Passivated Silicon Anode Particles for Water-Based Slurry Processing
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Solution Overview
Problem
Silicon anode materials for lithium ion batteries offer larger capacity but are reactive and require careful handling in non-oxidizing environments, limiting their practical application in oxidizing environments like water-based slurries.
Innovation Solution
A mixture of silicon particles with nanoparticles and a carbon-based binder/surfactant is formed, reduced to create coated silicon particles with a passivation layer, allowing for the formation of an anode that can be processed in oxidizing environments, such as water-based slurries, using metalloid oxide, metalloid salt, or carbon nanoparticles as nucleation sites for the passivation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon particles are used as anode material, then battery capacity is improved, but reactivity in oxidizing environments worsens
Solution Approach 1:
The patent creates a composite structure where silicon particles are coated with a passivation layer formed from metalloid oxide/salt nanoparticles. This composite approach combines the high capacity of silicon with the protective properties of the passivation layer, enabling stable performance in oxidizing environments while maintaining high battery capacity
Solution Approach 2:
The passivation layer acts as an intermediary between the silicon particles and the oxidizing environment. This intermediate layer prevents direct contact and reaction between silicon and oxygen/water, allowing silicon to function in previously incompatible environments
2Reliability
If passivation coating is applied to silicon particles, then stability in oxidizing environment is improved, but manufacturing complexity worsens
Solution Approach 1:
The metalloid oxide/salt nanoparticles serve a dual function: they act as reducing agents that automatically form the passivation coating on silicon particles during the mixing process, and they become part of the final protective layer. This self-service mechanism eliminates the need for separate coating equipment and complex multi-step processes
Solution Approach 2:
The patent changes the chemical state of the metalloid nanoparticles from oxidized (oxide/salt form) to reduced (metallic form) during mixing, which simultaneously creates the passivation layer. This parameter change approach transforms a potential manufacturing complexity into a simplified one-step process
3Reliability
If conventional handling procedures are used for silicon, then purity is maintained, but productivity worsens
Solution Approach 1:
The passivation layer formed from metalloid nanoparticles acts as a protective intermediary that allows silicon particles to be handled in conventional oxidizing environments (air, water-based slurries) without compromising purity. This eliminates the need for specialized non-oxidizing atmosphere handling equipment and procedures
Solution Approach 2:
The passivation layer creates an effective inert environment around each silicon particle, allowing bulk handling in air or water-based environments. This transforms the requirement for specialized inert atmosphere handling into a simple mixing and coating process, dramatically improving productivity
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 passivation layer prevents oxidation of silicon particles, enabling efficient and simplified anode production in oxidizing environments, enhancing the scalability and performance of lithium ion batteries for fast charging applications.
Implementation Method 1
coated silicon particles having a passivation coating, and consolidating the reduced mixture to form an anode
Implementation Method 2
reducing the mixture to yield a reduced mixture comprising coated silicon particles having a passivation coating
Data Source
AI summary
Methods, anode material particles, mixtures, anodes and lithium-ion batteries are provided, having passivated silicon-based particles that enable processing in oxidizing environments such as water-based slurries. Methods comprise forming a mixture of silicon particles with nanoparticles (NPs) and a carbon-based binders and/or surfactants, wherein the NPs comprise at least one of: metalloid oxide NPs, metalloid salt NPs and carbon NPs, reducing the mixture to yield a reduced mixture comprising coated silicon particles with a coating providing a passivation layer (possibly amorphous), and consolidating the reduced mixture to form an anode. It is suggested that the NPs provide nucleation sites for the passivation layer on the surface of the silicon particles—enabling significant anode-formation process simplifications such as using water-based slurries—enabled by disclosed methods and anode active material particles.