Anode Slurry Binder Matching Surface Oxygen for Stable Coating
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Solution Overview
Problem
Existing anode active materials in secondary batteries face issues with phase stability, coating stability, and adhesion due to varying oxygen content on the surface, leading to degraded battery performance and life.
Innovation Solution
An anode slurry composition is developed with a specific ratio of zeta potential of the binder to oxygen content on the anode active material surface, using a copolymer of (meth)acrylic acid, acrylonitrile-based, and (meth)acrylamide monomers, enhancing adhesion and coating stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of oxygen on the anode active material surface is increased to improve storage capacity, then storage capacity increases, but a large activation energy is required during intercalation/deintercalation of lithium ions resulting in degradation of cycle characteristics and rate capability
Solution Approach 1:
The invention changes the surface oxygen content parameter of the anode active material to a specific range (0.5×10^-4 to 5.0×10^-4 g/m2) to optimize the balance between storage capacity and cycle characteristics. This parameter optimization reduces activation energy for lithium ion intercalation while maintaining adequate storage capacity.
Solution Approach 2:
The invention applies local quality modification by controlling the surface properties (oxygen content) of the anode active material differently from the bulk material. The surface is specifically engineered with controlled oxygen content to facilitate lithium ion intercalation, while the bulk material maintains its storage capacity properties.
2Strength
If a binder is used regardless of the amount of oxygen present on the surface of the anode active material, then adhesion is maintained, but stability of the anode slurry is degraded or poor coating occurs
Solution Approach 1:
The invention changes the zeta potential parameter of the binder to a specific range (-30 mV to -60 mV) and optimizes the ratio between binder content and surface oxygen content of the anode active material. This parameter optimization ensures both adhesion and slurry stability without poor coating.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves phase stability and coating uniformity, resulting in better rate capability, charge/discharge characteristics, and cycle characteristics of secondary batteries.
Implementation Method 1
a value obtained by dividing an absolute value of a zeta potential of the binder by an oxygen content per specific surface area of the anode active material is in a range from 0.6×10−5 mV·m2/g to 2.0×10−5 mV·m2/g
Data Source
AI summary
The present disclosure relates to an anode slurry composition for secondary batteries, comprising an anode active material; and a binder including a copolymer of (meth)acrylic acid monomer, acrylonitrile-based monomer, and (meth)acrylamide monomer, wherein a value obtained by dividing an absolute value of a zeta potential of the binder by an oxygen content per specific surface area of the anode active material is in a range from 0.6×10−5 mV·m2/g to 2.0×10−5 mV·m2/g.