Porous Silicon Anode Material to Suppress SEI Growth
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Solution Overview
Problem
Rechargeable lithium batteries using silicon-based negative electrode active materials face issues with excessive film formation on the surface during charging and discharging, leading to mechanical damage and rapid degradation of cycle-life characteristics.
Innovation Solution
A negative electrode active material comprising a porous substrate of zeolite with amorphous silicon filled in its pores, which suppresses excessive film growth and enhances cycle-life characteristics by controlling volume expansion and improving electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based active material is used to increase capacity, then electrochemical capacity is improved, but excessive film formation occurs on the surface during charging and discharging
Solution Approach 1:
The patent uses a porous substrate with controlled pore structure to fill amorphous silicon. The porous structure provides accommodation space for silicon volume expansion during lithiation, preventing excessive film formation on the silicon surface while maintaining high electrochemical capacity. The pores act as buffer spaces that absorb expansion stress without transmitting it to the surrounding electrolyte interface.
Solution Approach 2:
The patent creates a composite structure combining amorphous silicon with a porous substrate material. This composite approach allows the silicon to provide high capacity while the porous substrate provides structural stability and controls film formation. The composite structure synergistically combines the advantages of both materials to resolve the contradiction between capacity and film formation.
2Quantity of substance
If silicon-based active material is used to increase capacity, then battery capacity is improved, but cycle-life characteristics deteriorate due to violent expansion and contraction
Solution Approach 1:
The porous substrate provides a three-dimensional network structure that accommodates silicon expansion and contraction during charge-discharge cycles. This prevents particle breakage and maintains structural integrity over many cycles, significantly improving cycle-life characteristics while preserving the high capacity benefits of silicon.
Solution Approach 2:
The porous substrate structure provides pre-established cushioning space within its pores to absorb the expansion stress of silicon during lithiation. This beforehand cushioning prevents mechanical damage to silicon particles during subsequent cycling, maintaining electrode integrity and extending battery cycle life.
3Stability of the object's composition
If conventional carbon-based active material is used, then structural stability is maintained, but electrochemical capacity is limited
Solution Approach 1:
The patent combines amorphous silicon (high capacity) with porous substrate material (structural stability) to create a composite that achieves both high electrochemical capacity and structural stability. The porous substrate maintains structural integrity while the silicon provides high capacity, resolving the trade-off between stability and capacity.
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 proposed structure effectively minimizes SEI film generation, improves battery capacity, and extends the cycle-life of rechargeable lithium batteries by preventing particle breakage and enhancing electronic conductivity.
Implementation Method 1
silicon, which provided for a greater amount of lithium intercalation/deintercalation than conventional carbon-based active materials
Implementation Method 2
a porous substrate including a zeolite of Chemical Formula 1; and amorphous silicon filled in pores of the porous substrate
Data Source
AI summary
A negative electrode active material includes a porous substrate including a zeolite and amorphous silicon filled in pores of the porous substrate. The negative electrode active material effectively suppresses SEI generation, has very high capacity, and has excellent battery cycle-life characteristics.