LGPS Sulfide Electrolyte Composition for Impurity-Controlled Ion Transport
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Solution Overview
Problem
Current sulfide solid electrolytes for solid-state batteries lack high ion conductivity, which is essential for improving battery performance.
Innovation Solution
A sulfide solid electrolyte with a LGPS-type crystal phase containing Li, P, and S, along with elements like Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, and Nb, is developed, where specific half-value width and impurity phase rate relationships are optimized through 31P-NMR measurements to enhance ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sulfide solid electrolytes are used, then the battery structure can be simplified with solid electrolyte, but the ion conductivity is insufficient for high performance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters (α values) of the Li4-αM1-αPαS4 solid electrolyte system. By varying α within specific ranges (0.55≤α≤0.76) and controlling the ratio of M1/M2 elements, the invention achieves optimal ion conductivity of 5.0 mS/cm or more at 25°C while maintaining structural stability and avoiding impurity phases.
Solution Approach 2:
The patent employs composite materials by combining multiple elements (Li, M1, M2, P, S) in a specific LGPS-type crystal structure. The composite sulfide solid electrolyte integrates different metallic elements (such as Li-Na-K-Ca-Mg for M1 and P-Sb-Si-Ge-Sn-B-Al-Ga-In-Ti-Zr-V-Nb for M2) to achieve synergistic effects that enhance ion conductivity while maintaining structural integrity.
2Reliability
If LGPS-type crystal phase is used, then high ion conductivity can be achieved, but impurity phases may form reducing performance
Solution Approach 1:
The patent uses parameter changes by defining specific compositional ranges (0.55≤α≤0.76) and stoichiometric ratios to prevent impurity phase formation. By controlling the α parameter and M1/M2 element ratios within these ranges, the invention ensures formation of pure LGPS-type crystal phase with characteristic XRD peaks and achieves ion conductivity of 5.0 mS/cm or more without performance-degrading impurities.
Data Source
Figure 1A~2
Figure 3~4
AI summary
Amain object of the present disclosure is to provide a sulfide solid electrolyte with high ion conductivity. The present disclosure achieves the object by providing a sulfide solid electrolyte including a LGPS-type crystal phase containing a Li element, an M element, a P element, and a S element, wherein: the M element is at least one kind or more of an element selected from Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb; and in a 31P-NMR measurement, when y (ppm) designates a half value width of a peak having an apex at a position of 77 ppm ± 1 ppm, and x (%) designates a rate of impurity phase measured, the sulfide solid electrolyte satisfies a below formula (1): y≤−0.0431x+4.28