Lithium Metal Negative Electrode Protective Layer Dendrite Suppression
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Solution Overview
Problem
Lithium metal negative electrodes in secondary batteries face issues with dendrite formation, reactivity with electrolytes, and instability due to high reactivity with moisture, leading to non-uniform current distribution, internal short circuits, and poor handling properties, which hinder the development of high energy density and long-life lithium secondary batteries.
Innovation Solution
A sulfur dioxide-based sodium molten salt is used to form a protective layer on the surface of the lithium metal current collector, suppressing dendrite growth and enhancing the battery's energy density, life, and stability by creating a film containing Na, Cl, or S through immersion in a solution like NaAlCl4-2SO2 or NaGaCl4-2SO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a lithium metal negative electrode is used to achieve high energy density, then the energy density increases significantly, but dendrite formation occurs during charging and discharging
Solution Approach 1:
A protective layer comprising Li2SiO3, Li2CO3, and LiF is introduced as an intermediary between the lithium metal negative electrode and the electrolyte solution. This protective layer acts as a mediator that prevents direct contact and harmful reactions while allowing ionic transport, thereby suppressing dendrite formation without compromising the high energy density benefits of lithium metal
Solution Approach 2:
The protective layer is composed of a composite structure containing multiple compounds (Li2SiO3, LiCO3, and LiF) in specific ratios. This composite material provides synergistic effects: Li2SiO3 offers mechanical stability, Li2CO3 provides chemical stability, and LiF enhances ionic conductivity, collectively suppressing dendrite formation while maintaining high energy density
2Use of energy by moving object
If a lithium metal negative electrode is used to achieve high energy density, then the energy density increases, but the battery stability deteriorates due to reactivity with moisture
Solution Approach 1:
The protective layer serves as a stable intermediary barrier between the highly reactive lithium metal and moisture in the electrolyte solution. This layer prevents direct reaction between lithium and water, eliminating the generation of heat and gas that would compromise battery stability, while preserving the high energy density characteristics of lithium metal
Solution Approach 2:
The protective layer creates an inert environment around the lithium metal surface, preventing contact with reactive species in the electrolyte solution and moisture. This inert barrier maintains battery stability by eliminating parasitic reactions while allowing the lithium metal to function at its full energy density potential
3Ease of manufacture
If a lithium metal negative electrode is used without surface treatment, then the manufacturing process is simple, but the handling property deteriorates due to high reactivity
Solution Approach 1:
The protective layer is formed preliminarily on the lithium metal surface before battery assembly through a simple one-step immersion process. This preliminary action of surface treatment enhances handling properties and stability without adding complex manufacturing steps, as the protective layer forms automatically during a single immersion in the electrolyte solution
4Reliability
If a protective layer is formed on the lithium metal surface to suppress dendrite formation, then the reliability improves, but the device complexity increases
Solution Approach 1:
The protective layer is formed through a self-service mechanism where the lithium metal surface automatically forms the protective coating during a simple immersion process. The specific composition (Li2SiO3, Li2CO3, and LiF in controlled ratios) is achieved through self-organization during the immersion, eliminating the need for complex multi-step coating equipment or procedures while ensuring reliable dendrite suppression
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 protective layer effectively prevents dendrite formation, ensuring high energy density, long-life characteristics, and stability in lithium secondary batteries by minimizing reactivity and improving handling properties, thus addressing key challenges in lithium metal electrode technology.
Implementation Method 1
forming a protective layer on the surface of a current collector by immersing the current collector in the sulfur dioxide-based sodium molten salt
Data Source
AI summary
The present invention relates to a negative electrode for a lithium secondary battery that can ensure a high energy density, a long-life characteristic, and stability by forming a film on a negative electrode for a lithium secondary battery and thus suppressing dendrites during electrodeposition, a method of manufacturing the same, and a lithium secondary battery using the same. The method of manufacturing the negative electrode for a lithium secondary battery according to the present invention includes preparing a sulfur dioxide-based sodium molten salt and forming a protective layer on the surface of a current collector by immersing the current collector in the sulfur dioxide-based sodium molten salt.