Diazonium Protective Layer on Lithium Metal Anodes for Dendrite Control
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Solution Overview
Problem
Lithium metal secondary batteries face issues with large volume changes during charging and discharging, leading to the growth of acicular dendrites that can cause short circuits and safety problems, and existing methods for forming protective layers are complex and economically inefficient.
Innovation Solution
A diazonium ion-containing negative electrode protective layer is formed by reacting a nitrite compound and an amine compound on a lithium metal thin film, providing a nanoscale, uniform layer that suppresses dendrite growth and irreversible reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomic layer deposition method or molecular layer deposition method is used to form negative electrode protective layer, then uniform nanoscale thin protective layer can be formed, but economic efficiency is greatly degraded due to high vacuum formation and expensive equipment
Solution Approach 1:
The patent replaces the mechanical vacuum-based deposition system (ALD/MLD) with a chemical solution-based diazonium ion formation method. This substitution eliminates the need for expensive vacuum equipment while achieving comparable protective layer quality through chemical reactions in solution phase.
Solution Approach 2:
The invention uses inexpensive chemical reagents (diazonium salts, nitrite compounds, amine compounds) that can be easily disposed of after use, replacing expensive and reusable vacuum deposition equipment. This approach significantly reduces capital investment and operational costs.
2Manufacturing precision
If atomic layer deposition method is used to form negative electrode protective layer, then uniform nanoscale thin protective layer can be formed, but overall process is complicated and deposition rate is very slow
Solution Approach 1:
The patent replaces the slow, step-by-step vacuum deposition process with a rapid chemical reaction in solution. The diazonium ion formation and subsequent reduction occur quickly in liquid phase, dramatically increasing deposition rate and simplifying the overall process flow.
Solution Approach 2:
The invention changes the physical state parameter from gas phase (vacuum deposition) to liquid phase (solution-based chemistry). This parameter change enables faster reaction kinetics and simpler process equipment while maintaining the desired nanoscale protective layer quality.
3Quantity of substance
If lithium metal is used as negative electrode material, then high energy density and capacity can be achieved, but large volume change occurs during charge and discharge process
Solution Approach 1:
The patent applies a protective layer formation method that creates a stable interface before volume changes occur. The diazonium-based protective layer acts as a cushioning barrier that accommodates lithium's volume expansion and contraction during cycling, preventing structural degradation and maintaining electrode integrity.
4Quantity of substance
If lithium metal is used as negative electrode material, then high energy density and capacity can be achieved, but lithium grows into acicular shape to form lithium dendrites
Solution Approach 1:
The protective layer formed by diazonium ion chemistry serves as a pre-established cushioning barrier that prevents lithium from growing into dendritic structures. This layer provides a uniform interface that guides lithium deposition in a planar manner, eliminating the harmful acicular growth before it can occur.
Solution Approach 2:
The diazonium-based protective layer acts as an intermediary between the lithium metal and the electrolyte. This intermediate layer mediates the lithium deposition process, providing a controlled interface that prevents direct contact and uncontrolled dendrite formation while allowing ionic transport.
5Quantity of substance
If lithium metal is used as negative electrode material, then high energy density and capacity can be achieved, but reactivity with electrolyte solution is high causing irreversible reactions
Solution Approach 1:
The diazonium-based protective layer serves as an intermediary barrier between lithium metal and the electrolyte solution. This intermediate layer reduces direct reactivity, preventing irreversible side reactions while maintaining ionic conductivity for battery operation. The layer acts as a protective interface that preserves lithium's high capacity benefits while eliminating its high reactivity drawbacks.
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 diazonium ion-containing layer effectively prevents dendrite growth and improves the performance and lifetime of lithium metal secondary batteries, enabling mass production with a simplified process comparable to atomic layer deposition methods.
Implementation Method 1
a negative electrode protective layer including a diazonium ion chemically bonded to the lithium metal thin film
Data Source
Figure 1
AI summary
The present disclosure relates to a negative electrode for a secondary battery, including a negative electrode protective layer which can be formed by a more simplified method and can effectively suppress the growth of acicular dendrites generatedin the negative electrode of a lithium metal secondary battery, a method for manufacturing the same, and a lithium metal secondary battery comprising the same. The negative electrode for secondary battery includes a negative electrode current collector; a lithium metal (Li-metal) thin film formed on the negative electrode current collector; and a negative electrode protective layer including a diazonium ion chemically bonded to the lithium metal thin film.