Lamina-structure lithium-contained composite metal oxide coated with carbon and use thereof

A layered structure, composite metal technology, applied in the field of materials, can solve problems such as layered compounds that have not yet been coated with carbon materials, and achieve improved surface electronic conductivity and electrical contact, low price, charge-discharge efficiency and cycle performance. improved effect

Active Publication Date: 2007-06-13
INST OF PHYSICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, so far, there have been no reports of lay

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] 0.02mol Cr(NO 3 ) 3 9H 2 O, 0.1267mol CH 3 COOLi·2H 2 O and 0.0533mol Si(OC 2 h 5 ) 4 dissolved in appropriate amount of CH 3 CH 2 OH, slowly add NH 3 ·H 2 O, adjust the pH of the solution to 9.5-10.5, let it stand still to form a gel, place it in an oven at 100° C. for 10 hours to evaporate the solvent to dryness, and obtain a precursor. After the precursor was mechanically ball milled for 4 hours, it was heated in a tube furnace at 400°C for 10 hours under Ar gas, then mechanically ball milled for 4 hours after cooling down, and then kept in a tube furnace at 900°C for 10 hours to obtain Li[Cr 0.2 Li 0.267 Si 0.533 ]O 2 . Li[Cr 0.2 Li 0.267 Si 0.533 ]O 2 Put it in a tube furnace again, let it flow into toluene gas at 600°C for 30 minutes, and then lower it to room temperature to obtain a layered lithium-containing composite metal oxide composite material 1 with a disordered carbon layer on the surface. After chemical analysis, the material is Its ca...

Embodiment 2

[0059] 0.01mol Cr 2 o 3 , 0.06335mol Li 2 CO 3 and 0.0533mol SiO 2 The precursor was obtained by mixing mechanical ball milling for 4 hours, and then kept at 900 °C under Ar gas for 10 hours to obtain Li[Cr 0.2 Li 0.267 Si 0.533 ]O 2 . With embodiment 1, in Li[Cr 0.2 Li 0.267 Si 0.533 ]O 2 The surface is covered with a carbon layer. The difference is that the carbon source gas is acetylene, the reaction temperature is 800°C, and the holding time is 8 hours. The carbon-coated Li[Cr 0.2 Li 0.267 Si 0.533 ]O 2 Composite material 2. Electrodes and test cells were prepared in the same manner as in Example 1. The coating parameters and electrochemical performance test results are listed in Table 1.

Embodiment 3

[0061]Similar to Example 1, the stoichiometric ratio of the precursor was changed, and the sol-gel method was used to obtain Li[Cr 0.2 Li 0.4 Si 0.2 ]O 2 . With embodiment 1, in Li[Cr 0.2 Li 0.267 Si 0.533 ]O 2 The surface is covered with a carbon layer. The difference is that the carbon source gas is ethylene, the reaction temperature is 1000°C, and the holding time is 24 hours. The carbon-coated Li[Cr 0.4 Li 0.2 Si 0.4 ]O 2 Composite material 3, using the same method as in Example 1 to prepare electrodes and test batteries. The coating parameters and electrochemical performance test results are listed in Table 1.

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Abstract

Being as composite material with a nucleocapsid structure, the disclosed core material is in laminated structure of composite metal oxide granules containing lithium, and carbon layer as shell covers granule. Structural features of the composite metal oxide material are that oxygen atom layer, lithium atom layer, oxygen atom layer, metal layer and oxygen atom layer are arranged alternately in sequence in direction perpendicular to c axis in crystal structure. The composite metal improves surface electron conductance and electric contact so as to raise charging and discharging specific capacity and magnification performance. Features are: high charging and discharging efficiency, improved cycle performances, low cost and no pollution, high energy density of lithium cell of using the composite material as material for positive pole, safety, and applicable to multiform occasion.

Description

technical field [0001] The invention belongs to the technical field of materials, and in particular relates to a layered structure lithium-containing composite metal oxide coated with carbon on the surface and its application in the manufacture of positive electrode materials for secondary lithium batteries with high energy density. Background technique [0002] At present, the positive electrode active materials of secondary lithium batteries mainly include LiCoO with layered structure. 2 , LiNiO 2 and LiNi x co 2-x mn x o 2 and LiMn with spinel structure 2 o 4 and LiFePO with olivine structure 4 Wait. Among them, LiMn with spinel structure 2 o 4 Capacity is 110mAh / g, suitable for high power batteries, LiFePO with olivine structure 4 The capacity is 150mAh / g, its density is low, the rate performance is poor, but the safety is better. These two types of materials are not suitable for application in high energy density secondary lithium batteries. [0003] Compou...

Claims

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Application Information

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IPC IPC(8): H01M4/58H01M4/48C01D15/00C01G1/02B22F1/02H01M4/485
CPCY02E60/10
Inventor 李泓米欣黄学杰
Owner INST OF PHYSICS - CHINESE ACAD OF SCI
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