Carbon-Coated Silicon Anode Material for Low-Gas Battery Cycling
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Solution Overview
Problem
Existing silicon-based anode materials for lithium-ion batteries suffer from surface coating layer instability, leading to increased gas production, expansion, and reduced capacity, which deteriorates their performance over cycles.
Innovation Solution
An anode material with a carbon coating layer on a core body, characterized by a residual carbon rate of less than 20% and controlled gas production, enhances the stability and conductivity of the anode, thereby improving the cycle stability and efficiency of the secondary battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a carbon coating layer is applied to silicon-based anode materials to improve stability and reduce expansion, then the cycle stability and structural integrity are improved, but the electrical conductivity and capacity may be reduced due to excessive carbon content
Solution Approach 1:
The patent applies parameter changes by precisely controlling the carbon coating thickness (10-500 nm) and residual carbon rate (≤20%) to optimize the balance between stability and conductivity. This quantitative control transforms the carbon coating from a potentially harmful thick layer into a beneficial thin protective layer that maintains electrical performance while providing structural stability.
Solution Approach 2:
The patent creates a composite structure combining silicon-based active material with a controlled carbon coating layer. This composite approach leverages the high capacity of silicon while using carbon to provide structural stability and conductivity, achieving synergistic effects that overcome the limitations of pure silicon anodes.
2Object-affected harmful factors
If the carbon coating layer thickness is increased to reduce gas production and improve protection, then the expansion resistance and structural stability are improved, but the electrical conductivity deteriorates
Solution Approach 1:
The patent resolves this contradiction by changing the thickness parameter of the carbon coating to a specific range (10-500 nm) that is sufficient to reduce gas production and provide protection while remaining thin enough to maintain electrical conductivity. This precise parameter control allows simultaneous achievement of both protection and conductivity.
Solution Approach 2:
The patent ensures continuous useful action by maintaining a residual carbon rate of ≤20%, which guarantees that sufficient conductive pathways remain intact throughout the anode structure. This continuous carbon network preserves electrical conductivity while the coating provides ongoing protection against gas production and expansion.
3Reliability
If the residual carbon rate is increased to maintain conductivity, then the electrical conductivity is improved, but the protection effect and expansion resistance are reduced
Solution Approach 1:
The patent resolves this contradiction by optimizing the residual carbon rate parameter to ≤20%, which is the threshold value that simultaneously provides adequate protection effect and maintains sufficient electrical conductivity. This optimized parameter balance allows the carbon coating to fulfill both protective and conductive functions.
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 carbon coating layer provides protection to the core body, reducing gas production and expansion, maintaining electrical conductivity, and enhancing the charge and discharge efficiency of the battery, thus improving its capacity and cycle stability.
Implementation Method 1
A 10-day gas production A of the anode material is less than or equal to 100 mL/kg
Implementation Method 2
secondary battery, which includes a shell, an electrode assembly and an electrolyte solution
Data Source
Figure 1A~1B
AI summary
Provided is an anode material, a negative electrode plate and a secondary battery. The anode material includes a core body and a carbon coating layer that coats at least a partial surface of the core body, and the core body includes a matrix and an active substance. A 10-day gas production A of the anode material is less than or equal to 100 mL/kg, and the 10-day gas production A is measured by a drainage method. A residual carbon rate of the anode material is γ=m3−m2m1×100%, which is less than or equal to 20%. The secondary battery based on the above anode material has lower electrode plate expansion rate, great capacity and cycle stability.