Crosslinked Block Copolymer Coating for Li-Sulfur Polysulfide Trapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-sulfur batteries suffer from life degradation due to the migration of lithium polysulfide from the positive electrode to the negative electrode, leading to irreversible capacity fading and reduced battery life.
Innovation Solution
A block copolymer with pyrene and cationic functional groups is crosslinked to form a sulfur-carbon composite, which is coated on a porous carbon material to capture lithium polysulfide, preventing its migration and maintaining charge/discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium-sulfur batteries use sulfur as positive electrode material, then theoretical energy density increases to 2600 Wh/kg, but lithium polysulfide migrates from positive to negative electrode causing capacity fading and reduced battery life
Solution Approach 1:
A coating layer comprising a crosslinked block copolymer is introduced as an intermediary between the sulfur positive electrode and the electrolyte/negative electrode. This coating layer captures lithium polysulfide through the cationic functional groups in the block copolymer, preventing its migration to the negative electrode while allowing lithium ion transport, thus resolving the contradiction between high energy density and battery life
Solution Approach 2:
The patent uses a composite material system consisting of sulfur embedded in a porous carbon material, with the porous carbon material further coated with a crosslinked block copolymer layer. This multi-component composite structure combines the high capacity of sulfur with the protective and conductive properties of carbon and the polysulfide-capturing functionality of the block copolymer, achieving both high energy density and long battery life
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 sulfur-carbon composite effectively prevents lithium polysulfide migration, maintaining the charge/discharge capacity and improving the battery life of lithium-sulfur batteries.
Implementation Method 1
a second block comprising a second repeating unit having a cationic functional group
Implementation Method 2
a first block comprising a first repeating unit having a pyrene group at a terminal
Implementation Method 3
a coating layer on at least one surface of the porous carbon material, the coating layer comprising the crosslinked block copolymer
Data Source
AI summary
A sulfur-carbon composite of the present disclosure includes a crosslinked block copolymer, and the crosslinked block copolymer is manufactured from a block copolymer comprising a first block including a first repeating unit having a pyrene group at a terminal and a second block including a second repeating unit having a cationic functional group. As the crosslinked block copolymer is coated on the sulfur-carbon composite, it may be possible to prevent migration of lithium polysulfide leaking from a positive electrode of a lithium-sulfur battery to a negative electrode. Accordingly, it may be possible to prevent sulfur particle accumulation on lithium metal surface of the negative electrode, thereby maintaining charge/discharge capacity of the lithium-sulfur battery and improving battery life.