Silicon Anode Whisker Control via Patterned Metal Catalyst
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Solution Overview
Problem
Silicon-based power storage devices face deterioration due to volume expansion during charging, leading to poor charge-discharge cycle characteristics, as the active material separates from the current collector.
Innovation Solution
A power storage device design featuring a current collector with alternating metal layers and a crystalline silicon active material layer, where the metal layers have specific intervals and shapes to control whisker growth, reducing stress and enhancing interface characteristics through mixed regions and metal oxide formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as active material to increase capacity, then discharge capacity is improved, but volume expansion causes active material to separate from current collector during charging
Solution Approach 1:
The current collector surface is divided into multiple regions by forming insulating films in specific patterns, creating isolated contact regions between the silicon active material and current collector. This segmentation prevents continuous stress propagation and maintains electrical connection even during volume expansion.
Solution Approach 2:
The insulating film is formed selectively in specific regions rather than uniformly across the entire current collector surface. This creates local variations in adhesion properties, allowing the silicon to expand freely in certain areas while maintaining contact in others, thus resolving the contradiction between capacity and cycle stability.
2Reliability
If metal layers are added to control whisker growth and improve adhesion, then interface characteristics are improved, but device structure becomes more complex
Solution Approach 1:
The insulating film serves multiple functions simultaneously: it controls whisker growth, manages adhesion between layers, and provides electrical isolation in specific regions. This multi-functionality reduces the need for additional specialized components, thereby limiting complexity increase while achieving multiple objectives.
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 design enhances the discharge capacity and endurance of power storage devices by minimizing material separation and improving electrical conductivity and adhesion, thus extending the cycle life.
Implementation Method 1
a plurality of metal layers which is provided over the current collector and includes a second metal element which is different from the first metal element... The active material layer includes a whisker group selectively in a region which is in contact with the metal layer
Implementation Method 2
A mixed region of a metal element and silicon may be formed in a region of the current collector in an interface with the active material layer and its vicinity or in a region of the metal layer in an interface with the active material layer and its vicinity
Implementation Method 3
a metal oxide region may be provided in the current collector or the metal layer between the mixed region and the active material layer
Data Source
AI summary
An electrode for a power storage device with less deterioration due to charge and discharge and a power storage device using the electrode are provided. In the electrode for a power storage device and the power storage device, a region including a metal element which functions as a catalyst is selectively provided over a current collector, and then, an active material layer is formed. By selectively providing the region including the metal element, a whisker can be effectively generated in the active material layer over the current collector, and the whisker generation region can be controlled. Accordingly, the discharge capacity can be increased and the cycle characteristics can be improved.