Core-Shell Anode Coating for Uniform Slurry Dispersion
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Solution Overview
Problem
Lithium secondary batteries face challenges in anode production due to the hydrophobic nature of carbon-based materials, leading to low miscibility with hydrophilic solvents, poor dispersion uniformity, and increased productivity costs, as well as initial irreversible reactions and capacity reduction due to the formation of a solid electrolyte interface (SEI) layer.
Innovation Solution
A method involving a core-shell structure where a crystalline carbon-based material is coated with a composite layer of low crystalline or amorphous carbon and silicon oxide, enabling intercalation and deintercalation of ions, is developed. This involves mixing a precursor with silicon oxide, purifying it, and then applying it to the crystalline carbon-based core, followed by baking to create a uniform composite coating layer that improves hydrophilicity and electrolyte impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If carbon-based material is used as anode active material, then high energy density and voltage are achieved, but hydrophobicity causes low miscibility with hydrophilic solvent and poor dispersion uniformity
Solution Approach 1:
The patent applies composite materials by combining carbon-based anode active material with hydrophilic materials (such as metal oxides or hydrophilic polymers) to create a composite structure. This composite approach allows the material to maintain the high energy density of carbon while introducing hydrophilic properties that improve miscibility with hydrophilic solvents and achieve uniform dispersion in the slurry.
2Use of energy by moving object
If carbon-based material is used as anode active material, then high energy density is achieved, but hydrophobicity complicates electrolyte impregnation and decreases productivity
Solution Approach 1:
By creating composite materials with hydrophilic components, the anode structure facilitates faster and more uniform electrolyte impregnation. The hydrophilic portions of the composite material attract and retain electrolyte more effectively, reducing impregnation time and improving overall productivity while preserving the high energy density characteristics of the carbon-based material.
3Reliability
If SEI layer is formed on carbon-based anode, then initial charge/discharge process occurs, but electrolyte is consumed and battery capacity is reduced
Solution Approach 1:
The patent modifies the surface properties and composition of the anode material through composite formation, changing parameters such as surface energy, porosity, and chemical composition. These parameter changes enable the formation of a more stable and thinner SEI layer during initial activation, reducing electrolyte consumption and minimizing capacity loss while still achieving proper electrode activation.
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
The method enhances the uniformity of the anode active material, reduces impregnation time, maintains electrical conductivity, and inhibits lithium dendrite growth, resulting in improved battery productivity and capacity retention over multiple charge/discharge cycles.
Implementation Method 1
silicon oxide enabling intercalation and deintercalation of ions
Implementation Method 2
baking the core-shell precursor to carbonize the raw material of the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon into the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon
Data Source
AI summary
Disclosed is a method for preparing an anode active material comprising a core composed of a crystalline carbon-based material, and a composite coating layer comprising (a) mixing a precursor for a raw material of one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon with silicon oxide enabling intercalation and deintercalation of ions, followed by purification, to prepare a mixture for coating, (b) mixing the mixture for coating with a crystalline carbon-based material to prepare a core-shell precursor comprising the raw material mixture for coating applied to the core composed of the crystalline carbon-based material, and (c) baking the core-shell precursor to carbonize the raw material of the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon into the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon.