Al-LLZO Thin-Tape Electrolytes via Flame Spray Pyrolysis
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Solution Overview
Problem
Current methods for synthesizing oxide-based solid-state electrolytes (SSEs) are either too expensive and complex or require extensive post-processing steps and long high-temperature heat treatments, which hinder the production of high-quality, thin, and dense SSEs for solid-state batteries.
Innovation Solution
The method involves flame-assisted spray pyrolysis (FASP) to synthesize aluminum-doped lithium lanthanum zirconate oxide (Al-LLZO) powders, which are then processed through tape casting to produce thin-tape SSEs. This method includes forming droplets of a precursor solution, preheating, generating a flame, decomposing the droplets, depositing as-synthesized particles, and heating them in a furnace with an oxidizing agent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional synthesis methods are used to produce oxide-based SSEs, then the material can achieve sufficient density and crystallinity, but the process requires long high-temperature heat treatments and extensive post-processing steps
Solution Approach 1:
The precursor solution is prepared with all metal nitrates and chelating agents in correct stoichiometric ratios before synthesis, ensuring proper composition is established beforehand. The droplets are preheated to evaporate solvents and initiate decomposition before entering the main flame zone, reducing the time needed for complete transformation
Solution Approach 2:
The synthesis utilizes rapid phase transitions through flame-assisted spray pyrolysis, where the precursor solution transitions from liquid droplets to solid particles through rapid evaporation, decomposition, and crystallization in the flame zone. This allows achieving crystallinity without prolonged high-temperature heat treatment
2Manufacturing precision
If conventional synthesis methods are used to produce oxide-based SSEs, then the material can achieve sufficient density and crystallinity, but the process becomes expensive and complex
Solution Approach 1:
Multiple synthesis steps are merged into a single flame-assisted spray pyrolysis process. The precursor preparation, droplet formation, heating, decomposition, and particle formation occur in one continuous operation, eliminating the need for separate mixing, drying, and heat treatment steps required by conventional methods
Solution Approach 2:
The conventional mechanical mixing and high-temperature sintering processes are replaced with a chemical field-based approach using flame-assisted spray pyrolysis. The chemical energy of the flame directly transforms the precursor solution into crystalline particles, substituting mechanical and thermal processing with a chemical transformation process
3Reliability
If thin-tape SSEs are produced to ensure good rate performance, then the ionic conductivity improves, but the synthesis requires even more precise control and additional processing steps
Solution Approach 1:
The synthesis produces fine particles with controlled morphology that can be easily processed into thin tapes. The flame-assisted spray pyrolysis creates discrete particles that flow well and pack uniformly, facilitating the formation of thin, dense tapes without requiring complex processing equipment or multiple fabrication steps
Solution Approach 2:
By adjusting flame temperature, precursor concentration, and spray rate, the particle size and morphology are controlled to optimize tape formation. These parameter changes enable the production of thin-tape SSEs with good density and crystallinity while maintaining ease of manufacture through simple process adjustments
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
FASP enables the production of high-quality Al-LLZO powders with controlled morphology, which can be used to fabricate thin-tape SSEs with improved electrochemical stability and ionic conductivity, thus addressing the challenges of existing synthesis methods.
Implementation Method 1
aerosolizing the precursor solution in a stream of air using an ultrasonic nebulizer to form droplets
Implementation Method 2
decomposing the droplets by passing through the burner
Implementation Method 3
generating a flame in a burner, decomposing the droplets by passing through the burner
Implementation Method 4
heating the ASP in a furnace in the presence of an oxidizing agent to produce the aluminum-doped lithium lanthanum zirconate oxide
Data Source
AI summary
A method of synthesis of aluminum-doped Li6.25Al0.25La3Zr2O12 (Al-LLZO) can include preparing a precursor solution by dissolving lithium nitrate, aluminum nitrate, zirconium (IV) oxynitrate, and lanthanum nitrate in stoichiometric amounts according to the composition Li6.25Al0.25La3Zr2O12 in water, and decomposing droplets by passing through a co-flow burner. Also disclosed is a method of produce producing a thin-tape comprising Al-LLZO.