LLZO Synthesis Using Nanocrystalline Precursors
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Solution Overview
Problem
Existing methods for synthesizing lithium lanthanum zirconate (LLZO) face challenges in achieving stable, highly conducting cubic phases without extrinsic dopants, while also requiring high temperatures and complex processes.
Innovation Solution
The synthesis of LLZO thin films is achieved by forming a slurry with lanthanum zirconate (LZO) nanocrystals, lithium-containing compounds, and optional dopants, which is then calcined and sintered to produce LLZO with fine grain structure and superior mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional synthesis methods are used to produce LLZO, then high temperature processing is required, but this increases energy consumption and processing complexity
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing nanocrystalline LZO particles with controlled size and morphology before the main LLZO synthesis. This pre-prepared nanocrystalline precursor enables lower temperature processing in the subsequent solid-state reaction, reducing energy consumption while maintaining product quality
Solution Approach 2:
The patent changes physical parameters by reducing particle size to nanometric dimensions and controlling crystal structure (cubic pyrochlore phase). These parameter changes in the precursor material enable the main reaction to proceed at lower temperatures, directly addressing the energy consumption issue
2Stability of the object's composition
If extrinsic dopants are added to stabilize cubic phase LLZO, then phase stability is improved, but material purity and performance are compromised
Solution Approach 1:
The patent applies self-service by designing a self-stabilizing nanocrystalline LZO precursor that inherently maintains the desired cubic phase structure through its nanoscale characteristics and controlled composition. This eliminates the need for extrinsic dopants, allowing the material to stabilize itself and achieve superior intrinsic performance
Solution Approach 2:
The patent changes compositional parameters by controlling the La:Zr ratio and maintaining nanocrystalline structure, which inherently stabilizes the cubic phase without requiring additional dopant elements. This parameter optimization achieves phase stability while preserving material purity
3Manufacturing precision
If nanometric dimensions are used for LLZO, then densification and sintering properties are enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing nanocrystalline LZO particles with controlled size distribution and morphology before the main LLZO formation. This pre-controlled nanocrystalline precursor makes it easier to achieve uniform grain size and high densification in the final product, as the nanoscale building blocks self-organize during sintering
Solution Approach 2:
The patent applies segmentation by dividing the final LLZO structure into nanocrystalline building blocks with controlled size and shape. These segmented nanoparticles provide better packing efficiency and sintering behavior, enhancing densification while the controlled segmentation maintains manufacturing feasibility
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
This method enables the stabilization of the cubic phase of LLZO without dopants, enhances densification and sintering properties, and allows for lower temperature and cost-effective preparation, resulting in flexible, non-brittle LLZO films suitable for battery applications.
Implementation Method 1
The dried slurry is calcined to yield the layer including lithium lanthanum zirconate
Implementation Method 2
The dried slurry is calcined to yield the layer including lithium lanthanum zirconate
Implementation Method 3
Calcining the dried slurry can include heating the dried slurry at a temperature between 700° C. and 1200° C. for a few minutes to several hours
Data Source
AI summary
Fabricating a layer including lithium lanthanum zirconate (Li7La3Zr2O12) layer includes forming a slurry including lanthanum zirconate (La2Zr2O7) nanocrystals, a lithium precursor, and a lanthanum precursor in stoichiometric amounts to yield a dispersion including lithium, lanthanum, and zirconium. In some cases, the dispersion includes lithium, lanthanum, and zirconium in a molar ratio of 7:3:2. In certain cases, the slurry includes excess lithium. The slurry is dispensed onto a substrate and dried. The dried slurry is calcined to yield the layer including lithium lanthanum zirconate.