Carbon-Coated Silicon Oxide Anode Material With Roughness-Controlled Surface
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Solution Overview
Problem
Carbon-based negative electrode active materials in lithium secondary batteries have limited theoretical capacity, hindering the development of high-capacity and high-power secondary batteries.
Innovation Solution
A silicon-based oxide particle coated with a carbon coating layer having a surface roughness of 4 nm to 30 nm, combined with a carbon-based active material, to enhance electrical conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a carbon-based negative electrode active material is used, then the battery can be manufactured with conventional materials and processes, but the theoretical capacity is limited and high-capacity batteries cannot be achieved
Solution Approach 1:
The patent uses a composite material structure where silicon-based oxide particles are coated with a carbon layer. The silicon-based oxide provides high theoretical capacity while the carbon coating ensures compatibility with conventional battery systems and provides structural stability, thus resolving the contradiction between achieving high capacity and maintaining material compatibility.
Solution Approach 2:
The patent changes the material parameter from conventional carbon-based materials to silicon-based oxide materials, which have higher theoretical capacity. This parameter change enables high-capacity battery manufacturing while the carbon coating maintains compatibility with existing processes.
2Quantity of substance
If a silicon-based oxide particle with carbon coating is used, then high capacity and excellent charge/discharge characteristics are achieved, but the surface roughness must be precisely controlled
Solution Approach 1:
The patent identifies surface roughness as a critical parameter and specifies a precise range (4-30 nm) to optimize both discharge capacity and charge/discharge characteristics. This parameter control resolves the contradiction by establishing specific roughness thresholds that balance high capacity with manufacturing feasibility.
3Shape
If the carbon coating layer has very low surface roughness, then smooth surface is achieved, but electrical conductivity and stability are reduced
Solution Approach 1:
The patent establishes a minimum surface roughness threshold of 4 nm to ensure adequate electrical conductivity and stability. This parameter specification resolves the contradiction by preventing excessively smooth surfaces that would compromise electrical performance while still maintaining relatively smooth morphology.
4Reliability
If the carbon coating layer has very high surface roughness, then electrical conductivity is enhanced, but structural stability deteriorates
Solution Approach 1:
The patent sets a maximum surface roughness limit of 30 nm to maintain structural stability while still providing sufficient electrical conductivity. This upper bound prevents excessive roughness that would compromise the structural integrity of the electrode material.
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 discharge capacity, initial efficiency, rate characteristics, and storage capacity of secondary batteries, while maintaining structural stability.
Implementation Method 1
a carbon coating layer which coats at least a portion of the silicon-based oxide particle
Implementation Method 2
The silicon-based oxide particle may be doped with at least one metal selected from the group consisting of Mg, Li, Al, Ca, Ti, and V
Data Source
AI summary
The present disclosure relates to a negative electrode active material for a secondary battery, including a silicon-based oxide particle, and a carbon coating layer coating at least a portion of the silicon-based oxide particle, in which the carbon coating layer has a surface roughness of greater than or equal to 4 nm and less than or equal to 30 nm.