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US 10,476,078 B2Granted
Positive electrode for secondary battery, method of preparing the same, and lithium secondary battery including the positive electrode
AssigneeLG Chem, Ltd.
InventorsYoung Geun Choi, Kang Kun Kim, Song Taek Oh, Joo Young Choi, Ji Hye Yang
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Abstract
The present invention relates to a positive electrode for a secondary battery in which a maximum diameter of internal pores is controlled to be less than 1 μm, a method of preparing the same, and a secondary battery including the positive electrode.
Claims16
A positive electrode for a secondary battery, the positive electrode comprising:
- a positive electrode collector;
- and
- a positive electrode material mixture layer coated on at least one side of the positive electrode collector,
- wherein the positive electrode material mixture layer comprises a positive electrode active material, a conductive agent, a binder, and bimodal pores composed of first pores and second pores which have different average diameters, and
- the conductive agent and the positive electrode active material are included at a volume ratio (K1) of 0.08:1 to 0.32:1,
- wherein a volume ratio of the conductive agent to the total pores is in a range of 0.1:1 to 0.33:1,
- a porosity is in a range of 30 vol % to 45 vol %,
- maximum diameters of the first pores and the second pores are less than 1 μm, and
- an average diameter ratio (k) of the first pores to the second pores is in a range of 0.13:1 to 0.27:1.
6 more elements
A method of preparing a positive electrode for a secondary battery, the method comprising:
- preparing a positive electrode active material slurry having a solid content of 60 wt % to 90 wt % by mixing a conductive agent with a positive electrode active material at a volume ratio of 0.08:1 to 0.32:1;
- preparing a positive electrode including a positive electrode material mixture layer having a porosity of 55 vol % to 65 vol % by coating a positive electrode collector with the positive electrode active material slurry and drying the coated positive electrode collector;
- performing primary rolling of the positive electrode to prepare a positive electrode including a positive electrode material mixture layer having a porosity of 53 vol % to 57 vol %;
- performing secondary rolling of the positive electrode prepared after the primary rolling to prepare a positive electrode including a positive electrode material mixture layer having a porosity of 30 vol % to 45 vol %;
- and
- performing tertiary rolling of the positive electrode prepared after the secondary rolling to prepare a positive electrode including a positive electrode material mixture layer having a porosity of 30 vol % to 45 vol %.
3 more elements
Dependencies are inferred from the claim text.