Fluorine-Doped Garnet Electrolyte for Low-Temperature Sintering
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Solution Overview
Problem
Garnet-type oxide lithium secondary batteries face challenges in achieving sufficient sintering at low temperatures, leading to high grain boundary resistance and poor lithium ion conduction properties.
Innovation Solution
A lithium composite metal oxide electrolyte with the formula Li7-xLa3(Zr2-xAx)O12-yFy, where 0.1≤x≤1.0 and 0.0<y≤1.0, and A represents Ta, Nb, and Sb, is used, incorporating fluorine to enhance lithium ion conductivity and stabilize the electrolyte structure, allowing for improved sintering and ion conduction at lower firing temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If firing is performed at a low temperature, then energy consumption is reduced, but sufficient sintering does not occur at the interface between crystal grains leading to high grain boundary resistance
Solution Approach 1:
The patent introduces fluorine substitution (y>0) and multi-element doping (A=Ba, Sr, Ca; B=Ta, Nb, Sb) to modify the crystal structure and chemical composition of the garnet-type oxide. These compositional parameter changes enable sufficient sintering and reduced grain boundary resistance at lower firing temperatures, resolving the contradiction between energy consumption and reliability.
Solution Approach 2:
The patent creates a composite electrolyte material with multiple cation substitutions (A-site: Ba/Sr/Ca; B-site: Ta/Nb/Sb; fluorine anion substitution) to achieve synergistic effects. This composite approach enables low-temperature sintering while maintaining low grain boundary resistance, as the multiple dopants work together to facilitate grain boundary formation and ion conduction.
2Ease of manufacture
If firing is performed at a low temperature, then manufacturing cost is reduced, but lithium ion conduction property is insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters by introducing fluorine (y>0) and multi-element doping (A=Ba, Sr, Ca; B=Ta, Nb, Sb) to enable low-temperature processing. These compositional changes reduce the required firing temperature while maintaining or improving lithium ion conduction properties, thus reducing manufacturing cost without sacrificing performance.
Solution Approach 2:
The patent applies localized doping strategies where specific elements (Ba, Sr, Ca at A-site; Ta, Nb, Sb at B-site) are introduced to create favorable local environments for lithium ion conduction. The fluorine substitution at oxygen sites also creates localized structural modifications that facilitate ion transport, enabling good conduction properties at lower processing temperatures.
3Stability of the object's composition
If conventional garnet-type oxide is used, then material stability is maintained, but grain boundary resistance remains high due to insufficient sintering
Solution Approach 1:
The patent develops a composite garnet-type oxide with multiple cation substitutions (A=Ba, Sr, Ca; B=Ta, Nb, Sb) and fluorine anion substitution. This composite structure maintains the overall garnet-type crystal stability while creating favorable grain boundary characteristics through the synergistic effects of multiple dopants, thereby reducing grain boundary resistance.
Solution Approach 2:
The patent changes the compositional parameters by introducing fluorine (y>0) and multi-element doping to modify the crystal structure and chemical bonding characteristics. These parameter changes maintain material stability while improving grain boundary sintering behavior and reducing grain boundary resistance.
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 electrolyte achieves reduced grain boundary resistance and enhanced lithium ion conduction, improving the charge-discharge characteristics and capacity of lithium-ion batteries, even when fired at lower temperatures.
Implementation Method 1
incorporating fluorine to enhance lithium ion conductivity and stabilize the electrolyte structure
Implementation Method 2
when firing is performed at a low temperature, sufficient sintering does not occur at an interface between crystal grains
Implementation Method 3
improvement of the lithium ion conduction property
Data Source
AI summary
An electrolyte according to the present disclosure contains a lithium composite metal oxide represented by the following compositional formula.Li7-xLa3(Zr2-xAx)O12-yFy In the formula, 0.1≤x≤1.0, 0.0<y≤1.0, and A represents two or more types of Ta, Nb, and Sb.