Organic Sulfur Material via Liquid-Phase Carbonization
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Solution Overview
Problem
Current sulfur-carbon composites for high-capacity lithium-ion batteries face issues with heat resistance and high production costs due to the use of expensive materials like polyacrylonitrile, and the slow reaction rates with solid starting materials, which hinder efficient sulfur incorporation.
Innovation Solution
A method involving the heat treatment of a solution containing polyethylene glycol and a sulfur-containing starting material in an inert atmosphere, allowing for the efficient carbonization and incorporation of sulfur, resulting in an organic sulfur material with high capacity and heat resistance, using a more cost-effective and reactive liquid organic starting material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyacrylonitrile (PAN) is used as a starting material to produce sulfur-carbon composites, then the composites exhibit excellent capacity and cycle characteristics, but the production cost increases significantly
Solution Approach 1:
The patent replaces expensive polyacrylonitrile (PAN) with inexpensive polyethylene glycol (PEG) as the carbon source material. PEG is a low-cost, readily available polymer that serves the same functional purpose of providing carbon for the sulfur-carbon composite structure, thereby dramatically reducing production costs while maintaining acceptable battery performance
Solution Approach 2:
The patent changes the chemical composition and molecular structure parameters of the starting material from PAN to PEG. This parameter change alters the reaction characteristics and product properties, achieving a balance between cost-effectiveness and battery performance by selecting PEG with specific molecular weight and functional groups
2Stability of the object's composition
If solid starting materials are used in the reaction, then the material structure is maintained, but the reaction rate decreases significantly
Solution Approach 1:
The patent utilizes the phase transition of polyethylene glycol from solid to liquid state upon heating. By conducting the reaction in the liquid phase, the patent achieves significantly enhanced reaction kinetics and sulfur incorporation efficiency compared to solid-state reactions, while the resulting carbonized structure provides the necessary material stability
Solution Approach 2:
The patent employs a solution-based liquid-phase reaction system where PEG dissolves in a solvent, creating a homogeneous liquid mixture that facilitates rapid diffusion and reaction with sulfur. This liquid-phase approach dramatically accelerates the reaction rate compared to solid-state processing
3Quantity of substance
If elemental sulfur is used in battery systems with organic electrolyte, then the theoretical capacity is high, but capacity reduction occurs due to lithium polysulfide dissolution
Solution Approach 1:
The patent creates a sulfur-carbon composite material where sulfur is embedded within a carbon matrix derived from polyethylene glycol. This composite structure physically confines sulfur and its reaction products, preventing polysulfide dissolution into the electrolyte while maintaining high capacity. The carbon matrix acts as a host structure that stabilizes sulfur
Solution Approach 2:
The carbonized PEG structure forms a porous network that accommodates sulfur and provides pathways for ion transport. The porous structure increases the surface area and provides numerous sites for sulfur anchoring, enhancing both capacity and stability by preventing polysulfide aggregation and dissolution
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 organic sulfur material exhibits excellent charge-discharge characteristics and heat resistance, with sulfur trapped within carbon pores, preventing dissolution into the electrolyte, and is produced at a lower cost compared to traditional methods, enhancing battery performance and efficiency.
Implementation Method 1
the liquid organic substance undergoes carbonization and efficiently incorporates sulfur
Implementation Method 2
subjecting a solution containing polyethylene glycol or a derivative thereof and a sulfur-containing starting material to heat treatment in an inert atmosphere
Data Source
AI summary
An organic sulfur material comprising carbon, hydrogen, oxygen, and sulfur as constituent elements, and having peaks in the vicinity of 482 cm−1, 846 cm−1, 1066 cm−1, 1279 cm−1, and 1442 cm−1 in a Raman spectrum detected by Raman spectroscopy, the peak in the vicinity of 1442 cm−1 being most intense, has a high capacity and high heat resistance, although a liquid organic starting material is used.