention has been paid to it. This is because the crystal structure of spinel lithium titanate can maintain a high degree of stability during the lithium ion intercalation ~ deintercalation process, and the spinel structure is always present before and after lithium ion intercalation. , and the lattice constant changes very little, and the volume change is very small, so lithium titanate is called "zero strain" electrode material. This can avoid the structural damage caused by the back and forth expansion and contraction of the electrode material during the charge-discharge cycle, thereby improving the cycle performance and service life ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/131
CPCY02E60/122Y02E60/12Y02E60/10
Inventor 吴晓东
Owner SUZHOU PHYLION BATTERY
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