Multi-Layer Protective Anode for Lithium Metal Batteries
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Solution Overview
Problem
Lithium secondary batteries using lithium metal as a negative electrode face issues with dendrite growth, leading to cell volume expansion, battery performance decline, and safety risks such as explosion and fire, due to non-uniform electron density and the formation of lithium dendrites on the electrode surface.
Innovation Solution
A negative electrode with a multilayer-structured protective layer comprising a composite material of carbon nanotube-ion conductive polymer and carbon nanotube-electrically conductive polymer, which are alternately laminated on the lithium metal layer to prevent dendrite growth and maintain battery stability during charge and discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as a negative electrode to achieve high capacity, then energy density is improved, but lithium dendrite growth occurs causing safety risks and performance decline
Solution Approach 1:
The protective layer is divided into multiple segments with different functions: a first protective layer containing ion-conductive polymer for ion transport, a second protective layer containing electrically conductive polymer for electron conduction, and a third protective layer containing both types of polymers for combined functionality. This segmentation allows each layer to address specific aspects of the dendrite problem while maintaining overall battery performance.
Solution Approach 2:
The protective layer uses composite materials combining ion-conductive polymers (such as polyethylene oxide, polyethylene glycol) with electrically conductive polymers (such as polyaniline, polythiophene). This composite structure provides both ion conductivity and electrical conductivity, creating a balanced protective interface that prevents dendrite formation while maintaining high lithium capacity.
2Reliability
If a protective layer is introduced to prevent dendrite growth, then battery safety is improved, but battery performance may decline due to additional resistance
Solution Approach 1:
The protective layer is designed with controlled thickness parameters (each layer 1-10 μm) and optimized compositional ratios of ion-conductive to electrically conductive polymers. By carefully adjusting these parameters, the layer provides sufficient protection against dendrites while minimizing resistance to ion and electron transport, thus maintaining battery performance.
Solution Approach 2:
Different regions of the protective layer have different properties: the first layer near the lithium metal surface focuses on ion conduction, the second layer focuses on electrical conduction, and the third layer provides both functions. This local differentiation allows each region to optimize its function, preventing dendrites while maintaining overall battery performance.
3Reliability
If multiple protective layers are used to suppress dendrite growth, then dendrite prevention is improved, but device complexity increases
Solution Approach 1:
The protective layer is divided into multiple segments with different functions: a first protective layer containing ion-conductive polymer for ion transport, a second protective layer containing electrically conductive polymer for electron conduction, and a third protective layer containing both types of polymers for combined functionality. This segmentation allows each layer to address specific aspects of the dendrite problem while maintaining overall battery performance.
Solution Approach 2:
The protective layer uses composite materials combining ion-conductive polymers (such as polyethylene oxide, polyethylene glycol) with electrically conductive polymers (such as polyaniline, polythiophene). This composite structure provides both ion conductivity and electrical conductivity, creating a balanced protective interface that prevents dendrite formation while maintaining high lithium 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 multi-protective layer effectively suppresses lithium dendrite growth, prevents overpotential, and enhances battery performance by maintaining stability and preventing battery performance decline, making it suitable for various electronic devices and energy storage applications.
Implementation Method 1
a first protective layer including a composite material of carbon nanotube-ion conductive polymer
Implementation Method 2
a second protective layer including a composite material of carbon nanotube-electrically conductive polymer
Implementation Method 3
a composite material of carbon nanotube-ion conductive polymer; a composite material of carbon nanotube-electrically conductive polymer
Data Source
Figure 1~3
Figure 4(a)~5(h)
Figure 6(i)~7(o)
AI summary
The present invention relates to a negative electrode including a multi-protective layer and a lithium secondary battery including the same, and the multi-protective layer prevents lithium dendrite growth on a surface of the electrode, and does not cause overpotential during charge and discharge since the protective layer itself does not function as a resistive layer, and therefore, is capable of preventing battery performance decline and securing stability when operating a battery.