Silicon Oxide Negative Electrode Active Material for Battery Efficiency
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Solution Overview
Problem
Lithium ion secondary batteries face challenges in achieving high initial charging and discharging efficiency due to the low efficiency of silicon oxide materials, which are prone to structural destruction and irreversible reactions.
Innovation Solution
A negative electrode active material is developed comprising a matrix with elements like silicon, tin, or germanium, and oxygen, where a second element such as copper, boron, or phosphorus bonds with oxygen, forming a cluster dispersed in the matrix, improving the material's structural stability and efficiency through co-vapor deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon oxide (SiOx) is used as a negative electrode active material to achieve higher capacity than carbon-based materials, then the capacity is improved, but the initial charging and discharging efficiency deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of silicon oxide particles embedded in a carbon coating layer. This composite structure combines the high capacity advantage of silicon oxide with the good initial efficiency and structural stability of carbon, resolving the contradiction between capacity and initial charging/discharging efficiency
Solution Approach 2:
The patent applies different materials with different properties to different parts of the electrode structure: silicon oxide is used in the core particles for high capacity, while a carbon coating layer is applied on the surface for structural stability and efficient lithium ion transport. This local differentiation resolves the contradiction by optimizing each region for its specific function
2Quantity of substance
If silicon oxide (SiOx) is used to attain higher capacity, then the capacity is improved, but the structural stability deteriorates due to swelling and shrinking
Solution Approach 1:
The patent creates a composite structure where silicon oxide particles are embedded in a carbon coating layer. The carbon layer acts as a protective shell that constrains the silicon oxide particles during lithium ion insertion and extraction, preventing structural destruction from swelling and shrinking while maintaining the high capacity benefit
Solution Approach 2:
The carbon coating layer is applied beforehand to the silicon oxide particles, creating a protective buffer that absorbs and distributes the mechanical stress from volume changes during charging and discharging. This pre-applied protective layer prevents structural destruction before it can occur
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 solution enhances the initial charging and discharging efficiency and cycle property of the battery by stabilizing the structure and preventing lithium loss, while also improving safety and electron conductivity.
Implementation Method 1
thermally vaporizing a material including at least a first element selected from the group consisting of silicon, tin, and germanium, oxide
Data Source
AI summary
A negative electrode active material includes a matrix including at least a first element selected from the group consisting of silicon, tin, and germanium, at least a second element selected from the group consisting of copper, boron, phosphorous, aluminum, gallium, arsenic, antimony, lithium, and sodium, and oxygen. The second element bonds with oxygen; and a cluster includes the first element and is dispersed in the matrix.