Diazonium-Protected Lithium Metal Electrode 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, which can cause cell short circuits and safety problems, and existing methods for forming protective layers are complex and economically inefficient.
Innovation Solution
A negative electrode with a diazonium ion-containing protective layer is formed by reacting a nitrite compound and an amine compound on a lithium metal thin film, providing a thin, 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 and mass production is difficult
Solution Approach 1:
The patent replaces the mechanical/physical vapor deposition process (ALD/MLD requiring vacuum equipment) with a chemical solution-based diazonium ion formation method. This substitution eliminates the need for expensive vacuum equipment and complex process control, enabling simple dip-coating or spray-coating operations that are economically viable for mass production while still achieving uniform nanoscale protective layers
Solution Approach 2:
The patent changes the fundamental parameter of the deposition process from physical vapor phase (requiring vacuum) to chemical solution phase (ambient conditions). By using diazonium ion chemistry in liquid solution, the process achieves comparable film quality to ALD/MLD but under vastly simplified conditions that are suitable for industrial manufacturing
2Use of energy by moving object
If lithium metal is used as negative electrode material, then high energy density and capacity are achieved, but large volume change occurs during charge and discharge
Solution Approach 1:
The patent applies a protective layer formed by diazonium ions on the lithium metal surface before the battery operates. This pre-formed protective layer acts as a cushioning barrier that accommodates and buffers the large volume changes of lithium metal during charge-discharge cycles, preventing direct contact between the expanding/contracting lithium and the electrolyte, thereby maintaining structural integrity and preventing dendrite formation
3Use of energy by moving object
If lithium metal is used as negative electrode material, then high energy density is achieved, but lithium dendrites grow and penetrate separator causing short circuit
Solution Approach 1:
The patent applies preliminary anti-action by forming a diazonium ion protective layer on the lithium metal surface before dendrite growth can occur. This protective layer creates a stable interface that prevents the irregular lithium deposition that leads to dendrite formation, thereby preemptively eliminating the safety hazard while preserving the high energy density benefits of lithium metal
4Manufacturing precision
If protective layer is formed by ALD or MLD, then uniform nanoscale thin layer is achieved, but additional expensive equipment and high vacuum are required
Solution Approach 1:
The patent substitutes the complex mechanical vacuum deposition system with a simple chemical solution processing method. The diazonium ion formation occurs in liquid solution at ambient conditions, eliminating all vacuum equipment, heating racks, and complex process control systems required by ALD/MLD, while achieving comparable nanoscale film uniformity
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 protective layer effectively prevents dendrite growth and improves the performance and lifespan 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
Implementation Method 2
reacting a nitrite compound and an amine compound on a 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.