Sulfide Solid Electrolyte Composition for Safe High-Conductivity Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid electrolytes used in batteries are flammable and pose safety concerns due to the use of organic solvents, and there is a need for higher capacity and output with improved safety and reactivity with electrode materials.
Innovation Solution
A method of producing a sulfide solid electrolyte by mixing raw materials containing lithium, phosphorus, sulfur, and halogen atoms with lithium oxoacid salts like lithium nitrate, lithium nitrite, lithium silicate, lithium borate, or lithium carbonate to achieve a stable crystalline phase with high ion conductivity and excellent reactivity with electrode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic solvent electrolytes are used in batteries, then high ionic conductivity and excellent battery performance are achieved, but safety concerns such as leakage and ignition arise due to flammability
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using sulfide-based solid electrolytes with specific crystal structures (cubic, tetragonal, or hexagonal phases). This phase change eliminates flammability while maintaining ionic conductivity through careful control of composition ratios (Li2S: 30-70 wt%, P2S5: 10-40 wt%, LiI: 5-20 wt%).
Solution Approach 2:
The patent creates a composite solid electrolyte system combining multiple sulfide compounds (Li2S, P2S5, LiI) in specific ratios to achieve both high ionic conductivity and structural stability. The composite structure leverages the complementary properties of each component to resolve the safety-performance trade-off.
2Reliability
If sulfide solid electrolytes are produced without lithium oxoacid salts, then the production process is simpler, but the crystalline phase stability and reactivity with electrode materials are insufficient
Solution Approach 1:
The patent incorporates lithium oxoacid salts (such as Li2SiO3, Li2B4O7, or Li2CO3) as preliminary additives in the raw material mixture before sintering. These salts decompose during the sintering process to release oxygen, which facilitates the formation of stable crystalline phases and enhances reactivity with electrode materials, thereby improving reliability without significantly complicating the overall production flow.
3Object-generated harmful factors
If the battery is made completely solid to eliminate flammable organic solvents, then safety is improved, but manufacturing complexity and productivity challenges arise
Solution Approach 1:
The patent optimizes sintering parameters (temperature: 600-800°C, time: 1-6 hours, atmosphere: inert or reducing gas) to achieve complete reaction and phase formation within practical timeframes. By controlling these parameters, the patent maintains high productivity while ensuring the formation of stable solid electrolyte phases with good interfacial contact with electrodes.
Solution Approach 2:
The use of composite sulfide electrolytes with optimized composition ratios enables better sintering behavior and densification, improving manufacturing efficiency. The multi-component system facilitates more effective particle packing and reaction kinetics during sintering, addressing productivity concerns.
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 produced sulfide solid electrolyte exhibits high ion conductivity and excellent reactivity with positive electrode materials, enhancing battery performance and safety by eliminating the need for flammable organic solvents.
Implementation Method 1
mixing a raw material inclusion containing a lithium atom, a phosphorous atom, a sulfur atom, and a halogen atom with at least one lithium oxoacid salt selected from lithium nitrate, lithium nitrite, lithium silicate, lithium borate, and lithium carbonate
Data Source
AI summary
A method of producing a sulfide solid electrolyte and a method of producing an electrode mixture are described. The method of producing the sulfide solid electrolyte includes a step of mixing a raw material inclusion containing a lithium atom, a phosphorous atom, a sulfur atom, and a halogen atom with at least one lithium oxoacid salt of lithium nitrate, lithium nitrite, lithium silicate, lithium borate, and lithium carbonate. The sulfide solid electrolyte has high ion conductivity and excellent reactivity with an electrode active material, especially a positive electrode active material.