Amorphous Titania Carbon Composite Anode Synthesis
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Solution Overview
Problem
Current methods for synthesizing titanium oxides, particularly at the nanoscale, face challenges in achieving high electrochemical activity and stability, as they often require high-temperature processes that can lead to undesirable side reactions and loss of surface area, limiting their performance in applications like lithium-ion batteries.
Innovation Solution
A method involving the decomposition of a salt comprising 1,4-diazabicyclo[2.2.2]octane (DABCO) and oxalate anion in an oxygen-containing atmosphere at controlled temperatures to produce an amorphous titania/carbon composite, which can then crystallize to anatase, enhancing electrochemical capacity when used as an anode in lithium or lithium ion cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-temperature processes are used to synthesize titanium oxides, then crystalline structure is achieved, but surface area is lost and electrochemical activity decreases
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature (400-900°C) processing to low-temperature (275-400°C) processing. This parameter change allows the formation of titanium oxide with retained surface area and amorphous or nanocrystalline structure, avoiding the sintering and grain growth that occur at higher temperatures. The low-temperature synthesis preserves surface area while achieving sufficient structural organization for electrochemical activity.
Solution Approach 2:
The patent uses a precursor salt containing titanium, oxalate, and DABCO that is pre-synthesized and isolated before the final heating treatment. This preliminary action allows the formation of a well-defined precursor structure that decomposes at low temperature to produce the desired titanium oxide product, avoiding the need for high-temperature direct synthesis that would cause surface area loss.
2Productivity
If nanoscale particle size is achieved, then electrochemical activity increases, but manufacturing complexity increases
Solution Approach 1:
The patent combines multiple functions into a single precursor salt molecule: titanium source, oxalate ligand, and DABCO base are all integrated in one compound. This merging allows the precursor to self-assemble and decompose in a controlled manner during low-temperature heating, producing nanoscale particles without requiring complex multi-step synthesis procedures. The combined precursor simplifies manufacturing while achieving nanoscale dimensions that enhance electrochemical activity.
3Area of stationary object
If amorphous structure is maintained, then surface area is preserved, but electrochemical capacity is limited
Solution Approach 1:
The patent creates a composite material with non-uniform structure: an amorphous or nanocrystalline titanium oxide core with a carbonaceous coating layer on the surface. The local quality varies between core and shell - the core provides high surface area while the carbon coating enhances electrochemical capacity and conductivity. This local differentiation resolves the contradiction between maintaining surface area and improving capacity.
Solution Approach 2:
The patent produces a composite material consisting of titanium oxide combined with carbonaceous material from the decomposed organic components. This composite structure combines the advantages of both components: the titanium oxide provides the desired surface area and structural properties, while the carbon phase enhances electrochemical capacity, conductivity, and stability. The composite nature allows simultaneous achievement of high surface area and high capacity.
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 resulting amorphous titania/carbon composite and anatase materials exhibit higher electrochemical capacity and stability compared to commercial anatase, making them suitable for advanced battery applications and potentially useful in photoelectric cells and catalysis.
Implementation Method 1
When the salt is heated in an oxygen-containing atmosphere (e.g., air) at a temperature of at least about 275° C. and less than 400° C., the salt decomposes to form an amorphous titania/carbon composite material
Implementation Method 2
about 50 to about 60 percent by weight of a carbonaceous material coating the titania
Implementation Method 3
Heating the amorphous titania/carbon composite at a temperature in the range of about 400° C. to about 500° C. causes the titania in the composite sufficient to crystallize to anatase
Data Source
AI summary
An isolated salt comprising a compound of formula (H2X)(TiO(Y)2) or a hydrate thereof, wherein X is 1,4-diazabicyclo[2.2.2]octane (DABCO), and Y is oxalate anion (C2O4−2), when heated in an oxygen-containing atmosphere at a temperature in the range of at least about 275° C. to less than about 400° C., decomposes to form an amorphous titania/carbon composite material comprising about 40 to about 50 percent by weight titania and about 50 to about 60 percent by weight of a carbonaceous material coating the titania. Heating the composite material at a temperature of about 400 to 500° C. crystallizes the titania component to anatase. The titania materials of the invention are useful as components of the cathode or anode of a lithium or lithium ion electrochemical cell.