Glassy Sulphide Solid Electrolyte Production With Fewer Inclusions
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Solution Overview
Problem
Existing methods for producing sulphide-based lithium-ion conducting solid electrolytes suffer from impurities and inclusions such as crystallized material, unreacted precursors, and gas bubbles, which compromise their isotropic conductivity and increase the risk of dendrite formation.
Innovation Solution
A method involving the melt-quenching of Li2S, boron, sulfur, and B2O3, optionally with LiX (where X represents F, Cl, Br, I, etc.), to produce glassy solids with reduced inclusions and improved thermal stability and ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional melt-quenching methods using B2S3 are used to produce sulphide-based solid electrolytes, then the production process is simple, but the resulting glass contains inclusions such as gas bubbles, crystallized zones, and unreacted precursors that compromise material quality
Solution Approach 1:
The patent changes the chemical composition parameters by replacing B2S3 with a combination of boron oxide (B2O3) and sulfur (S) in specific molar ratios. This parameter change fundamentally alters the melt chemistry and reaction pathways, eliminating the formation of unwanted inclusions while maintaining the glassy solid electrolyte structure and high ionic conductivity.
Solution Approach 2:
The patent creates a composite precursor system combining B2O3, S, and Li2S that reacts during melt-quenching to form the desired Li2S-B2S3 glassy phase. This composite approach ensures complete reaction and eliminates unreacted precursors and crystallized zones, producing a homogeneous glassy solid electrolyte with superior quality.
2Reliability
If glassy solid electrolyte materials are produced to achieve dense defect-free films, then isotropic conduction and dendrite prevention are improved, but the presence of any inclusions acts as nucleation agents that favor crystallization and compromise protective behavior
Solution Approach 1:
By adjusting the molar ratios of B2O3, S, and Li2S and controlling the melt-quenching parameters, the patent achieves complete reaction and forms a homogeneous glassy solid electrolyte. This precise parameter control eliminates inclusions that would act as nucleation sites, ensuring the material remains amorphous and isotropic, thereby maintaining protective behavior against dendrite formation.
3Reliability
If liquid electrolytes are used in lithium-ion batteries, then ionic conductivity is achieved, but inflammability and safety risks increase
Solution Approach 1:
The patent utilizes the phase transition from liquid to solid by producing a glassy solid electrolyte through melt-quenching. This solid state provides inherent safety by eliminating inflammability and leakage risks associated with liquid electrolytes, while the glassy amorphous structure maintains high ionic conductivity through its isotropic conduction pathways.
4Ease of manufacture
If B2S3 is used as the sole boron-sulfur source in melt-quenching, then the production process is straightforward, but gas bubbles and inclusions form in the resulting glass
Solution Approach 1:
The patent changes the precursor composition from using B2S3 to using B2O3 and S in specific molar ratios. This parameter change modifies the reaction chemistry during melt-quenching, preventing gas bubble formation and inclusion generation while maintaining process simplicity and producing high-purity glassy solid electrolyte.
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 results in glassy solids with minimal gas bubbles, high ionic conductivity (up to 2 mS/cm), low electronic conductivity (less than 1×10−9 mS/cm), and thermal stability (ΔTx > 100°C), enhancing the safety and performance of solid-state lithium-ion batteries.
Implementation Method 1
heat-treating the mixture prepared in step (ii) to obtain a melt
Implementation Method 2
quenching the melt obtained in step (iii) to obtain the solid material
Data Source
AI summary
The present invention relates to methods for the production of solid materials which are obtainable by melt-quenching mixtures comprising lithium sulphide and boron sulphide, thereby forming a glassy solid which is suitable for use as a lithium-ion conducting electrolyte. The present inventors have demonstrated that the method results in the production of sulphide based lithium-ion conducting solid electrolytes of improved quality, in particular having less inclusions of foreign material, such as gas bubbles.