High-Entropy Li-Garnet Electrolyte for Tougher Solid-State Batteries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid-state batteries with ceramic solid-state electrolytes face challenges in mechanical properties, such as brittleness and low fracture toughness, which affect their ability to withstand stresses during charging and cycling, limiting their energy density and cycle life.
Innovation Solution
A high-entropy Li-garnet electrolyte with a chemical formula of Li7La3Zr0.5Nb0.5Ta0.5Hf0.5O12 is developed, incorporating equimolar amounts of Zr, Nb, and Hf, which enhances ionic conductivity, mechanical properties, and microstructures through doping engineering, resulting in improved densification, hardness, and flexural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic solid-state electrolyte is used to improve safety and energy density, then safety and energy density are improved, but mechanical properties deteriorate due to brittleness and low fracture toughness
Solution Approach 1:
The patent applies composite materials by combining multiple dopant elements (Ta, Nb, Hf, Zr) in the Li-garnet electrolyte structure. This multi-element doping creates a composite ceramic material that achieves both improved mechanical properties (flexural strength of 84.8±6.9 MPa, hardness of 8.5±0.8 GPa) and maintained ionic conductivity (4.67×10−4 S cm−1), resolving the contradiction between safety/reliability and mechanical strength
Solution Approach 2:
The patent employs parameter changes by precisely controlling the dopant composition ratios (Li7La3Zr0.5Nb0.5Ta0.5Hf0.5O12) and sintering conditions (temperature, time, atmosphere) to optimize the microstructure. This achieves enhanced mechanical properties while maintaining adequate ionic conductivity, simultaneously improving both safety and mechanical performance
2Use of energy by moving object
If ceramic solid-state electrolyte is used to increase energy density, then energy density is improved, but mechanical integrity deteriorates under stress during charging and cycling
Solution Approach 1:
The multi-element doped Li-garnet electrolyte (Li7La3Zr0.5Nb0.5Ta0.5Hf0.5O12) acts as a composite material that provides both high energy density capability and enhanced mechanical integrity. The synergistic effect of multiple dopants creates a robust microstructure that maintains integrity under charging/discharging stresses while enabling high energy density operation
Solution Approach 2:
The patent applies local quality by creating a homogeneous distribution of multiple dopant elements at the atomic scale within the garnet structure. This uniform local composition throughout the material provides consistent mechanical reinforcement and ionic conductivity pathways, ensuring stable performance during cycling
3Strength
If multi-element doping is applied to improve mechanical properties, then mechanical properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing all dopant elements (Ta2O5, Nb2O5, HfO2, ZrO2) with LiOH·H2O and La2O3 before sintering. This preliminary homogeneous mixing simplifies the manufacturing process compared to sequential doping, reducing complexity while achieving the desired multi-element composition and improved mechanical properties
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 high-entropy Li-garnet electrolyte achieves a relative density of 93-94%, ionic conductivity of 4.67×10−4 S cm−1, and mechanical properties like flexural strength of 84.8±6.9 MPa and hardness of 8.5±0.8 GPa, addressing the mechanical limitations of traditional Li-garnet electrolytes and enhancing the performance of solid-state batteries.
Implementation Method 1
The present invention provides a high-entropy solid-state electrolyte whereby the ability to dope multi-elements in the solid-state electrolyte can improve the properties, modify the microstructures
Implementation Method 2
Li-garnet (LixLa3M2O12, where x is in the range of 6-7, M=Zr, Ta, Nb, etc.) is one of the most promising candidates due to the adequate ionic conductivity (approaching 10−3 S/cm)
Implementation Method 3
The powder can be densified to a density of about 93-94% at a temperature of about 1100° C.
Data Source
AI summary
The present invention provides a novel high-entropy Li-garnet electrolyte with the chemical formula of Li7La3Zr0.5Nb0.5Ta0.5Hf0.5O12, in which Zr, Nb, Ta, and Hf of equimolar amounts are on the Zr site in LLZO. The present invention also provides a novel method of manufacturing said high-entropy Li-garnet electrolyte.