Chloride Solid Electrolyte Composition for Reduction Resistance
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Solution Overview
Problem
Existing solid electrolytes, such as Li3YCl6, exhibit high ionic conductivity but lack stability, particularly in humid environments, and require improved resistance to reduction to enhance energy density in all-solid-state batteries.
Innovation Solution
A solid electrolyte composition comprising Li, Mα, Mβ, Mγ, and Cl, where Mα includes Zr or Hf, Mβ includes Ta or Nb, Mγ includes Gd, Yb, Dy, Er, or Sc, and A includes anions like OH-, AlO2-, SO42-, or TFSI-, formulated as Li6-(4+a-b)(1+c)(Mα(1-a-b)MβaMγb)1+cCl6·n(MδxAy), with specific valence relationships, to achieve high stability and resistance to reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chloride electrolytes such as Li3YCl6 are used, then high ionic conductivity at ambient temperature is achieved, but stability against humidity is poor and decomposition occurs
Solution Approach 1:
The patent employs composite material design by combining multiple cations (Mα from Zr/Hf, Mβ from Ta/Nb, Mγ from rare earth elements) with chloride anions to form a composite electrolyte material Li6-(4+a-b)(1+c)(Mα(1-a-b)MβaMγb)1+cCl6. This composite structure integrates the advantages of different elements: Mα provides structural stability, Mβ enhances ionic conductivity, and Mγ improves overall stability against humidity while maintaining high ionic conductivity, thereby resolving the contradiction between conductivity and humidity stability.
2Reliability
If solid electrolytes are improved for energy density, then resistance to reduction must be improved, but this increases device complexity
Solution Approach 1:
The patent applies parameter changes by systematically varying the compositional parameters (a, b, c) in the electrolyte formula Li6-(4+a-b)(1+c)(Mα(1-a-b)MβaMγb)1+cCl6 to optimize performance. By adjusting these parameters within specific ranges (0<a≤1, 0<b<1, 0<c≤1), the patent achieves improved resistance to reduction while controlling the complexity of the electrolyte composition. This allows tuning of the material properties to balance energy density and reduction resistance without excessive complexity.
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 proposed electrolyte composition enhances stability and resistance to reduction, allowing for higher energy density and improved safety in all-solid-state batteries.
Implementation Method 1
Li 3 YCl 6 exhibits high Li ionic conductivity at ambient temperature
Data Source
Figure 1
AI summary
A solid electrolyte contains Li, Mα, Mβ, Mγ, Cl, and A. Mα is at least one element selected from a group consisting of Zr and Hf. Mβ is at least one element selected from a group consisting of Ta and Nb. Mγ is at least one element selected from a group consisting of Gd, Yb, Dy, Er, Ho, Eu, and Sc. A is at least one type selected from a group consisting of OH-, AlO2-, SO3-, SO42-, SiO32-, SiO44-, Si2O76-, CO32- PO43- P2O74-, BO2-, BO33-, PO3-, NO3-, BF4-, PF6-, ClO4-, B(C2O4)2-, CH3COO-, TFSI-, and FSI-. This provides the solid electrolyte with excellent resistance to reduction.