Lithium Ion Conductive Glass-Ceramics Microvoid Reduction
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Solution Overview
Problem
All solid lithium ion batteries require improved lithium ion conductivity for commercialization, as existing lithium ion conductive glass-ceramics are prone to developing microvoids during crystallization, which decreases conductivity.
Innovation Solution
A glass-ceramics composition with specific crystalline structures, including LiTi2P3O12 and AlPO4, optimized to minimize microvoids, with a composition of Li2O, Al2O3, SiO2, P2O5, TiO2, and ZrO2, and heat-treated to achieve high lithium ion conductivity and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass-ceramics is produced by heat treating molded glass to precipitate crystallines, then lithium ion conductivity is improved compared to sintered ceramic, but microvoids develop during crystallization which decrease conductivity
Solution Approach 1:
The patent applies parameter changes by carefully controlling heat treatment parameters (temperature range of 850-1050°C, heating rate of 50-1200°C/h, duration of 24 hours or less) to achieve crystallization that minimizes microvoid formation while maintaining high lithium ion conductivity. This resolves the contradiction by optimizing the crystallization process parameters.
Solution Approach 2:
The patent uses a composite glass-ceramics material containing specific crystalline phases (LiTi2P3O12 and AlPO4) embedded in a glass matrix. This composite structure achieves high density and low microvoid content while maintaining processability, resolving the contradiction between conductivity improvement and microvoid formation.
2Manufacturing precision
If glass-ceramics is produced by molding molten glass and heat treating, then manufacturing precision is improved by reducing voids compared to sintered ceramic, but microvoids still form during crystallization
Solution Approach 1:
The patent optimizes heat treatment parameters (temperature, heating rate, duration) to control the crystallization process, achieving high density uniformity while minimizing microvoid formation through precise parameter control during manufacturing.
Solution Approach 2:
The patent performs preliminary glass molding to create a dense green body before heat treatment, which provides a foundation that resists microvoid formation during subsequent crystallization, improving overall manufacturing precision.
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 achieves high lithium ion conductivity of 5 x 10^-5 S/cm or more at 25°C and a specific gravity of 2.6 to 3.0, reducing microvoids and enhancing the density of the solid electrolyte, thereby improving battery performance.
Implementation Method 1
heat treating the molded glass to precipitate (crystallize) lithium ion conductive crystallines
Implementation Method 2
The glass-ceramics is produced by heat treating a raw glass thereby precipitating crystallines
Data Source
Figure 1
AI summary
There is provided a lithium ion conductive glass-ceramics which is dense, contains few microvoids causing the decrease in lithium ion conductivity, and achieves good lithium ion conductivity. A glass-ceramics which comprises at least crystallines having an LiTiP3O12 structure, the crystallines satisfying 1 <IA113/IA104 ≤ 2, wherein IA104 is the peak intensity assigned to the plane index 104 (2θ = 20 to 21°), and IA113 is the peak intensity assigned to the plane index 113 (2θ = 24 to 25°) as determined by X-ray diffractometry.