Silicon Germanium Electrode {110} Orientation
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Solution Overview
Problem
The volume expansion and contraction of silicon active materials in energy storage devices, such as lithium-ion batteries, lead to mechanical damage and deterioration of charge-discharge cycle characteristics, limiting their capacity and endurance.
Innovation Solution
The use of a crystalline semiconductor film with a {110} crystal plane, containing silicon and germanium, as the active material, which is formed over a current collector through a crystallization process, enhances the orientation ratio and conductivity, reducing deterioration and increasing discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon active material is used to increase capacity, then the capacity of the energy storage device is improved, but the volume expansion and contraction cause mechanical damage and deteriorate charge-discharge cycle characteristics
Solution Approach 1:
The patent changes the crystal orientation parameter of silicon from random or other orientations to specifically the {110} crystal plane orientation. This parameter change reduces volume expansion during lithiation while maintaining high capacity, thereby improving charge-discharge cycle characteristics without sacrificing capacity.
Solution Approach 2:
The patent uses composite materials by forming a crystalline semiconductor film containing silicon and germanium (SiGe) with specific crystal orientation. The germanium addition modifies the crystal structure to achieve the desired {110} orientation and reduce volume expansion, creating a composite material that maintains high capacity while improving cycle stability.
2Reliability
If crystalline semiconductor film with {110} crystal plane is used, then charge-discharge cycle characteristics are improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing laser irradiation or heat treatment during the manufacturing process to pre-establish the {110} crystal orientation before the electrode is assembled into the energy storage device. This preliminary crystallization step ensures the desired crystal structure is achieved during manufacturing, simplifying subsequent processing and ensuring consistent performance.
Solution Approach 2:
The patent replaces mechanical crystal orientation methods with field-based methods such as laser irradiation or thermal field treatment. This substitution allows for precise control of crystal orientation without complex mechanical alignment equipment, reducing manufacturing process complexity while achieving the desired {110} crystal plane orientation.
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
This approach results in an electrode with reduced deterioration due to charge and discharge cycles, achieving higher capacity and endurance for energy storage devices by utilizing a crystalline semiconductor film with a high orientation ratio on the {110} plane, specifically with silicon and germanium, and a metal element, promoting conductivity and oxidation-reduction reactions.
Implementation Method 1
conducting a crystallization process by irradiation with a laser beam
Implementation Method 2
forming as an active material a crystalline semiconductor film having a {110} crystal plane
Implementation Method 3
promoting conductivity and oxidation-reduction reactions
Data Source
AI summary
An electrode for an energy storage device with less deterioration due to charge and discharge, and a method for manufacturing thereof are provided. Further, an energy storage device having large capacity and high endurance can be provided. In an electrode of an energy storage device in which an active material is formed over a current collector, the surface of the active material is formed of a crystalline semiconductor film having a {110} crystal plane. The crystalline semiconductor film having a {110} crystal plane may be a crystalline silicon film containing a metal element which reacts with silicon to form a silicide. Alternatively, the crystalline semiconductor film having a {110} crystal plane may be a crystalline semiconductor film containing silicon as its main component and also containing germanium and a metal element which reacts with silicon to form a silicide.