Composite Current Collector Coating for Corrosion-Resistant Cathodes
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Solution Overview
Problem
Current lithium-ion battery technology faces challenges with corrosion of current collectors due to alkaline reactions with nickel-containing cathode active materials in water-based slurries, and high interfacial resistance between electrode layers and current collectors, leading to poor electrochemical performance and irreversible capacity loss.
Innovation Solution
A modified current collector is introduced, comprising a substrate with a conductive layer that includes a conductive material, a metal compound, and a binder material. The conductive layer acts as a physical barrier to prevent corrosion and reduces interfacial resistance, while the metal compound compensates for metal ion loss during initial charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If water-based slurry is used to manufacture lithium-ion batteries, then manufacturing cost is reduced and environmental friendliness is improved, but corrosion of current collector occurs due to alkaline reaction with nickel-containing cathode active materials
Solution Approach 1:
A conductive layer is introduced as an intermediary between the nickel-containing cathode active material and the current collector. This conductive layer acts as a physical barrier that prevents direct contact between the alkaline slurry and the current collector, thereby eliminating corrosion while maintaining the benefits of water-based manufacturing
Solution Approach 2:
The current collector is modified by coating it with a composite conductive layer containing conductive material, metal compound, and binder material. This composite structure provides both corrosion protection and electrical conductivity, resolving the contradiction between using water-based slurries and protecting the current collector
2Device complexity
If conventional current collector is used, then device complexity is low, but interfacial resistance between electrode layer and current collector is high, leading to poor electrochemical performance
Solution Approach 1:
The current collector is transformed from a simple metal substrate to a composite structure with a conductive layer containing conductive material, metal compound, and binder material. This composite structure reduces interfacial resistance and improves electron transport, thereby enhancing electrochemical performance
Solution Approach 2:
The conductive layer is applied locally on the surface of the current collector where it contacts the electrode layer. This localized modification improves interfacial properties without changing the bulk properties of the current collector, maintaining simplicity while enhancing performance
3Quantity of substance
If nickel-containing cathode active materials are used, then specific capacity is high, but irreversible capacity loss occurs due to metal ion loss during initial charging
Solution Approach 1:
The metal compound in the conductive layer serves as a self-service reservoir that releases metal ions during initial charging to compensate for metal ion loss from the nickel-containing cathode material. This self-compensation mechanism reduces irreversible capacity loss while maintaining high specific capacity
Solution Approach 2:
The conductive layer containing metal compound is prepared in advance on the current collector surface. This pre-prepared layer acts as a cushioning reservoir that anticipates and compensates for metal ion loss during the first charging cycle, protecting the overall battery capacity
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 modified current collector enhances the electrochemical performance of lithium-ion batteries by preventing corrosion, reducing interfacial resistance, and minimizing irreversible capacity loss, thereby improving the overall efficiency and stability of the batteries.
Implementation Method 1
the conductive layer acts as a physical barrier to prevent corrosion
Implementation Method 2
the metal compound compensates for metal ion loss during initial charging
Implementation Method 3
reduces interfacial resistance
Data Source
AI summary
A modified current collector for a secondary battery is disclosed herein, comprising a substrate and a conductive layer applied on one side or both sides of the substrate, wherein the conductive layer comprises a conductive material, a binder material comprising a polymer, and a metal compound, and may additionally comprise a particulate material. Also provided herein is a cathode for a secondary battery, comprising the modified current collector and an electrode layer, wherein the electrode layer is located on the surface of the conductive layer. The presence of the conductive layer inhibits corrosion of the substrate and reduces interfacial resistance between the electrode layer and the substrate. In addition, the metal compound in the conductive layer reduces irreversible capacity loss due to SEI formation during initial charging of the battery. Consequently, batteries comprising the modified current collector exhibit exceptional electrochemical performance.