Aluminum Anode Current Collectors with Conductive Protection Layer
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Solution Overview
Problem
Aluminum is not typically used as an anode current collector in lithium ion batteries due to its reactivity with lithium, leading to corrosion and degradation, which limits its application in electrochemical cells.
Innovation Solution
The use of an aluminum alloy layer with a conductive protection layer that prevents lithium atoms or ions from contacting the aluminum, thereby protecting it from corrosion and degradation, while maintaining electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum is used as an anode current collector, then weight and cost are reduced, but aluminum undergoes reactive alloying with lithium leading to corrosion and degradation
Solution Approach 1:
A conductive protection layer is introduced as an intermediary between the aluminum alloy layer and the lithium-containing environment. This protection layer prevents direct contact between lithium atoms/ions and the aluminum, blocking the harmful alloying reaction while maintaining electrical conductivity for current collection.
Solution Approach 2:
The current collector is designed as a composite structure consisting of an aluminum alloy layer combined with a conductive protection layer. This composite material approach allows the system to benefit from the low weight and cost of aluminum while the protection layer provides the necessary stability and resistance to lithium alloying.
2Reliability
If a protection layer is added to prevent lithium alloying, then reliability is improved, but device complexity increases
Solution Approach 1:
The conductive protection layer is implemented as a thin film coating on the aluminum alloy layer. This thin film approach provides the necessary protection against lithium alloying while minimizing the addition of complexity and maintaining a relatively simple overall structure that is easy to manufacture.
3Object-affected harmful factors
If the conductive protection layer prevents lithium transmission, then corrosion is prevented, but electrical conductivity may be compromised
Solution Approach 1:
The conductive protection layer is specifically selected and engineered to have appropriate electrical conductivity parameters. By controlling the material composition and properties of the protection layer, it achieves a balance where it is sufficiently impermeable to lithium atoms/ions while maintaining adequate electrical conductivity for current collection functionality.
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 approach allows for the stable use of aluminum as an anode current collector, enhancing the cyclability and reducing weight and cost in lithium ion batteries by preventing alloying and corrosion, with the conductive protection layer ensuring the aluminum alloy layer remains conductive and protected.
Implementation Method 1
The conductive protection layer may prevent transmission of lithium atoms or lithium ions to the aluminum alloy layer
Implementation Method 2
The conductive protection layer may allow transmission of electrons from external to the conductive protection layer to the aluminum alloy layer
Data Source
AI summary
Described are substrates including a layer of an aluminum alloy with a conductive coating, also referred to as a protective overlayer. The conductive coating can prevent certain material from coming into contact with the aluminum alloy layer while allowing transmission of electrons to the aluminum alloy. The substrates may be used, for example, in electronics applications, such as current collectors or electrodes for batteries, electrochemical cells, capacitors, supercapacitors, or the like.