Cathode active material, cathode, and nonaqueous electrolyte secondary battery

A positive electrode active material and non-aqueous electrolyte technology, which is applied in the field of positive electrode active materials and non-aqueous electrolyte secondary batteries, can solve the problems of reducing high power characteristics, reducing the amount of positive electrode active materials, and reducing battery capacity.

Active Publication Date: 2009-06-03
MURATA MFG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This causes problems of suppressing the conductivity of the electrode, lowering high-power characteristics, and lowering productivity in the coating step due to an increase in the amount of solvent in the positive electrode mixture
Also, the amount of positive electrode active material decreases, which leads to a decrease in battery capacity

Method used

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  • Cathode active material, cathode, and nonaqueous electrolyte secondary battery
  • Cathode active material, cathode, and nonaqueous electrolyte secondary battery
  • Cathode active material, cathode, and nonaqueous electrolyte secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0096] In Example 1, primary particles or secondary particles prepared from primary particles were used as the positive electrode active material. When the secondary particles were used, the ratio of the pore size of the secondary particles to the average particle size of the primary particles was changed to produce a secondary battery, and then the battery characteristics of the secondary battery were examined.

[0097] For secondary particles used as positive electrode active materials, lithium iron phosphate (LiFePO 4 ) (with an average particle diameter of 50 nm, 100 nm, 150 nm, 200 nm, 300 nm, and 500 nm) are produced as primary particles. In the examples, the term "average particle diameter of primary particles" refers to carbon-coated lithium iron phosphate (LiFePO 4) The average particle size of the total diameter. The secondary particles are granulated by spray drying and the pore size of the secondary particles is controlled by adjusting the concentration of the so...

Embodiment 2

[0196] In Example 2, primary particles or secondary particles prepared from primary particles were used as the positive electrode active material. The thickness of the positive electrode active material layer was varied at a constant bulk density to produce a secondary battery, and then the DC resistance of the secondary battery was detected.

[0197] In this regard, the average particle diameter of the primary particles and the pore diameter of the secondary particles used in Example 2 were examined in the same manner as described in Example 1.

[0198]

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Abstract

The present application provides a nonaqueous electrolyte secondary battery which includes a cathode having a cathode active material layer, an anode, and a nonaqueous electrolyte, wherein the cathode active material layer includes secondary particles of a lithium phosphate compound having olivine structure, an average particle diameter A of primary particles constituting the secondary particles is 50 nm or more and 500 nm or less, and a ratio B / A of a pore diameter B of the secondary particles to the average particle diameter A of the primary particles is 0.10 or more and 0.90 or less, preferred 0.10 or more and 0.75 or less.

Description

[0001] Cross References to Related Applications [0002] The present application contains subject matter related to Japanese Patent Application JP 2007-311700 filed in the Japan Patent Office on Nov. 30, 2007, the entire content of which is hereby incorporated by reference. technical field [0003] The present invention relates to a positive electrode active material and a nonaqueous electrolyte secondary battery, and more particularly, to a positive electrode active material, a positive electrode, and a nonaqueous electrolyte secondary battery which are excellent in high capacity and high power characteristics. Background technique [0004] Recently, many portable electronic devices, such as camera-integrated video tape recorders (VTRs), mobile phones, or laptop computers, have appeared, and reductions in their size and weight have been considered. Research and development of batteries, especially secondary batteries to be used as portable power sources of such electronic d...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/36H01M4/02H01M4/58H01M4/136H01M4/36H01M4/62H01M10/052
CPCH01M4/5825Y02E60/122H01M2004/028Y02T10/7011H01M10/052G11B5/596H01M2004/021H01M4/366H01M4/364H01M4/136Y02E60/10H01M4/58H01M4/02H01M10/05Y02P70/50Y02T10/70
Inventor 石井武彦
Owner MURATA MFG CO LTD
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