Porous Silicon Electrode with Copper Layer for Lithium-Ion Battery
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Solution Overview
Problem
Lithium-ion batteries using graphite anodes have limited specific charging capacity and are prone to destruction due to lithium intercalation-induced volume expansion, while silicon-based electrodes offer higher capacity but face similar expansion issues, leading to short service life.
Innovation Solution
A porous silicon electrode with a copper layer is developed, allowing silicon to expand into pores without damage, enhancing charging capacity and service life, and a cost-effective production process involving wet-chemical etching and electrochemical deposition is used.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as electrode material to achieve high specific charging capacity, then the lithium-uptake capacity increases, but the volume expansion during intercalation leads to electrode destruction
Solution Approach 1:
The patent applies porous silicon as the electrode material, where the porous structure provides internal void space that can accommodate volume expansion during lithium intercalation. The pores act as buffers that absorb the mechanical stress of expansion without causing structural collapse or electrode destruction, thereby maintaining reliability while enabling high lithium capacity.
Solution Approach 2:
The patent modifies the physical structure of silicon by creating a porous morphology with controlled pore sizes and distributions. This parameter change transforms solid silicon into porous silicon, which fundamentally alters the mechanical response to lithium insertion by providing expansion pathways within the pore structures rather than causing external swelling.
2Ease of manufacture
If conventional electrode production methods are used, then the manufacturing process is simple, but the production cost is high due to masking and multi-stage etching steps
Solution Approach 1:
The patent removes the masking step from the conventional multi-stage etching process. By using a single-stage etching method that directly creates the desired porous structure without requiring protective masks, the process becomes simpler and more cost-effective while maintaining the ability to produce high-quality porous silicon electrodes.
Solution Approach 2:
The patent employs a pre-treatment step on the silicon substrate before etching that facilitates the formation of porous structures in a single etching stage. This preliminary modification of the substrate surface or composition enables the subsequent single-stage etching to produce the desired porous morphology without requiring complex multi-stage processes or masking.
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 porous silicon-copper electrode achieves a high specific charging capacity and long service life by accommodating volume expansion, while the production process ensures low costs and mechanical flexibility.
Implementation Method 1
silicon has the disadvantage compared to graphite that intercalation of lithium results in a substantial expansion in volume of the silicon
Implementation Method 2
depositing a copper layer on the at least one porous silicon layer
Implementation Method 3
forming at least one porous silicon layer by etching of a silicon substrate
Data Source
AI summary
An electrode for a lithium-ion battery. The electrode has at least one porous silicon layer and a copper layer. There is also described a battery with such an electrode, a method for producing an electrode of this kind, and the use of an electrode of this kind in a battery.