Doped Li6Hf2O7 Solid Electrolyte for Battery Stability
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Solution Overview
Problem
Current solid-state lithium ion conductors and lithium metal batteries face stability issues with lithium metal and have lower conductivity compared to liquid alternatives, necessitating an improved material for enhanced safety and performance.
Innovation Solution
Development of a doped Li6Hf2O7-type compound with specific dopants and lithium stoichiometry, which increases lithium conductivity and stability, allowing for improved lithium metal battery performance and protection against air and moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid-state electrolyte materials are used to improve safety, then stability is improved, but lithium conductivity is significantly reduced compared to liquid alternatives
Solution Approach 1:
The patent modifies the chemical composition parameters of the solid-state electrolyte by incorporating specific dopants (Y3+, In3+, Zn2+) at controlled concentrations (0.1 ≤ x ≤ 0.5) into the Li6Hf2O7 lattice structure. This doping strategy changes the electrical and ionic parameters of the material, enabling it to achieve lithium conductivity comparable to liquid electrolytes while maintaining the safety advantages of solid-state materials.
Solution Approach 2:
The patent creates a composite solid-state electrolyte material by combining Li6Hf2O7 with dopant elements (Y3+, In3+, Zn2+) to form a doped compound with improved properties. The composite structure integrates the stability of the base Li6Hf2O7 material with the enhanced ionic conductivity contributed by the dopants, resolving the contradiction between safety and conductivity.
2Use of energy by moving object
If lithium metal is used to improve specific energy and energy density, then power density is improved, but stability to lithium metal is insufficient
Solution Approach 1:
The doped Li6Hf2O7 solid-state electrolyte acts as an intermediary layer between the lithium metal electrodes and the external environment. This intermediate material provides a stable interface that maintains electrical contact while preventing direct exposure to moisture and air, thereby preserving both the high energy density benefits of lithium metal and the required stability.
Solution Approach 2:
The patent employs the doped Li6Hf2O7 material to create an inert protective environment around the lithium metal. The stable crystal structure and surface properties of the doped electrolyte form a protective barrier that isolates the reactive lithium metal from atmospheric moisture and oxygen, enabling safe operation while maintaining high energy density.
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 doped compound achieves enhanced lithium ionic conductivity and stability, reducing the risk of short-circuits and improving battery safety and efficiency.
Implementation Method 1
the lithium conductivity of available solid-state electrolytes is significantly less than liquid alternatives
Implementation Method 2
heat-treating the mixture to prepare the compound
Data Source
AI summary
A compound of Formula 1:Li6+(4−a)x+c)M4+(2−x)Aa+xO(7−c)N′c (1)wherein M is a tetravalent cationic element, A is a divalent or trivalent cationic element, N′ is an anion having a valence of less than −2, wherein when A is Y3+, In3+, Zn2+, or a combination thereof, 0.15<x≤0.5, otherwise 0≤x≤0.5, 0≤c≤2, and ((4−a)x+c)>0.