Electrode with Dendritic Protrusions for Adhesion
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Solution Overview
Problem
Current collectors in electrochemical devices are prone to corrosion and exhibit poor adhesion of active material, leading to increased resistance and contamination, as well as delamination issues during charge and discharge cycling.
Innovation Solution
A substrate with a metal shell encapsulating a current collector and featuring dendritic columnar growths with protrusions is used, which penetrates the active material to form a mechanical retainer and creates localized regions of increased current density for improved adhesion and electrochemical deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is added to protect the current collector from corrosion, then corrosion resistance is improved, but device complexity increases
Solution Approach 1:
The current collector is designed as a composite structure with a metal shell encapsulating the base current collector material. This composite structure provides corrosion protection while maintaining electrical conductivity and mechanical strength, resolving the contradiction between reliability and structural simplicity.
Solution Approach 2:
The metal shell is nested around the current collector, creating a protective enclosure. This nesting approach provides corrosion protection without requiring separate protective layers or complex coating processes, thus improving reliability while minimizing added complexity.
2Ease of manufacture
If the active material is applied directly to the current collector, then manufacturing is simpler, but adhesion is poor leading to delamination
Solution Approach 1:
The surface of the metal shell is engineered with dendritic columnar growths that create localized high-surface-area regions. These structures provide enhanced mechanical interlocking with the active material while the rest of the shell maintains a smoother morphology, thus improving adhesion without complicating the overall manufacturing process.
Solution Approach 2:
The dendritic columnar growths feature curved and branched surfaces that increase the effective contact area between the current collector and active material. This curvature-based surface modification enhances adhesion strength while maintaining a relatively simple fabrication approach.
3Reliability
If dendritic columnar growths are formed on the metal shell, then adhesion and current density distribution are improved, but manufacturing complexity increases
Solution Approach 1:
The dendritic columnar growths are formed through electrochemical processes during electrode fabrication, where the structure self-organizes based on local current density distributions. This self-forming mechanism reduces the need for complex post-processing or precise control of growth parameters, thus improving adhesion while limiting manufacturing complexity.
4Reliability
If the protrusions penetrate the active material to form mechanical retainers, then delamination resistance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The dendritic columnar growths and their protrusions are designed to dynamically adapt during electrode fabrication and cycling. The structures flex and deform to accommodate variations in active material application thickness, reducing the need for precise control of penetration depth while maintaining delamination resistance.
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 configuration enhances mechanical and electrochemical adhesion, reduces interfacial impedance, and results in a more robust electrode with improved performance and reduced delamination, maintaining electrical contact and protecting the current collector from corrosion.
Implementation Method 1
define localized regions of increased current density during operation of the electrode that promote deposition of the active material first on the protrusions
Implementation Method 2
The protrusions penetrate the active material to form a mechanical retainer that prevents delamination of the active material from the metal shell
Implementation Method 3
a metal shell in direct contact with and encapsulating the current collector
Data Source
AI summary
An electrode includes a current collector, a metal shell in direct contact with and encapsulating the current collector, green dendritic columnar growths extending out of the metal shell and having protrusions thereon, and active material in contact with the metal shell and having embedded therein the green dendritic columnar growths. The protrusions penetrate the active material to form a mechanical retainer that prevents delamination of the active material from the metal shell and define localized regions of increased current density during operation of the electrode that promote deposition of the active material first on the protrusions and then on areas of the green dendritic columnar growths adjacent to the protrusions such that the active material electrochemically adheres to the green dendritic columnar growths and the protrusions enlarge during repeated charge and discharge cycling of the electrode.