Solid Electrolyte Suppressing Hydrogen Sulfide in All Solid-State Lithium Batteries
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Solution Overview
Problem
Existing all solid-state lithium secondary batteries face the challenge of hydrogen sulfide generation, which cannot be effectively prevented by existing safety mechanisms, leading to potential leakage.
Innovation Solution
A solid electrolyte material represented by Li2S-MIaSb-MIIxOy is developed, where MI is selected from P, Si, Ge, B, or Al, and MII from Fe, Zn, or Bi, with specific stoichiometric ratios, incorporating oxides that stabilize sulfur and improve conductivity, thereby suppressing hydrogen sulfide generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a solid electrolyte material containing sulfur (Li2S-P2S5) is used to simplify the safety mechanism, then the battery structure is simplified and safety mechanism is reduced, but hydrogen sulfide is generated when the material contacts water, creating a new safety hazard
Solution Approach 1:
The patent converts the harmful sulfur component into a beneficial form by replacing P2S5 with metal sulfides (FeS2, ZnS, Bi2S3) that have lower reactivity with water. The sulfur is retained for maintaining ionic conductivity but is now in a chemically more stable form that does not readily generate hydrogen sulfide when contacting moisture, thus converting the harmful sulfur into a beneficial stable component.
Solution Approach 2:
The patent changes the chemical composition parameters of the solid electrolyte material by introducing metal sulfides with different reactivity characteristics. Specifically, it uses FeS2, ZnS, or Bi2S3 instead of P2S5, altering the chemical stability parameter while maintaining the necessary ionic conductivity for battery operation.
2Reliability
If the solid electrolyte material composition is optimized to suppress hydrogen sulfide generation, then safety is improved, but charge-discharge capacity may be reduced
Solution Approach 1:
The patent creates a composite solid electrolyte material combining Li2S with metal sulfides (FeS2, ZnS, or Bi2S3) and optionally metal oxides (Fe2O3, ZnO, Bi2O3). This composite structure leverages the high ionic conductivity of Li2S while the metal sulfides provide chemical stability and suppress hydrogen sulfide generation, achieving both safety and performance requirements simultaneously.
Solution Approach 2:
The metal sulfide components serve multiple functions: they maintain ionic conductivity pathways, suppress hydrogen sulfide generation through lower reactivity with water, and potentially enhance structural stability. This multi-functionality allows the material to simultaneously achieve safety requirements and maintain high charge-discharge capacity.
3Object-generated harmful factors
If hydrogen sulfide adsorbing material is added to the battery exterior to prevent leakage, then hydrogen sulfide leakage is reduced, but the generation of hydrogen sulfide inside the battery is not prevented
Solution Approach 1:
The patent takes preliminary action by modifying the solid electrolyte material composition before the battery is assembled or used. By incorporating metal sulfides with lower reactivity toward water into the electrolyte itself, the material is pre-configured to resist hydrogen sulfide generation at its source, eliminating the need for additional adsorbing materials in the battery structure.
Solution Approach 2:
The patent extracts the hydrogen sulfide generation problem from the system by addressing it at the material composition level rather than adding external mitigation components. The harmful reaction is removed by replacing the reactive P2S5 with stable metal sulfides, eliminating the need for separate hydrogen sulfide adsorption systems.
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 solution effectively suppresses hydrogen sulfide generation, enhances charge-discharge capacity, and allows for higher current densities while maintaining high conductivity, making the battery safer and more efficient.
Implementation Method 1
incorporating oxides that stabilize sulfur and improve conductivity, thereby suppressing hydrogen sulfide generation
Implementation Method 2
a solid electrolyte layer interposed between the positive electrode and the negative electrode, the solid electrolyte layer containing the above solid electrolyte material
Data Source
AI summary
A solid electrolyte material for an all solid-state lithium secondary battery represented by Li2S-MIaSb-MIIxOy, wherein MI is selected from P, Si, Ge, B and Al; “a” and “b” respectively represent numbers that give a stoichiometric ratio in accordance with the kind of MI; MII is selected from Fe, Zn and Bi; and “x” and “y” respectively represent numbers that give a stoichiometric ratio in accordance with the kind of MII.