Silicon-Embedded Sodium Silicate Matrix for Battery Anodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion batteries using silicon particles as negative electrode active material face deterioration in charge/discharge cycle characteristics due to large volume changes during reactions, leading to particle structure breakage.
Innovation Solution
A negative electrode active material comprising composite particles with a sodium silicate phase having a Vickers hardness of 150 Hv or more, dispersing silicon particles to reduce volume changes and prevent particle structure breakage, while maintaining satisfactory lithium ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon particles are used as negative electrode active material to increase lithium ion intercalation capacity, then the battery capacity is improved, but the charge/discharge cycle characteristics deteriorate due to large volume changes causing particle structure breakage
Solution Approach 1:
The patent uses a composite material system consisting of silicon particles dispersed in a sodium silicate glassy phase matrix. This composite structure allows the silicon to provide high lithium ion intercalation capacity while the glassy phase matrix accommodates volume changes and prevents particle breakage, thus maintaining charge/discharge cycle characteristics.
Solution Approach 2:
The patent controls the Vickers hardness of the sodium silicate glassy phase to be 150 Hv or more, which is a critical parameter change. This hardness threshold ensures the matrix is rigid enough to maintain structural integrity during volume changes but still allows lithium ion diffusion, thereby preventing particle breakage while maintaining electrochemical performance.
2Strength
If the sodium silicate phase hardness is increased to prevent particle structure breakage, then the structural stability is improved, but the lithium ionic conductivity may deteriorate
Solution Approach 1:
The patent precisely controls the Vickers hardness parameter of the sodium silicate glassy phase to be 150 Hv or more. This parameter optimization ensures the matrix has sufficient mechanical strength to prevent particle breakage while maintaining adequate lithium ionic conductivity for electrochemical performance.
Solution Approach 2:
The patent creates a matrix with specific local properties - the sodium silicate glassy phase has optimized hardness and compositional characteristics that provide both structural support and ion conduction pathways. The local quality of the glassy phase matrix is tailored to simultaneously achieve structural stability and ionic conductivity.
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 prevents deterioration in charge/discharge cycle characteristics by minimizing volume changes and ensuring smooth lithium ion migration, enhancing the battery's performance and longevity.
Implementation Method 1
Dispersion of the silicon particles in the sodium silicate phase having a Vickers hardness of 150 Hv or more reduces a volume change in the silicon particles associated with the charge/discharge reaction to thereby prevent the breakage of the particle structure
Implementation Method 2
The sodium silicate phase has low reactivity with lithium ions and exhibits satisfactory lithium ionic conductive property. Thus, the volume change in the sodium silicate phase itself is small, and lithium ions are conceived to migrate relatively smoothly in the sodium silicate phase
Data Source
AI summary
Negative electrode active material particles according to the present invention have composite particles that include: a sodium silicate phase with a Vickers hardness of 150 Hv or greater, and silicon particles dispersed in the sodium silicate phase.