Granular Lignin-Carbon Composite for Shape-Stable Thermal Conversion
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Solution Overview
Problem
Existing methods for producing carbon enriched materials from lignin face challenges such as lignin's thermoplastic behavior during thermal conversion, leading to melting, swelling, and deformation, which limits processability and scalability.
Innovation Solution
A method involving the agglomeration of lignin with a carbon additive to form a thermally stabilized agglomerated lignin-carbon composite material, which is then heat-treated to produce a granular carbon-carbon composite material, thereby avoiding melting and swelling and improving mechanical and thermal processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lignin powder is directly used as precursor for carbon enriched material, then renewable carbon source utilization is achieved, but thermoplastic behavior causes melting, swelling and deformation during thermal conversion
Solution Approach 1:
The patent combines lignin with inorganic additives (metal salts such as aluminum sulfate, calcium chloride, or magnesium sulfate) to create a composite material system. The inorganic components form a rigid framework that counteracts the thermoplastic behavior of lignin during thermal conversion, enabling shape retention while utilizing renewable carbon source. The composite structure allows the lignin to contribute carbon while the inorganic additives provide structural stability.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the lignin system by introducing inorganic additives that change the thermal behavior characteristics. The metal salts alter the melting point, viscosity, and swelling properties of the lignin matrix during thermal processing, transforming it from a thermoplastic material to a thermally stable composite that maintains dimensional integrity.
2Shape
If inorganic additives are used to reduce melting and swelling behavior of lignin, then shape stability is improved, but catalytic activation of carbon structure occurs and post-purification is required
Solution Approach 1:
The patent optimizes the type and concentration of inorganic additives to achieve shape stability while minimizing catalytic effects. By carefully selecting metal salts and controlling their amounts, the patent finds a parameter window where shape stability is maintained but unwanted catalytic activation is reduced to acceptable levels.
Solution Approach 2:
The patent acknowledges that some post-purification may be necessary to remove residual metal salts, but frames this as an acceptable trade-off for achieving shape stability. The process design considers the purification step as part of the overall manufacturing workflow, potentially using methods like washing or chelation to remove additives.
3Productivity
If lignin undergoes thermal conversion to carbon enriched material, then carbon material production is achieved, but aggressive swelling and foaming severely limits processability and scalability
Solution Approach 1:
The patent creates a lignin-inorganic additive composite that suppresses the aggressive swelling and foaming behavior of pure lignin during thermal conversion. The inorganic framework acts as a structural constraint that controls volume expansion, transforming the process from uncontrolled foaming to controlled densification, thereby improving processability and enabling industrial-scale production.
Solution Approach 2:
The patent modifies the thermal conversion parameters by introducing inorganic additives that change the swelling kinetics and foaming behavior. The additives alter the viscosity-temperature relationship and gas evolution characteristics, enabling controlled thermal processing at industrial scales with predictable material behavior.
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 method allows for the production of carbon enriched materials from lignin with retained shape and dimension, enhancing processability and scalability, and producing a material suitable for use in negative electrodes of non-aqueous secondary batteries.
Implementation Method 1
heating the agglomerated lignin-carbon composite material to a temperature in the range of from 140 to 250° C. for a period of at least 30 minutes to obtain a thermally stabilized agglomerated lignin-carbon composite material
Implementation Method 2
subjecting the thermally stabilized agglomerated lignin-carbon composite material to heat treatment at one or more temperatures in the range of from 300° C. to 1500° C., wherein the heat treatment is carried out for a total time in the range of from 30 minutes to 10 hours, to obtain a granular carbon-carbon composite material
Data Source
AI summary
The present invention is directed to a method for producing a thermally stabilized agglomerated lignin-carbon composite material. The method involves the steps of providing an agglomerated lignin-carbon composite material comprising lignin and at least one carbon additive; and heating the agglomerated lignin-carbon composite material to obtain the thermally stabilized agglomerated lignin-carbon composite material. The invention is also directed to a granular carbon-carbon composite material obtained by heat treatment of the thermally stabilized agglomerated lignin-carbon composite material.