Haloboro-Oxysulfide Solid Electrolytes for Stable Li-Ion Conduction
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Solution Overview
Problem
Existing solid electrolytes for lithium batteries face challenges in achieving high lithium ion conductivity while maintaining chemical and electrochemical stability, particularly due to the air and moisture sensitivity of sulfide-based materials.
Innovation Solution
A solid material with a composition defined by the general formula Li2x+zB2yMaOb*aSx+3yXz, which combines oxides and sulfides, exhibits favorable lithium ion conductivity and stability by incorporating halides or pseudohalides, forming an amorphous haloboro-oxysulfide structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide-based solid electrolyte materials are used, then high lithium ion conductivity is achieved, but air stability and moisture resistance deteriorate
Solution Approach 1:
The patent employs composite materials by combining sulfide components (Li2S, B2S3) with oxide components (SiO2, P2O5, GeO2, As2O3, Sb2O3) to create haloboro-oxysulfide glassy solid electrolytes. This composite approach allows the material to inherit high ionic conductivity from sulfides while gaining air and moisture stability from oxides, directly resolving the contradiction between conductivity and stability.
Solution Approach 2:
The patent modifies the chemical composition parameters by incorporating halide salts (LiCl, LiBr, LiI) and pseudohalide salts into the glassy matrix, changing the stoichiometric ratios of Li2S, B2S3, and oxide components. This parameter optimization enables achieving high ionic conductivity (≥10^-4 S/cm at 25°C) while maintaining stability against air and moisture through controlled composition within specified ranges.
2Object-affected harmful factors
If oxide-based solid electrolyte materials are used, then chemical and electrochemical stability is improved, but lithium ion conductivity deteriorates
Solution Approach 1:
The patent creates a composite glassy system where oxide network formers (SiO2, P2O5, GeO2, As2O3, Sb2O3) provide structural stability and chemical resistance, while sulfide components (Li2S, B2S3) and halide additives maintain high lithium ion conductivity. The synergistic combination resolves the contradiction by allowing oxides to form a stable framework that supports ion transport pathways.
Solution Approach 2:
The patent applies local quality by creating distinct functional regions within the glassy matrix: oxide-rich domains provide structural stability and chemical resistance, while sulfide-halide rich regions provide ion conduction pathways. This spatial differentiation of properties allows the material to simultaneously exhibit both high stability and high conductivity.
3Reliability
If glassy solid electrolyte materials are used, then isotropic conduction and dendrite prevention are achieved, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes the phase transition from crystalline to amorphous state through melt-quenching. By melting the precursor mixture and rapidly cooling it, the material forms a glassy amorphous structure without crystalline grain boundaries. This phase transition approach enables isotropic conduction and dendrite prevention while using a relatively simple one-step manufacturing process.
Solution Approach 2:
The patent performs preliminary mixing of all precursor components (Li2S, B2S3, SiO2, P2O5, GeO2, As2O3, Sb2O3, and halide salts) in precise stoichiometric ratios before melting. This preliminary preparation ensures homogeneous composition, which facilitates uniform glass formation and consistent ionic conductivity throughout the electrolyte, simplifying the overall manufacturing process.
Data Source
AI summary
Described are a solid material which has ionic conductivity for lithium ions, a process for preparing the solid material, a use of the solid material as a solid electrolyte for an electrochemical cell, a solid structure selected from the group consisting of a cathode, an anode and a separator for an electrochemical cell, and an electrochemical cell including the solid structure.