Lithium Metal Anode Nitride Coating for Dendrite Suppression
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Solution Overview
Problem
Lithium-sulfur batteries using lithium metal as a negative electrode face instability due to high reactivity, leading to the formation of lithium dendrites, which causes internal short circuits and reduces battery capacity and cycle lifetime, limiting their commercial availability.
Innovation Solution
A method of manufacturing a lithium metal negative electrode by applying lithium nitride powder and forming a lithium nitride protective layer in the form of a powder bed of particles on the lithium metal surface through rolling, which suppresses lithium dendrite growth and improves lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte interface layer is formed on the lithium metal surface to suppress direct reaction with electrolyte, then stability of lithium metal is improved, but the layer collapses during charging/discharging causing lithium dendrite formation
Solution Approach 1:
The patent introduces lithium fluoride (LiF) as an intermediary protective layer between lithium metal and the electrolyte. This LiF layer serves as a mediator that prevents direct contact between lithium metal and electrolyte, suppressing dendrite formation while maintaining structural stability during battery cycling. The LiF layer is formed by applying lithium fluoride powder to the lithium metal surface before assembling the battery.
Solution Approach 2:
The patent modifies the surface properties of lithium metal by changing the chemical composition parameter - specifically by coating with lithium fluoride. This parameter change transforms the surface from reactive lithium metal to a stable LiF-coated surface, which has different mechanical and chemical properties that prevent layer collapse and dendrite formation during electrochemical cycling.
2Quantity of substance
If lithium metal is used as negative electrode active material to achieve high capacity and high energy density, then battery capacity and energy density are improved, but high chemical reactivity causes instability and dendrite formation
Solution Approach 1:
Lithium fluoride powder is applied as an intermediary protective coating on the lithium metal surface. This intermediary layer maintains the high capacity benefits of lithium metal while protecting it from harmful chemical reactions with the electrolyte, thereby improving chemical stability without sacrificing battery capacity.
3Reliability
If the solid electrolyte interface layer is formed by reaction between electrolyte and lithium metal, then passivation is achieved, but mechanical strength is weak causing layer collapse
Solution Approach 1:
The patent changes the material parameter of the protective layer from a reaction-formed SEI layer to a lithium fluoride-based protective layer. This parameter change results in a layer with superior mechanical strength that maintains its structural integrity during battery cycling, preventing collapse and subsequent dendrite formation.
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 method effectively enhances the capacity and lifetime of lithium-sulfur batteries by stabilizing the lithium metal negative electrode and improving lithium ion conductivity, making the batteries more suitable for commercial use.
Implementation Method 1
applying lithium nitride powder and forming a lithium nitride protective layer in the form of a powder bed of particles on the lithium metal surface through rolling
Data Source
Figure 1(a)~2
Figure 3~4
AI summary
The present invention relates to a method of manufacturing a lithium metal negative electrode, a lithium metal negative electrode manufactured thereby, and a lithium-sulfur battery including the same, more particularly, to a method of manufacturing a lithium metal negative electrode comprising the steps of (a) applying lithium nitride powder on at least one surface of a lithium metal layer including lithium metal; and (b) rolling the applied powder to form a lithium nitride protective layer of a powder bed on at least one surface of the lithium metal layer including lithium metal.