Anode Active Material Composite Coating
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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 solvents, non-uniform dispersion, and increased internal resistance, as well as initial irreversible reactions and reduced battery capacity due to the formation and regeneration of the SEI layer.
Innovation Solution
A composite coating layer comprising silicon oxide and low or amorphous carbon is applied to a crystalline carbon-based core, enhancing miscibility with solvents, reducing impregnation time, and forming a strong SEI layer to improve bonding and electrical conductivity, while inhibiting lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If carbon-based material is used as anode active material, then battery energy density is improved, but miscibility with hydrophilic solvent deteriorates and dispersion uniformity decreases
Solution Approach 1:
The patent applies composite materials by combining carbon-based anode active material with hydrophilic inorganic particles (such as metal oxides or hydroxides) to create a composite anode structure. This composite approach allows the carbon material to maintain its high energy density function while the hydrophilic inorganic particles improve miscibility with hydrophilic solvents and enhance dispersion uniformity, thereby resolving the technical contradiction between energy density and compositional stability.
2Use of energy by moving object
If carbon-based material is used as anode active material, then battery energy density is improved, but dispersion uniformity of solid components deteriorates
Solution Approach 1:
The patent uses composite materials by integrating hydrophilic inorganic particles into the carbon-based anode structure. These inorganic particles act as dispersants that improve the uniform distribution of solid components in the slurry, directly addressing the dispersion uniformity issue while preserving the high energy density characteristics of the carbon material.
Solution Approach 2:
The hydrophilic inorganic particles serve as intermediary substances between the carbon-based anode material and the hydrophilic solvent. They facilitate better interaction and distribution, acting as a mediator that enhances dispersion uniformity without compromising the energy storage function of the carbon material.
3Stability of the object's composition
If surfactant is added to improve miscibility, then solvent miscibility is improved, but battery driving properties deteriorate due to side effects
Solution Approach 1:
The patent replaces traditional surfactants with hydrophilic inorganic particles that do not exhibit the harmful side effects of surfactants on battery driving properties. These inorganic particles provide the necessary miscibility improvement without introducing contaminants or substances that could interfere with battery performance, effectively substituting a problematic additive with a benign alternative.
Solution Approach 2:
The hydrophilic inorganic particles serve as a safe intermediary substance that improves solvent miscibility without the harmful side effects associated with surfactants. They mediate between the hydrophobic carbon material and hydrophilic solvent in a way that maintains battery driving properties, unlike surfactants which can cause performance degradation.
4Reliability
If SEI layer is formed on carbon-based anode, then initial charge/discharge activation is achieved, but battery capacity is reduced due to electrolyte exhaustion
Solution Approach 1:
The patent employs composite materials by combining carbon-based anode material with hydrophilic inorganic particles. This composite structure modifies the SEI layer formation process, allowing for more controlled and stable SEI development that consumes less electrolyte. The inorganic particles contribute to forming a more stable interface that reduces continuous SEI regeneration, thereby preserving battery capacity while maintaining activation functionality.
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
This solution improves the uniformity and bonding of anode components, reduces internal resistance, extends battery lifespan, and maintains high charge/discharge capacity over multiple cycles by forming a strong SEI layer and preventing lithium precipitation.
Implementation Method 1
a composite coating layer comprising one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon, and silicon oxide capable of intercalating and deintercalating ions
Implementation Method 2
the carbon-based anode active material induces initial irreversible reaction, since a solid electrolyte interface (SEI) layer is formed on the surface of the carbon-based anode active material during an initial charge/discharge process (activation process)
Data Source
AI summary
Disclosed are an anode active material for secondary batteries, capable of intercalating and deintercalating ions, the anode active material including a core including a crystalline carbon-based material, and a composite coating layer including one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon, and silicon oxide capable of intercalating and deintercalating ions, wherein the composite coating layer includes a matrix comprising one component selected from (a) the one or more materials selected from the group consisting of low crystalline carbon and amorphous carbon and (b) the silicon oxide capable of intercalating and deintercalating ions, and a filler including the other component, incorporated in the matrix, and a secondary battery including the anode active material.