Garnet Solid Electrolyte for Safe Li-Ion Batteries
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Solution Overview
Problem
Current solid-state lithium ion batteries face challenges with low ion conductivity, compatibility issues with lithium metal anodes and high voltage cathodes, flammability, and high manufacturing costs due to the use of liquid electrolytes, and existing solid electrolytes like Li2PO2N and sulfide glasses have limitations in scalability and toxicity.
Innovation Solution
A ceramic garnet-based ionically conducting material with the formula LiwAxM2Re3−yOz, where w is 5-7.5, A is selected from certain metals, M is from a specific group of elements, Re is from lanthanide or actinide elements, and y is 0.01-0.75, exhibiting a garnet-type crystal structure, which offers improved low temperature conductivity and reduced rare earth content, enabling higher ion conductivity and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolyte is used in SOA Li-ion batteries, then ion conduction is achieved, but flammability and safety risks increase
Solution Approach 1:
The patent changes the physical state parameter of the electrolyte from liquid to solid, specifically using a ceramic garnet-based solid electrolyte. This phase change eliminates flammability while maintaining ion conduction capability, directly resolving the safety contradiction.
Solution Approach 2:
The patent employs a composite ceramic material with garnet-type crystal structure (Li7-xLaxZr2-yTiyO12) that combines multiple elements to achieve both high ion conductivity and intrinsic safety. The composite nature provides both functional performance and safety properties simultaneously.
2Reliability
If solid electrolyte is used to replace liquid electrolyte, then safety and energy density are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the chemical composition parameters of the solid electrolyte (Li7-xLaxZr2-yTiyO12) to achieve sintering temperatures around 900-1100°C, which are compatible with conventional ceramic manufacturing equipment. This parameter optimization reduces manufacturing complexity while maintaining safety benefits.
3Reliability
If conventional solid electrolytes like LiPON or sulfide glasses are used, then safety is improved, but manufacturing scalability is limited
Solution Approach 1:
The patent modifies the composition parameters to achieve sintering at 900-1100°C, enabling conventional ceramic processing techniques. This temperature parameter change allows for scalable manufacturing using established industrial processes, unlike LiPON requiring vapor deposition or sulfide glasses requiring toxic H2S handling.
Solution Approach 2:
The patent uses abundant, non-toxic ceramic materials that can be processed using conventional equipment, replacing expensive and specialized materials like LiPON. This approach enables cost-effective, scalable manufacturing without specialized facilities.
4Reliability
If garnet-based solid electrolyte is used, then ion conductivity is improved, but rare earth content increases cost
Solution Approach 1:
The patent optimizes the compositional parameters (x and y values in Li7-xLaxZr2-yTiyO12) to achieve high ion conductivity with reduced rare earth content. The titanium doping parameter (y) is specifically tuned to enhance conductivity while minimizing lanthanum (x) content, thereby reducing cost.
Solution Approach 2:
The patent substitutes expensive rare earth elements with more abundant and cheaper alternatives, specifically using titanium doping to maintain high ion conductivity. This material substitution reduces manufacturing cost while preserving the essential functional performance.
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 ceramic material achieves fast ion conduction with a room temperature conductivity of 0.37 mS/cm, low activation energy, and stability, suitable for various applications including automotive and consumer electronics, while reducing geopolitical risks and manufacturing costs.
Implementation Method 1
The ceramic material achieves fast ion conduction with a room temperature conductivity of 0.37 mS/cm
Data Source
AI summary
Disclosed is a ceramic material having a formula of LiwAxM2Re3-yOz, wherein w is 5-7.5; wherein A is selected from B, Al, Ga, In, Zn, Cd, Y, Sc, Mg, Ca, Sr, Ba, and any combination thereof; wherein x is 0-2; wherein M is selected from Zr, Hf, Nb, Ta, Mo, W, Sn, Ge, Si, Sb, Se, Te, and any combination thereof; wherein Re is selected from lanthanide elements, actinide elements, and any combination thereof; wherein y is 0.01-0.75; wherein z is 10.875-13.125; and wherein the material has a garnet-type or garnet-like crystal structure. The ceramic garnet based material is ionically conducting and can be used as a solid state electrolyte for an electrochemical device such as a battery or supercapacitor.