Sulfide Solid Electrolyte Nitrogen Doping Phase Stability
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Solution Overview
Problem
The Li2S—P2S5—LiI—LiBr based sulfide solid electrolyte has limitations in increasing lithium ion conductivity, with a low temperature for high ion conduction phase formation and a narrow temperature range, requiring strict temperature control in the heating treatment.
Innovation Solution
Incorporating nitrogen (N) as a constituent element in the sulfide solid electrolyte, specifically in the form of Li3N, to improve lithium ion conductivity and broaden the temperature range for high ion conduction phase formation, allowing for a more versatile heating treatment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li2S-P2S5-LiI-LiBr based sulfide solid electrolyte is used, then lithium ion conductivity is improved, but the temperature range for high ion conduction phase is narrow and strict temperature control is required
Solution Approach 1:
The patent changes the compositional parameters of the sulfide solid electrolyte by adding nitrogen-containing compounds (Li3N, Li2SiO3) to the Li2S-P2S5-LiI-LiBr system. This compositional modification shifts the phase transition temperature to higher values and broadens the temperature range where the high ion conduction phase exists, thereby improving adaptability while maintaining high lithium ion conductivity of at least 5.2 mS/cm
Solution Approach 2:
The patent creates a composite sulfide solid electrolyte system by combining multiple components: Li2S, P2S5, LiI, LiBr, and nitrogen-containing compounds (Li3N, Li2SiO3). This composite material approach enables the system to achieve both high lithium ion conductivity and an expanded stable temperature range, resolving the contradiction between conductivity performance and temperature adaptability
2Reliability
If strict temperature control is implemented during heating treatment, then high lithium ion conductivity is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
By modifying the compositional parameters to include nitrogen-containing compounds, the patent shifts the phase transition characteristics to occur at higher temperatures with a broader stable range. This parameter change reduces the stringency of temperature control requirements during heating treatment, simplifying the heating apparatus design and manufacturing process while still achieving high lithium ion conductivity of at least 5.2 mS/cm
3Adaptability or versatility
If Li3N is added to broaden temperature range, then adaptability improves, but manufacturing precision requirements increase due to specific composition ratios
Solution Approach 1:
The patent establishes specific compositional parameter ranges: Li3N content of 0.01-5 wt% and Li2SiO3 content of 0.01-5 wt% in the Li2S-P2S5-LiI-LiBr system. These defined parameter ranges provide clear manufacturing guidelines that balance the need for broadened temperature adaptability with practical manufacturing precision requirements, making the composition control achievable in industrial production
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 inclusion of N in the sulfide solid electrolyte composition enhances lithium ion conductivity to at least 5.2 mS/cm, stabilizes the high ion conduction phase at higher temperatures, and reduces the need for strict temperature control during production, resulting in a more robust and efficient sulfide solid electrolyte.
Implementation Method 1
Li3N works to increase the lithium amount in a sulfide solid electrolyte
Implementation Method 2
N in Li3N is discharged outside the system as N2
Implementation Method 3
amorphizing a raw material composition that contains Li2S, P2S5, LiI, LiBr, and Li3N to form a glass
Implementation Method 4
carrying out a heating treatment to the glass to crystallize the glass
Data Source
AI summary
Disclosed is a sulfide solid electrolyte of high robustness in its production step and of high lithium ion conductivity, the sulfide solid electrolyte including Li, P, S, Br, I, and N as its constituent elements.