Lithium Salt Film Spray Pyrolysis for Thick Coating Control
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Solution Overview
Problem
Current physical vapor deposition (PVD) methods for depositing lithium salt thin films are limited by low deposition rates, inability to coat large areas, difficulty in controlling film thickness and morphology, and the high costs and complexity of vacuum-based processes.
Innovation Solution
The use of spray pyrolysis to deposit alkali metal salts, alkaline earth metal salts, and composite metal salts onto substrates, allowing for the formation of films with controlled thickness, morphology, and composition, without the need for vacuum conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical vapor deposition (PVD) processes are used to deposit lithium salt films, then film deposition can be achieved, but deposition rates are low (e.g., about 100 nm per hour) making it unsuitable for thicker films
Solution Approach 1:
The invention changes the fundamental deposition parameters by transitioning from vacuum-based PVD to atmospheric pressure spray pyrolysis. This allows deposition rates to increase from ~100 nm/hour to several micrometers per hour, enabling production of thicker films (1-100 μm) while maintaining thickness control through spray rate and substrate temperature parameters.
Solution Approach 2:
The invention replaces the mechanical vacuum system with a chemical solution-based spray pyrolysis system. Instead of using vacuum pumps and plasma fields to deposit material, the process uses aerosol spray delivery and thermal decomposition at atmospheric pressure, dramatically increasing deposition speed and enabling thicker film production.
2Manufacturing precision
If PVD processes are used to deposit films, then thin films can be formed, but it is difficult to control film thickness and morphology
Solution Approach 1:
The spray pyrolysis process incorporates feedback control through monitoring substrate temperature and adjusting spray rate accordingly. The substrate temperature (maintained at 150-450°C) provides feedback on deposition conditions, allowing real-time adjustment of spray parameters to achieve desired film thickness and morphology while reducing total deposition time.
Solution Approach 2:
The invention introduces dynamic control of deposition parameters including variable spray rate, adjustable substrate temperature, and controlled heating rates during annealing. This dynamic parameter adjustment enables precise control of film thickness and morphology (amorphous vs. crystalline) while maintaining high productivity through faster deposition rates.
3Ease of manufacture
If vacuum conditions are used for PVD processes, then film deposition can proceed, but the processes are expensive and difficult to scale-up
Solution Approach 1:
The invention extracts and removes the vacuum system from the deposition process entirely. By conducting spray pyrolysis at atmospheric pressure, the process eliminates expensive vacuum pumps, pressure control systems, and associated infrastructure, dramatically reducing equipment costs and enabling easy scale-up to large-area substrates without the engineering challenges of maintaining vacuum in large chambers.
Solution Approach 2:
The spray pyrolysis process uses inexpensive, readily available materials including water-based precursor solutions, common solvents (alcohols, esters, carbonates), and standard atmospheric conditions. This replaces expensive vacuum-grade gases and specialized equipment with cheap, easily obtained materials, making the process economically attractive and scalable.
4Area of stationary object
If PVD processes are used to deposit films on small areas, then deposition can be achieved, but it is not well-suited for depositing films over larger areas
Solution Approach 1:
The spray pyrolysis process transitions from the point-by-point or line-by-line deposition typical of PVD to a volumetric aerosol spray approach. The precursor solution is atomized into fine droplets that distribute uniformly across the substrate surface in three-dimensional space, enabling coverage of large areas (several square feet) while maintaining film uniformity through consistent droplet distribution and controlled substrate temperature.
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 deposition of lithium salt films with thicknesses ranging from 300 nm to 100 μm, offering improved control over film properties and reducing production costs by eliminating the need for vacuum equipment.
Implementation Method 1
spray pyrolysis to deposit alkali metal salts, alkaline earth metal salts, and composite metal salts
Implementation Method 2
the precursor film is annealed to form the metal salt film
Implementation Method 3
the substrate may be heated with a heating element thermally coupled to the substrate
Implementation Method 4
spraying a mixture onto the substrate to form a precursor film
Data Source
AI summary
A method for making a lithium salt film includes heating a substrate, spraying a mixture with a spray nozzle onto the substrate to form a precursor film, and annealing the precursor film to form the lithium salt film. The lithium salt film has a thickness of about 400 nm to about 100 pm. The spray mixture includes a first precursor comprising a lithium ion, a second precursor comprising an anion, and a solvent.