Ultrapure Synthetic Carbon for High-Voltage EDLC Stability
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Solution Overview
Problem
Existing carbon materials used in electric double-layer capacitors (EDLCs) and batteries suffer from decreased performance at high-temperature, high-voltage operation and upon repeated charge/discharge cycles due to electrolyte impurities and impurities in the carbon electrodes, leading to breakdown at the electrolyte/electrode interface, and there is a lack of commercially available high-purity carbon materials with both high surface area and porosity.
Innovation Solution
Development of ultrapure synthetic amorphous carbon materials with a total impurity content of less than 500 ppm, produced through a sol-gel process involving phenolic compounds and aldehydes co-polymerized under acidic conditions with a volatile basic catalyst, followed by freeze drying and activation, resulting in high surface area and porosity without chemical activation impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional pyrolysis or chemical activation methods are used to produce high surface area activated carbon, then surface area and porosity are achieved, but impurity content (ash, metals) increases to 1% or higher
Solution Approach 1:
The invention changes the fundamental parameters of the carbonization process by using a synthetic polymer precursor with controlled composition and structure, rather than natural precursors. This allows precise control over impurity levels while maintaining high surface area through controlled pyrolysis conditions
Solution Approach 2:
The invention extracts and eliminates impurity sources by using a synthetic polymer precursor that can be purified before carbonization, rather than starting with impure natural materials. The process removes the need for chemical activation steps that introduce metal impurities
2Area of stationary object
If chemical activation with acids, bases or salts is used to produce activated carbon, then surface area and porosity are enhanced, but residual process impurities (metals) increase
Solution Approach 1:
The invention converts the potential harm of chemical activation by replacing it with a physical activation approach using controlled pyrolysis of synthetic polymers. This eliminates metal impurity introduction while achieving the desired activated carbon structure through thermal processing alone
Solution Approach 2:
The invention replaces chemical activation mechanisms (acids, bases, salts) with thermal processing mechanisms. The activation is achieved through controlled pyrolysis conditions rather than chemical reactions, eliminating residual chemical impurities
3Ease of manufacture
If existing carbon materials are used in EDLCs and batteries, then devices can be manufactured with current technology, but performance decreases at high temperature, high voltage and upon aging due to impurities
Solution Approach 1:
The invention performs preliminary purification of the carbon material by using a synthetic polymer precursor that is purified before carbonization. This preliminary action prevents impurity formation rather than attempting to remove them later, ensuring high reliability from the start
Solution Approach 2:
The invention uses a composite approach by combining synthetic polymer precursors with controlled composition to create carbon materials with optimized properties. The synthetic nature allows precise control over the carbon structure and impurity levels for enhanced device reliability
4Productivity
If synthetic polymer precursors are pyrolyzed and activated to produce activated carbon, then process yield improves due to intrinsic porosity, but impurity levels remain unsuitable for high performance devices
Solution Approach 1:
The invention changes the purity parameters by using a synthetic polymer with controlled composition and purified precursors. This allows achieving both high yield through intrinsic porosity and high purity through controlled synthesis and purification of the polymer precursor before pyrolysis
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 ultrapure synthetic amorphous carbon materials enable EDLCs and batteries to operate at higher voltages for extended periods at elevated temperatures, offering superior energy storage and distribution capabilities compared to devices using lower purity carbon materials.
Implementation Method 1
reacting one or more polymer precursors comprising phenolic compounds and aldehyde compounds under acidic conditions in the presence of a volatile basic catalyst to obtain an ultrapure polymer gel
Implementation Method 2
freeze drying the ultrapure polymer gel to obtain an ultrapure polymer cryogel
Implementation Method 3
pyrolyzing the ultrapure polymer cryogel to obtain a pyrolyzed ultrapure cryogel
Implementation Method 4
activating the pyrolyzed ultrapure cryogel to obtain ultrapure synthetic activated carbon material
Data Source
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AI summary
The present application is generally directed to ultrapure synthetic carbon materials having both high surface area and high porosity, ultrapure polymer gels and devices containing the same. The disclosed ultrapure synthetic carbon materials find utility in any number of devices, for example, in electric double layer capacitance devices and batteries. Methods for making ultrapure synthetic carbon materials and ultrapure polymer gels are also disclosed.