Anode Active Material Coating for Battery Electrolyte Impregnation
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Solution Overview
Problem
Lithium secondary batteries face challenges in anode fabrication due to the hydrophobic nature of carbon-based anode active materials, leading to low miscibility with hydrophilic solvents and complex electrolyte impregnation, as well as issues with the formation and stability of the solid electrolyte interface (SEI) layer, which affect battery capacity and productivity.
Innovation Solution
A method involving a core-shell structure where a crystalline carbon-based material is coated with a composite layer comprising low crystalline or amorphous carbon and a hydrophilic material, achieved by mixing a precursor with the hydrophilic material, followed by purification and calcination, to create a uniform coating that enhances dispersion and bonding, reducing irreversible reactions and improving electrolyte impregnation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbon-based material is used as anode active material, then high energy density and long cycle span are achieved, but hydrophobicity causes low miscibility with hydrophilic solvent and complex electrolyte impregnation
Solution Approach 1:
The patent applies composite materials by combining carbon-based anode active material with hydrophilic materials (such as metal oxides, hydroxides, or salts) to create a composite anode structure. This composite approach maintains the high energy density and long cycle span benefits of carbon-based materials while introducing hydrophilic properties that enable easy electrolyte impregnation without complex procedures.
2Reliability
If a carbon-based material is used as anode active material, then high energy density is achieved, but hydrophobicity reduces dispersion uniformity of solid components in slurry preparation
Solution Approach 1:
The patent uses composite materials by integrating hydrophilic components with carbon-based anode material. The hydrophilic materials in the composite structure improve the wettability and dispersion uniformity of solid components in the slurry, while the carbon-based component maintains high energy density. This results in a uniformly dispersed slurry that is easy to process.
3Reliability
If SEI layer is formed on carbon-based anode active material surface, then initial irreversible reaction occurs, but repeated removal and reformation depletes electrolyte and reduces battery capacity
Solution Approach 1:
The patent applies composite materials where hydrophilic materials (metal oxides, hydroxides, or salts) are combined with carbon-based anode material. These hydrophilic components facilitate the formation of a stable SEI layer during initial activation, preventing repeated breakdown and reformation. This stable SEI layer reduces electrolyte depletion and maintains battery capacity over repeated charge/discharge cycles.
4Ease of manufacture
If surfactant is added as additive to anode or electrolyte, then hydrophobicity problems are addressed, but side effects on operating properties occur
Solution Approach 1:
The patent uses composite materials by incorporating hydrophilic materials directly into the anode structure rather than adding surfactants. This approach addresses the hydrophobicity problem and improves miscibility with hydrophilic solvents and electrolyte impregnation without introducing the side effects that surfactants have on battery operating properties such as cycle life and capacity retention.
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 results in improved uniformity of the anode active material, reducing internal resistance, increasing battery productivity, and maintaining capacity over repeated charge/discharge cycles by forming a strong SEI layer and minimizing electrolyte depletion.
Implementation Method 1
calcining the core-shell precursor to carbonize the material for preparing the at least one material selected from the group consisting of low crystalline carbon and amorphous carbon into the at least one material selected from the group consisting of low crystalline carbon and amorphous carbon
Data Source
AI summary
Disclosed is a method including (a) mixing a precursor of a material for preparing at least one material selected from the group consisting of low crystalline carbon and amorphous carbon with a hydrophilic material, 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 in which the mixture for coating is coated on a core including a crystalline carbon-based material, and (c) calcining the core-shell precursor to carbonize the material for preparing the at least one material selected from the group consisting of low crystalline carbon and amorphous carbon into the at least one material selected from the group consisting of low crystalline carbon and amorphous carbon.