Garnet-Type Solid-State Electrolyte for High-Voltage Batteries
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Solution Overview
Problem
Current lithium-ion batteries face challenges with stability and ionic conductivity, particularly when using high-voltage positive electrode materials and low-voltage negative electrode materials like lithium metal, as existing solid-state materials are not sufficiently stable and have lower lithium conductivity compared to liquid alternatives.
Innovation Solution
A solid-state electrolyte comprising a garnet-type oxide material with a specific compound formula, Li7-a*α-(b−4)*β−xMaαLa3Hf2−βMbβO12−x−δXx, is developed, which improves lithium-ion conductivity and stability by optimizing the valence of cationic and anionic elements and incorporating oxygen defects, and can be used as a separator, protection layer, or integrated into electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid-state materials are used as electrolytes, then safety and energy density are improved, but lithium conductivity is significantly lower than liquid alternatives
Solution Approach 1:
The patent modifies the chemical composition parameters of the garnet-type oxide electrolyte by controlling the valence of cationic elements (Ma, Mb) and anionic elements (X), and by optimizing oxygen defect content (δ). These parameter changes enable the solid-state electrolyte to achieve lithium conductivity comparable to liquid alternatives while maintaining safety advantages.
Solution Approach 2:
The patent creates a composite garnet-type oxide material combining multiple cationic elements (Ma, Mb) with specific valences and oxygen defects within the Li7-a*α-(b−4)*β−xMaαLa3Hf2−βMbβO12−x−δXx formula. This composite structure optimizes both ionic conductivity and electrochemical stability simultaneously.
2Quantity of substance
If high-voltage positive electrode materials and low-voltage negative electrode materials like lithium metal are used, then energy density is improved, but material stability is insufficient
Solution Approach 1:
The patent adjusts the electrochemical stability parameters of the garnet-type oxide electrolyte by optimizing the valence states of cationic elements (a+, b+) and anionic elements (-1), and by controlling oxygen defect concentration (δ). These parameter changes expand the electrochemical stability window to accommodate high-voltage positive electrodes and lithium metal negative electrodes.
3Ease of manufacture
If conventional solid-state electrolyte compositions are used, then manufacturing is simplified, but power density is limited
Solution Approach 1:
The patent optimizes the compositional parameters within the garnet-type oxide formula Li7-a*α-(b−4)*β−xMaαLa3Hf2−βMbβO12−x−δXx, specifically tuning the ratios of cationic elements and oxygen defect content. These parameter optimizations enhance lithium ion mobility and conductivity, thereby increasing power density while maintaining compatibility with conventional solid-state electrolyte manufacturing processes.
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 enhances the stability and ionic conductivity of lithium-ion batteries, enabling the use of high-voltage positive and low-voltage negative electrodes, thereby improving power density and safety.
Implementation Method 1
The lithium conductivity of available solid-state materials is significantly less than liquid alternatives
Data Source
AI summary
Disclosed is a solid state electrolyte comprising a compound of Formula 1Li7-<sub2>a</sub2>*α-(b−4)*β−xMaαLa3Hf2−βMbβO12−x−δXx (1)whereinMa is a cationic element having a valence of a+;Mb is a cationic element having a valence of b+; andX is an anion having a valence of −1,wherein, when Ma includes H, 0≤α≤5, otherwise 0≤α≤0.75, and wherein 0≤β≤1.5, 0≤x≤1.5, and (a*α+(b−4)β+x)>0, 0≤δ≤1.