Cold Plasma Protective Layer for Stable Alkali Metal Anodes
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Solution Overview
Problem
Existing methods for forming protective layers on alkali metal and alkaline earth metal anodes in batteries face challenges such as complexity, contamination risks, difficulty in controlling layer uniformity, and instability, leading to issues like dendrite formation and reduced battery performance.
Innovation Solution
A method involving a cold plasma process is used to form a protective layer on alkali metal and alkaline earth metal surfaces by exposing the substrate to reactive precursors generated by a cold plasma, which creates a halide-containing layer that enhances stability and interface performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is formed on alkali metal anode surface, then corrosion resistance and interface stability are improved, but dendrite formation and layer uniformity control become more difficult
Solution Approach 1:
The patent changes the chemical composition parameters of the protective layer by incorporating specific ratios of LiF, Li2SiO3, and other inorganic compounds. This compositional optimization prevents dendrite formation while maintaining interface stability, resolving the contradiction between protection and uniformity control.
Solution Approach 2:
The protective layer is designed as a composite material containing multiple inorganic compounds (LiF, Li2SiO3, Li2CO3, etc.) in specific proportions. This composite structure provides both corrosion resistance and dendrite suppression, simultaneously achieving reliability improvement without increasing device complexity.
2Ease of manufacture
If wet chemical methods are used to deposit protective layer, then deposition process is simplified, but layer purity and uniformity are reduced
Solution Approach 1:
The patent replaces wet chemical deposition methods with a dry coating process followed by thermal treatment. This substitution eliminates solvent-related contamination and improves layer uniformity while maintaining manufacturing simplicity, resolving the contradiction between ease of manufacture and manufacturing precision.
Solution Approach 2:
The patent optimizes thermal processing parameters (temperature, time, atmosphere) to achieve uniform layer formation from the coated precursor. This parameter optimization ensures high layer uniformity and purity while keeping the overall process simple, addressing both ease of manufacture and manufacturing precision requirements.
3Reliability
If SEI layer is allowed to form naturally, then metal ion conductivity is maintained, but reaction mitigation and cell capacity are reduced
Solution Approach 1:
The patent applies a protective layer before the natural SEI layer forms during battery operation. This preliminary action creates a controlled interface that maintains metal ion conductivity while preventing harmful side reactions, thereby preserving cell capacity. The protective layer acts as a pre-formed barrier that guides subsequent SEI formation.
Solution Approach 2:
The patent modifies the interfacial composition parameters by introducing specific inorganic compounds (LiF, Li2SiO3) that have optimal conductivity and stability properties. This compositional change allows the protective layer to maintain metal ion conductivity while reducing parasitic reactions, thus preserving cell capacity.
4Productivity
If repeated charging and discharging is performed, then battery capacity is utilized, but non-uniform metal dissolution and dendrite formation increase
Solution Approach 1:
The patent applies a protective layer before cycling begins, which acts as a cushioning barrier against non-uniform metal dissolution and dendrite formation during repeated charging and discharging. This pre-formed protective interface absorbs mechanical and chemical stresses, maintaining anode surface uniformity throughout battery cycling.
Solution Approach 2:
The composite protective layer containing multiple inorganic compounds provides enhanced mechanical strength and chemical stability during cycling. This composite structure resists non-uniform dissolution and dendrite formation, maintaining anode surface uniformity even after repeated charging and discharging cycles.
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 allows for better control over the protective layer's formation, reduces unwanted by-products, and improves battery performance by providing a stable interface and uniform electrical field, enhancing long-term stability and charging efficiency.
Implementation Method 1
providing a cold plasma in the process chamber; introducing a precursor in the cold plasma to create reactive precursors in the cold plasma
Implementation Method 2
exposing at least a part of the surface of the alkali metal-containing substrate to the reactive precursors such as to form a protective layer on the substrate
Data Source
Figure 1a~1b
Figure 2~4d
Figure 5~6
AI summary
The present invention relates to a method for applying a protective layer to a surface of a substrate, the surface comprising a metallic element or an alloy thereof, in particular wherein the metallic element is an alkali metal or an alkaline earth metal. The present invention is further related to an article comprising such a substrate and a protective layer arranged on or covering at least part of the substrate. The invention is further related to an electrode comprising the article, in particular an anode, and to a battery (cell) comprising the electrode.