Doped Solid-State Electrolyte for Lithium-Stable Battery Interfaces
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Solution Overview
Problem
Conventional solid-state batteries face issues with the detachment of the solid-state electrolyte from the anode, and existing materials lack sufficient ionic conductivity and stability when in contact with lithium metal.
Innovation Solution
A compound represented by Formula Li4+dH+hSr2−xM1a+xZr1−yM2b+yO6−zXc−z is developed, which includes dopants in the strontium, zirconium, and oxygen sites to enhance lithium stability and ionic conductivity, with a stoichiometry that accommodates excess lithium, improving interstitial accommodation and charge compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid-state electrolyte is used to improve safety, then safety is improved, but detachment from anode occurs
Solution Approach 1:
The patent modifies the chemical composition parameters of the solid-state electrolyte by incorporating specific dopants (M1 at Sr sites, M2 at Zr sites, and X at O sites) in controlled amounts. This changes the material's properties to achieve both safety and adhesion, resolving the contradiction between safety improvement and detachment prevention.
Solution Approach 2:
The patent creates a composite solid-state electrolyte material by combining multiple elements (Li, Sr, Zr, M1, M2, O, X) in a specific composite structure. This composite approach enables the material to simultaneously provide safety benefits while preventing detachment through optimized composition and interfacial properties.
2Reliability
If conventional solid-state electrolyte is used, then safety is improved, but ionic conductivity is insufficient
Solution Approach 1:
The patent optimizes ionic conductivity by carefully adjusting compositional parameters including the amounts of dopants (a, b, c values), stoichiometric ratios (Li:Zr > 4:1, Li:O > 4:6), and structural parameters (x, y, z, h). These parameter changes enable high ionic conductivity while maintaining safety.
Solution Approach 2:
The patent introduces local quality variations through dopant placement at specific crystallographic sites (M1 at Sr sites, M2 at Zr sites, X at O sites). This localized modification of the crystal structure creates favorable regions for ion transport while maintaining overall material stability and safety.
3Reliability
If solid-state electrolyte is used, then safety is improved, but stability against lithium metal is insufficient
Solution Approach 1:
The patent achieves lithium metal stability by optimizing compositional parameters including the Li excess (d≥0), dopant concentrations (a, b, c), and stoichiometric ratios. These parameter adjustments create a chemically stable interface with lithium metal while preserving safety benefits.
Solution Approach 2:
The patent converts the potential harm of lithium metal reactivity into a benefit by designing a composition that accommodates excess lithium (d≥0) and uses specific dopants to create a stable interface. The lithium excess and dopant structure transform the reactive interface into a stable, protective configuration.
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 compound achieves high ionic conductivity of about 0.3 mS/cm at room temperature and improved lithium stability, reducing activation energy and ensuring safer operation compared to sulfide-based materials.
Implementation Method 1
The compound has an ionic conductivity of about 0.3 mS/cm or greater at room temperature
Implementation Method 2
M1 is a cationic dopant in Sr site with a valance of a+; M2 is a cationic dopant in Zr site with a valance of b+; X is an anion dopant in O site with a valence of c−
Data Source
AI summary
A compound represented by Formula 1:Li4+dH+hSr2−xM1a+xZr1−yM2b+yO6−zXc−z,wherein in Formula 1, M1 is a cationic dopant in Sr site with a valance of a+; a is 1, 2 or 3; M2 is a cationic dopant in Zr site with a valance of b+; b is 2, 3, 4 or 5; X is an anion dopant in O site with a valence of c−; c is 1, 2, or 3; 0≤h≤2, 0≤x≤2, 0≤y≤1, 0≤z≤0.5, x+y+z+h≥0, d=(2−a)*x+(4−b)*y−(2−c)*z−h, and d≥0.