Porous Composite Current Collector for Dendrite-Resistant Li-Ion Anodes
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Solution Overview
Problem
Existing lithium-ion batteries using smooth copper foil as the negative electrode face issues with poor adhesion of the active material, uneven distribution of the active material, and the formation of lithium dendrites, which affect the safety and service life of the battery.
Innovation Solution
A composite current collector is introduced, comprising a substrate and two laminated porous conductive sheets with amorphous micropores, which improve the adhesion and uniform distribution of the active material and suppress the formation of lithium dendrites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If smooth copper foil is used as the negative electrode current collector, then the manufacturing process is simple, but the adhesion of the active material is poor and the active material distribution is uneven
Solution Approach 1:
The patent applies porous materials by forming micropores on the surface of the copper foil current collector through chemical etching. These micropores increase the surface area and provide anchoring points for the active material, significantly improving adhesion while maintaining a relatively simple manufacturing process using chemical etchants.
Solution Approach 2:
The patent creates a composite structure by combining copper foil with a porous layer formed through chemical etching. This composite structure integrates the electrical conductivity of copper with the adhesion benefits of the porous surface, resolving the contradiction between manufacturing simplicity and adhesion reliability.
2Ease of manufacture
If smooth copper foil is used as the negative electrode current collector, then the manufacturing cost is low, but lithium dendrites form easily affecting safety
Solution Approach 1:
The microporous structure created through chemical etching provides a three-dimensional surface that promotes uniform lithium ion deposition during charging. This prevents the formation of lithium dendrites by distributing the deposition sites across numerous micropore surfaces, thereby improving safety while maintaining cost-effectiveness.
Solution Approach 2:
The patent changes the surface morphology parameter of the copper foil from smooth to microporous through chemical etching. This parameter change fundamentally alters the deposition behavior of lithium ions, preventing dendrite formation while keeping the base material and manufacturing process cost-effective.
3Reliability
If the surface of the current collector is made rough to improve adhesion, then the adhesion improves, but the active material distribution becomes more difficult to control
Solution Approach 1:
The microporous structure provides uniform distribution of pore sites across the copper foil surface, creating numerous identical anchoring points. This ensures that active material distributes uniformly during coating, as each micropore provides equivalent adhesion sites, thereby maintaining manufacturing precision while improving adhesion.
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 composite current collector enhances the adhesion and uniform distribution of the active material, reduces the formation of lithium dendrites, and improves the buffer effect, leading to increased coulombic efficiency and extended service life of the lithium-ion battery.
Implementation Method 1
amorphous micropores are formed throughout the first and/or second porous conductive sheet(s). They are formed on the surface of and/or within the first and/or second porous conductive sheet. When the porous conductive sheet is placed in contact with an active material, e.g., the negative electrode active material in a lithium-ion battery, such amorphous micropores can improve the adsorption of the active material
Implementation Method 2
when lithium ions enter into the negative electrode active material, the volume of the composite current collector may expand, and the amorphous micropores therein can better absorb the stress caused by expansion of the negative electrode active material
Implementation Method 3
the substrate sheet, which is made of a high molecular non-conductive material, can provide better support for the first porous conductive sheet and the second porous conductive sheet to prevent deformation thereof
Implementation Method 4
the substrate sheet, which is made of a high molecular non-conductive material, can provide better support for the first porous conductive sheet and the second porous conductive sheet to prevent deformation thereof, and can also insulate the active material
Data Source
AI summary
Disclosed herein is a composite current collector, a manufacturing method thereof, an electrode and a lithium-ion battery comprising the composite current collector. The composite current collector comprises: a first porous conductive sheet, a substrate sheet, and a second porous conductive sheet that are laminated in sequence, and the first porous conductive sheet and the second porous conductive sheet comprise amorphous micropores throughout the porous conductive sheets, the substrate sheet is made of a high molecular non-conductive material, and the first porous conductive sheet and the second porous conductive sheet are in conduction with each other in the electrode tab area.