Silicon Clathrate Anode Composition for Low-Expansion Li-Ion Batteries
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Solution Overview
Problem
Silicon clathrate electrode active materials in lithium-ion batteries experience significant expansion during charging, and there is a need for further suppression of this expansion, especially during repeated charging-discharging cycles.
Innovation Solution
An active material comprising a specific ratio of type I silicon clathrate to type II silicon clathrate, within the range of 0.01% to 53% by content ratio, which is thermodynamically stable and porous, allowing for reduced expansion and improved structural stability during lithium-ion insertion, thereby minimizing volume change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If silicon clathrate electrode active material is used, then expansion during charging is suppressed compared to conventional silicon electrode active materials, but further suppression of expansion is still needed for improved performance
Solution Approach 1:
The invention changes the compositional parameter by controlling the ratio of type I silicon clathrate to type II silicon clathrate within a specific range (0.01% to 53%). This parameter optimization achieves further expansion suppression beyond what conventional silicon clathrate materials can provide, while maintaining structural stability during charging-discharging cycles.
Solution Approach 2:
The invention creates a composite electrode active material comprising both type I silicon clathrate and type II silicon clathrate in a controlled ratio. This composite structure combines the advantages of both crystal phases to achieve superior expansion suppression and capacity retention compared to using a single crystal phase alone.
2Quantity of substance
If silicon electrode active material is used for high energy densification, then battery energy density is improved, but large expansion occurs during charging
Solution Approach 1:
By optimizing the ratio parameter of type I to type II silicon clathrate (0.01% to 53%), the invention achieves a balance between maintaining high energy density and suppressing charging expansion. The controlled compositional ratio allows the material to accommodate lithium ions while minimizing volume increase.
Solution Approach 2:
The invention utilizes porous silicon clathrate structures that provide internal void space to accommodate expansion during lithium-ion insertion. The porous architecture allows the material to absorb expansion stress internally, reducing external volume increase while maintaining high capacity.
3Stability of the object's composition
If silicon clathrate is used to suppress expansion, then charging stability is improved, but non-expansion region retention rate decreases with repeated charging-discharging
Solution Approach 1:
The composite structure of type I and type II silicon clathrate in controlled ratios provides both immediate charging stability and long-term capacity retention. The synergistic combination of crystal phases ensures structural integrity is maintained throughout repeated charging-discharging cycles, preventing degradation.
Solution Approach 2:
Optimizing the crystal phase composition ratio (0.01% to 53% type I relative to type II) creates a material with enhanced structural stability that resists degradation during cycling. This parameter control ensures both initial charging stability and sustained performance over extended battery life.
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 active material exhibits low expansion during initial charging and maintains a high non-expansion region retention rate even after repeated charging-discharging cycles, enhancing the battery's performance and capacity retention.
Implementation Method 1
silicon clathrate comprising type I silicon clathrate and type II silicon clathrate... allowing for reduced expansion and improved structural stability during lithium-ion insertion
Data Source
AI summary
The present disclosure provides an active material for lithium-ion batteries, having low expansion during initial charging and a high non-expansion region retention rate even with repeated charging-discharging, and a lithium-ion battery comprising such an active material for batteries. The active material for lithium-ion batteries of the present disclosure comprises silicon clathrate comprising type I silicon clathrate and type II silicon clathrate. In the active material for lithium-ion batteries, a ratio of a content ratio of the type I silicon clathrate relative to a content ratio of the type II silicon clathrate is 0.01% or greater and 53% or less. The lithium-ion battery of the present disclosure comprises a negative electrode active material layer, and the negative electrode active material layer comprises the active material for lithium-ion batteries of the present disclosure.