Metallic Fabric Electrode with Protrusions for Flexible Battery Current Collectors
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Solution Overview
Problem
Current flexible lithium-ion batteries (LIBs) face challenges in mechanical stability and electrical conductivity, particularly when subjected to deformations like folding and twisting, due to the low fatigue strength of metals used in conventional current collectors, which limits their suitability for wearable electronic devices.
Innovation Solution
The development of an electrode comprising a metallic fabric with a nickel or copper coating and protrusions, where the active material is attached to these protrusions, enhancing both electrical conductivity and mechanical stability, achieved through electroless and electrochemical deposition processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thin aluminum or copper foils are used as current collectors in flexible LIBs, then flexibility is improved, but mechanical stability deteriorates due to low fatigue strength
Solution Approach 1:
The patent uses a composite structure consisting of a flexible substrate (polymer or metal foil) combined with a porous metallic coating layer (nickel, copper, or their alloys). This composite structure allows the current collector to maintain flexibility from the substrate while gaining enhanced mechanical stability and fatigue resistance from the porous metallic coating, resolving the contradiction between flexibility and mechanical strength.
Solution Approach 2:
The patent applies a porous metallic coating only on the surface of the flexible substrate rather than using a thick rigid material throughout. This local application of metallic material provides the necessary mechanical stability and electrical conductivity at the surface while preserving the flexibility of the underlying thin substrate, thus resolving the contradiction between flexibility and mechanical strength.
2Adaptability or versatility
If carbon nanomaterials are used as current collectors in flexible LIBs, then flexibility is improved, but electrical conductivity deteriorates due to high electrical resistance
Solution Approach 1:
The patent creates a composite structure with a flexible substrate covered by a porous metallic coating layer. The metallic coating (nickel, copper, or alloys) provides high electrical conductivity while the substrate maintains flexibility, thus resolving the contradiction between flexibility and electrical conductivity that plagues carbon-based current collectors.
Solution Approach 2:
The patent applies a thin porous metallic coating (1-10 μm) on the surface of the flexible substrate. This localized metallic layer provides the necessary electrical conductivity pathways without requiring thick rigid material, thus maintaining flexibility while improving electrical conductivity compared to bulk carbon materials.
3Strength
If the coating layer is made thicker to improve mechanical stability, then strength is improved, but electrical conductivity deteriorates due to increased resistance
Solution Approach 1:
The patent employs a porous metallic coating structure with controlled porosity (30-70%). The porous structure provides mechanical stability and structural integrity through the three-dimensional network of metal struts, while simultaneously maintaining electrical conductivity through continuous metallic pathways. The porosity allows the coating to be thin (1-10 μm) while still providing adequate mechanical support, thus resolving the contradiction between mechanical stability and electrical conductivity.
Solution Approach 2:
The composite structure of flexible substrate plus porous metallic coating allows optimization of coating thickness. The substrate provides mechanical support while the thin porous metallic layer provides electrical conductivity pathways, enabling the system to achieve both mechanical stability and electrical conductivity without requiring thick coatings that would increase 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
The metallic fabric-based electrodes demonstrate improved energy density, power density, and electrochemical stability under mechanical deformations, making them suitable for wearable and flexible LIBs with enhanced performance and durability.
Implementation Method 1
depositing nickel metal by an electroless deposition on one or more fibers to at least partially cover each of the one or more fibers with the layer
Implementation Method 2
depositing nickel metal by an electrodeposition on each layer to form the plurality of protrusions
Data Source
AI summary
An electrode for a battery, comprising an active material and a metallic fabric is disclosed. The metallic fabric comprises fibers being at least partially covered by a coating of nickel or copper, which comprises a layer and a plurality of protrusions protruding from the layer. The active material is attached on the protrusions. The metallic fabric provides a high electrical conductivity and a high mechanical stability, and demonstrates outstanding performance for the use as a current collector of battery.