Polymer-Coated Silicon Anode Particles for Low-Hydrogen Slurry Mixing
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Solution Overview
Problem
The production of hydrogen gas during the mixing of a negative electrode slurry in silicon-based particles, which can lead to safety hazards due to its combustible and explosive nature, and the inability of carbon coating layers to effectively block moisture ingress and oxygen penetration, compromising the integrity of the negative electrode.
Innovation Solution
A negative electrode active material particle is developed with a core composed of silicon-based particles and a coating layer made of a polymer containing an aromatic cyclic monomer unit with a heteroatom and an alkyl group at a side chain, which suppresses the reaction with water during aqueous mixing, thereby minimizing hydrogen gas production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon-based particles are mixed using water as a solvent in negative electrode slurry, then the negative electrode can be formed, but hydrogen gas is produced through reaction between silicon-based particles and water, creating safety hazards
Solution Approach 1:
A coating layer comprising a polymer including an aromatic cyclic monomer unit including a heteroatom and having an alkyl group at a side chain is formed on the silicon-based particle to act as an intermediary barrier. This coating layer prevents direct contact between water and silicon-based particles during aqueous mixing, thereby suppressing hydrogen gas production while allowing the mixing process to proceed
Solution Approach 2:
The negative electrode active material particle is constructed as a composite structure with a core comprising a silicon-based particle and a coating layer comprising a polymer including an aromatic cyclic monomer unit including a heteroatom and having an alkyl group at a side chain. This composite structure combines the high capacity benefits of silicon-based particles with the protective properties of the polymer coating
2Reliability
If a carbon coating layer is formed on silicon-based particles to prevent defects, then particle protection is improved, but over time humidity penetrates through the carbon coating layer or oxygen enters through cracks, failing to effectively block contact between moisture and silicon-based particles
Solution Approach 1:
The patent changes the chemical composition and structural parameters of the coating layer from conventional carbon-based materials to a polymer including an aromatic cyclic monomer unit including a heteroatom and having an alkyl group at a side chain. This parameter change creates a more stable and effective barrier against humidity and oxygen penetration over time
Solution Approach 2:
The coating layer is designed with specific local chemical properties through the aromatic cyclic monomer unit including a heteroatom and having an alkyl group at a side chain, providing enhanced local resistance to humidity and oxygen at the interface with silicon-based particles
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 effectively reduces hydrogen gas production, enhances safety during manufacturing and battery operation, and improves conductivity and adhesiveness, leading to improved battery performance and longevity.
Implementation Method 1
the coating layer comprises a polymer comprising an aromatic cyclic monomer unit comprising a heteroatom and having an alkyl group at a side chain... suppresses the reaction with water during aqueous mixing, thereby minimizing hydrogen gas production
Data Source
AI summary
A negative electrode active material particle, a negative electrode comprising the same, and a secondary battery comprising the negative electrode are provided. The negative electrode active material particle comprises a core and a coating layer on the core, the core comprising a silicon-based particle, and the coating layer comprising a polymer comprising an aromatic cyclic monomer unit including a heteroatom and having an alkyl group at a side chain, and thereby prevents side reactions such as the production of hydrogen gas during aqueous mixing of a slurry without increase of resistance.