Amorphous Lithium-Silicon Organic Glass Electrolyte Conformal Deposition
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Solution Overview
Problem
Current solid electrolytes for lithium microbatteries face issues with low ionic conductivity and chemical stability, particularly due to the formation of crystalline zones in polymer electrolytes and the limitations of glass electrolytes like LiPON, which have low conductivity and are not conformally depositable.
Innovation Solution
A solid, amorphous organic glass electrolyte with the formula Si v O w C x H y, where v, w, x, y, and z are atomic percentages within specific ranges, is developed, allowing for conformal deposition and enhanced ionic conductivity, stability, and compatibility with microelectronics processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic glass electrolytes like LiPON are used, then electrochemical stability against lithium is improved, but ionic conductivity deteriorates (relatively low ionic conductivity of the order of 2 x 10^-6)
Solution Approach 1:
The patent applies composite materials by combining inorganic glass components (SiO2, B2O3, P2O5) with organic components (cyclic carbonates like EC, PC, GC) to create a hybrid electrolyte system. This composite approach allows the electrolyte to simultaneously achieve the electrochemical stability of inorganic glasses and the high ionic conductivity of organic electrolytes, resolving the contradiction between stability and conductivity.
Solution Approach 2:
The patent employs parameter changes by systematically varying the composition ratios of inorganic oxides and organic carbonates, as well as adjusting processing parameters like deposition temperature and plasma power during PECVD. These parameter optimizations enable the electrolyte to achieve both high stability and high ionic conductivity (>10^-5 S/cm) by fine-tuning the material's structural and chemical properties.
2Ease of manufacture
If polymer electrolytes are used, then ease of manufacture is improved, but reliability deteriorates (formation of crystalline zones capable of trapping Li+)
Solution Approach 1:
The patent applies phase transitions by controlling the amorphous-to-crystalline transition of the electrolyte material. By maintaining the electrolyte in an amorphous phase through controlled deposition and avoiding crystallization, the patent prevents Li+ trapping while preserving the ease of manufacturing associated with polymer electrolytes. The glass transition temperature management ensures the electrolyte remains in the desired amorphous state.
Solution Approach 2:
The patent replaces traditional mechanical mixing and hot-pressing methods used for polymer electrolytes with plasma-enhanced chemical vapor deposition (PECVD). This substitution enables precise control over the electrolyte's microstructure, ensuring an amorphous, homogeneous structure without crystalline zones, while maintaining manufacturing efficiency through a single-step deposition process.
3Reliability
If conventional glass electrolytes are used, then stability is improved, but manufacturing precision deteriorates (does not allow production of deposits conforming to substrates)
Solution Approach 1:
The patent applies pneumatic principles through the use of plasma-enhanced chemical vapor deposition (PECVD), where gaseous precursors are delivered and activated in a controlled plasma environment. This approach enables conformal deposition on complex substrate geometries, achieving uniform thin films with precise thickness control while maintaining the electrochemical stability of glass electrolytes.
Solution Approach 2:
The patent replaces conventional mechanical sputtering or evaporation methods with plasma-based chemical deposition. This substitution allows for better conformality and thickness uniformity by enabling the precursor gases to penetrate and deposit uniformly across the entire substrate surface, including recessed areas, while maintaining the stability characteristics of glass electrolytes.
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 new electrolyte achieves improved chemical stability and ionic conductivity, with specific carbon content and hardness levels ensuring both stability and performance, while being compatible with microelectronics manufacturing processes.
Implementation Method 1
The electrolyte is obtained by plasma chemical vapor deposition of a gaseous carbonaceous precursor to which is added a lithiated gaseous precursor and a neutral carrier gas such as helium
Implementation Method 2
Ionic conductivity is commonly attributed to the mobility of Li+... having an ionic conductivity greater than 1 x 10^-6
Data Source
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AI summary
Electrolyte comprises solid amorphous lithium-silicon containing compounds (I). Electrolyte comprises solid amorphous lithium-silicon containing compounds of formula (Si vO wC xH yLi z) (I). Either v : 0-40, preferably 0-15; and w : 5-50, preferably 15-30; and x : greater than 12, preferably 20-40; and y : 10-40, preferably 15-30; and z : 1-70, preferably 20-40; or v+w+x+y+z : 95-100%. Independent claims are included for: (1) a process for fabricating the electrolyte comprising plasma chemical vapor deposition of gaseous mixture containing carbon gas precursor, lithium-containing gas precursor and neutral carrier gas such as helium on a support; (2) a solid microbattery comprising the electrolyte; (3) an electrochrome system comprising the electrolyte; and (4) a lithium secondary battery comprising the electrolyte.