Solid Electrolyte Material for High-Conductivity Batteries
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Solution Overview
Problem
Conventional solid electrolyte materials for batteries lack high lithium ion conductivity, and existing all-solid batteries using sulfide solid electrolytes can generate hydrogen sulfide when exposed to air, posing safety concerns.
Innovation Solution
A solid electrolyte material composed of Li, M, and X, where M is Y or other metalloid/metal elements, and X is Cl, Br, or I, with specific diffraction peak patterns and crystal structures, enhancing lithium ion conductivity and preventing hydrogen sulfide generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If LiCoO2 is used as the cathode material to achieve high output, then the battery capacity increases, but the battery explodes at high temperature
Solution Approach 1:
The patent uses LiCoO2 as the core material combined with LiMn2O4 as the shell material to form a composite cathode structure. This composite approach allows the high-capacity LiCoO2 core to be protected by the thermally stable LiMn2O4 shell, resolving the contradiction between achieving high battery capacity and maintaining thermal stability at high temperatures.
2Productivity
If the battery is charged at high speed to improve productivity, then charging time decreases, but Li deposits on the anode and battery life decreases
Solution Approach 1:
The patent introduces a Li3PO4 coating layer as an intermediary between the graphite anode and the electrolyte. This coating acts as a protective barrier that prevents direct contact between Li deposits and the graphite anode during high-speed charging, thereby allowing fast charging without significantly reducing battery life.
3Quantity of substance
If SiO2-coated graphite is used as the anode to improve capacity, then the anode capacity increases, but Li deposits on the anode during high speed charging
Solution Approach 1:
The patent creates a composite anode structure by coating SiO2 onto graphite particles and then forming a Li3PO4 layer on the surface. This multi-layer composite structure combines the high capacity of graphite with the protective properties of SiO2 and Li3PO4, preventing Li deposition during high-speed charging while maintaining high anode capacity.
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 material achieves high lithium ion conductivity and safety by preventing hydrogen sulfide generation, enabling the development of all-solid secondary batteries with improved charge/discharge characteristics and safety.
Implementation Method 1
a small amount of Li deposits on the anode when the battery is charged at high speed... it has gradually been found that this causes the battery life to decrease... Li3PO4 coating layer formed on the surface of the positive electrode
Implementation Method 2
it has gradually been found that batteries explode at high temperature... LiMn2O4 outer layer which suppresses release of oxygen from the LiCoO2 at high temperature
Implementation Method 3
a solid electrolyte interface (SEI) is formed on the anode
Data Source
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AI summary
Provide is a solid electrolyte material consisting of Li, M, X, and F, wherein M is Y, or includes Y and at least one kind selected from the group consisting of metalloid elements and metal elements other than Li; X is at least one kind selected from the group consisting of Cl, Br, and I; two or more peaks are present within a range where a value of a diffraction angle 2θ is not less than 24° and not more than 35° in an X-ray diffraction pattern of the solid electrolyte material using Cu-Ka as a radiation source; one or more peaks are present within a range where the value of the diffraction angle 2θ is not less than 40° and less than 48° in the X-ray diffraction pattern of the solid electrolyte material using Cu-Ka as the radiation source; and two or more peaks are present within a range where the value of the diffraction angle 2θ is not less than 48° and not more than 59° in the X-ray diffraction pattern of the solid electrolyte material using Cu-Ka as the radiation source.