Monolithic Semiconductor Anode with Uniform Ion Transport Structure
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Solution Overview
Problem
Lithium-ion batteries face degradation and capacity loss due to volume changes and stress caused by lithium ion cycling, leading to exfoliation of anode materials from current collectors, especially in monolithic and composite semiconductor anodes.
Innovation Solution
A negative electrode structure with a monolithic semiconductor anode integrated with a uniform ion transport structure that serves as both a current collector and ionic interface, reducing stress through uniform ion distribution and conductivity enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a monolithic semiconductor anode is used to achieve high capacity, then the battery capacity increases, but the anode material undergoes significant volume changes during cycling causing stress and exfoliation from the current collector
Solution Approach 1:
The anode is segmented into multiple thin semiconductor layers deposited on the current collector. This segmentation reduces the volume change stress in each individual layer during lithium ion insertion/extraction cycles, preventing exfoliation while maintaining high overall capacity through the cumulative effect of multiple layers.
Solution Approach 2:
The anode uses composite semiconductor materials with different properties - silicon layers provide high capacity while germanium layers provide structural stability. This composite structure allows the anode to achieve high capacity while the germanium component mitigates volume expansion stress, preventing exfoliation.
2Quantity of substance
If the anode material reacts with lithium ions to increase capacity, then the battery capacity increases, but non-uniform ion distribution causes stress concentration and degradation
Solution Approach 1:
Different semiconductor layers are strategically positioned to create local quality variations - silicon layers are placed where high capacity is needed, while germanium layers are positioned to provide structural support and uniform ion distribution. This local differentiation ensures both high capacity and uniform stress distribution, preventing degradation.
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 uniform ion transport structure mitigates anode degradation by ensuring uniform ion insertion and extraction, reducing stress and maintaining electrical connectivity, thereby enhancing the battery's cycle life and capacity retention.
Implementation Method 1
a uniform ion transport structure disposed at the monolithic anode surface for contacting the non-aqueous electrolyte
Implementation Method 2
Elements like aluminum, silicon, germanium and tin react with lithium ions and are used in high-capacity anodes
Data Source
AI summary
The present invention relates to a negative electrode structure for use in a non-aqueous electrolyte secondary battery and a method of making such negative electrode structure. The negative electrode structure comprises: a monolithic anode comprising a semiconductor material, and a uniform ion transport structure disposed at the monolithic anode surface for contacting a non-aqueous electrolyte, wherein the uniform ion transport structure serves as a current collector and the negative electrode structure does not contain another current collector. The present invention also relates to a battery comprising the negative electrode structure of the present invention, a cathode, and a non-aqueous electrolyte.