Nitrogen Argyrodite Solid Electrolyte for High-Voltage Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithium-ion batteries using liquid electrolytes pose safety risks due to flammable organic solvents, and sulfide-based solid electrolytes have weak stability at high voltages, necessitating an improved solid electrolyte for enhanced safety and performance.
Innovation Solution
A solid electrolyte with a nitrogen-containing compound having an argyrodite crystal structure, specifically represented by Formula (Li1-aMa)7-d+xPS6-d-x+kNxXd, is developed, which includes a mixture of lithium, sulfur, phosphorus, and nitrogen precursors, heat-treated at temperatures above 300°C to achieve improved ion conductivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolyte is used, then ion conductivity is improved, but stability towards oxidation at high voltage deteriorates
Solution Approach 1:
The patent applies composite materials by combining multiple elements (Li, P, S, Ge, and halogens) to form a complex argyrodite structure. This composite approach allows the electrolyte to achieve both high ion conductivity and improved oxidation stability at high voltages, resolving the contradiction between these two properties that plagues simpler sulfide-based electrolytes.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the composition ratios of Li, P, S, Ge, and halogen elements in the argyrodite structure. By optimizing these compositional parameters, the electrolyte achieves enhanced oxidation stability while maintaining high ion conductivity, thus resolving the contradiction between these two critical properties.
2Ease of manufacture
If liquid electrolyte is used, then ease of manufacture is improved, but safety deteriorates due to flammable organic solvent
Solution Approach 1:
The patent applies parameter changes by transitioning from liquid to solid state electrolyte, fundamentally changing the physical state parameter. This solidification eliminates the flammability issue while the argyrodite crystal structure maintains good ion conductivity, thus improving safety without severely compromising manufacturability.
Solution Approach 2:
The patent uses composite materials by creating a complex argyrodite structure with multiple elements (Li, P, S, Ge, halogens) that combines the advantages of solid electrolytes (safety) with high ion conductivity. This composite approach makes solid electrolytes more viable for practical applications compared to simple solid electrolytes.
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 nitrogen-containing solid electrolyte exhibits stabilized interfaces, increased ion conductivity, and enhanced high-voltage stability, leading to improved discharge capacity and cycle characteristics in electrochemical cells, making them safer and more efficient.
Implementation Method 1
heat-treating the solid electrolyte precursor at a temperature equal to or greater than about 300° C. to prepare the solid electrolyte including the compound of Formula 1
Implementation Method 2
a solid electrolyte with a nitrogen-containing compound having an argyrodite crystal structure
Data Source
AI summary
A solid electrolyte including a compound represented by Formula 1:(Li1-aMa)7-d+xPS6-d-x+kNxXd Formula 1wherein, in Formula 1,M is Na, K, Ca, Fe, Mg, Ag, Cu, Zr, Zn, or a combination thereof;X is Cl, Br, F, I, a pseudohalogen, or a combination thereof; and0<x<1, 0≤a<1, 0<d≤1.8, and 0≤k<1, andwherein the compound has an argyrodite crystal structure.