Lithium-Phosphate-Coated Sulfide Solid Electrolyte for Ion Conductivity
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Solution Overview
Problem
Solid electrolytes face challenges such as low ion conductivity, interface resistance with solid particles, and ion conduction performance deterioration due to solid-to-solid bonding, particularly in all-solid-state batteries.
Innovation Solution
A solid electrolyte comprising sulfide solid electrolyte particles coated with lithium-metal-phosphate, heat-treated between 250° C. to 350° C., which improves ion conductivity and crystallinity while preventing particle aggregation, and includes a method of mixing sulfur-containing raw materials and performing multiple heat treatments to achieve appropriate particle size distribution and moisture stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolyte particles are used in all-solid-state batteries, then battery safety is improved, but ion conductivity deteriorates
Solution Approach 1:
The patent applies composite materials by combining sulfide solid electrolyte particles with lithium-metal-phosphate coating to create a composite solid electrolyte structure. This composite approach maintains the safety benefits of solid electrolytes while improving ion conductivity through the synergistic effect of the coating layer, directly resolving the contradiction between safety and ion conductivity.
2Ease of manufacture
If solid-to-solid bonding is used in battery assembly, then manufacturing simplicity is improved, but ion conduction performance deteriorates due to depletion layer formation
Solution Approach 1:
The patent applies local quality by creating a specific coating layer (lithium-metal-phosphate) on the surface of solid electrolyte particles. This localized modification improves ion conduction at the critical particle surfaces where depletion layers form during solid-to-solid bonding, while maintaining the overall simplicity of solid electrolyte assembly.
3Quantity of substance
If heat treatment is performed to improve crystallinity, then ion conductivity is improved, but particle aggregation occurs
Solution Approach 1:
The patent applies preliminary action by performing heat treatment at controlled temperatures (250-350°C) for specific durations (0.5-10 hours) before battery assembly. This preliminary heat treatment improves crystallinity and ion conductivity of the solid electrolyte particles while controlling particle size distribution, preventing aggregation during subsequent battery manufacturing processes.
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 enhances ion conductivity, maintains high crystallinity, and ensures uniform particle size distribution, leading to improved battery performance in terms of energy density, charge/discharge efficiency, and cycle-life characteristics.
Implementation Method 1
a solid electrolyte, compared to the liquid electrolyte, has problems of low ion conductivity, resistance on the interface with solid particles of a positive electrode active material
Implementation Method 2
mixing sulfide solid electrolyte particles and lithium-metal-phosphate and performing a heat treatment at about 250° C. to about 350° C.
Implementation Method 3
in an X-ray diffraction analysis of the solid electrolyte, a full width at half maximum (FWHM) of a main peak is less than or equal to about 0.160
Data Source
AI summary
A solid electrolyte, including a sulfide solid electrolyte particle and lithium-metal-phosphate on the surface of the sulfide solid electrolyte particles wherein in an X-ray diffraction analysis of the solid electrolyte, a full width at half maximum (FWHM) of a main peak is less than or equal to about 0.160.