Polymer-Shell PTFE Binders for Li-Ion Electrode Side-Reaction Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face issues with reduced anodic Columbic efficiency and mechanical degradation due to undesirable side reactions between polytetrafluoroethylene (PTFE) binders and certain battery materials during lithium ion insertion processes.
Innovation Solution
Development of modified polytetrafluoroethylene (PTFE) binders with a polymeric shell coating on PTFE nanoparticles, including polymers like polyethylene oxide and humidity-tolerant lithium salts, to reduce side reactions and enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If polytetrafluoroethylene (PTFE) binder is used to hold extra active materials and permit forming thicker electrodes, then electrode thickness and active material capacity are improved, but undesirable side reactions occur during lithium ion insertion processes resulting in reduced anodic Columbic efficiency and degradation of mechanical properties
Solution Approach 1:
A polymer coating layer is applied to the PTFE binder particles to act as an intermediary between the PTFE and the active materials. This coating layer prevents direct contact and harmful interactions between PTFE and active materials during lithium ion insertion, while still allowing the PTFE to fulfill its binding function. The coating serves as a protective mediator that eliminates side reactions and improves anodic Columbic efficiency.
2Quantity of substance
If polytetrafluoroethylene (PTFE) binder is used to hold extra active materials and permit forming thicker electrodes, then electrode thickness and active material capacity are improved, but mechanical properties degrade due to side reactions
Solution Approach 1:
The polymer coating acts as a protective intermediary that prevents direct interaction between PTFE and active materials, thereby preventing mechanical degradation caused by side reactions. The coating layer maintains the structural integrity of the electrode while allowing the PTFE to provide binding functionality.
Solution Approach 2:
The invention creates a composite structure where PTFE particles are coated with a polymer layer. This composite material combines the binding properties of PTFE with the protective and mechanically stable properties of the polymer coating, resulting in improved mechanical properties while maintaining electrode thickness and active material capacity.
3Stability of the object's composition
If standard PTFE binder is used, then electrode structure is maintained, but performance degrades under varying humidity conditions
Solution Approach 1:
The polymer coating serves as a protective intermediary that shields the PTFE binder from humidity-related degradation. This coating layer prevents direct exposure of the PTFE to moisture in the environment, thereby maintaining both the structural stability and performance reliability under varying humidity conditions.
Solution Approach 2:
The invention modifies the PTFE binder by adding a polymer coating, which changes the chemical and physical parameters of the binder material. This parameter change makes the binder more resistant to humidity, improving performance reliability while maintaining structural stability.
Data Source
AI summary
The present disclosure provides a modified binder for use in an electrochemical cell that cycles lithium ions. The modified binder includes one or more agglomerates of polytetrafluoroethylene nanoparticles, where each of the polytetrafluoroethylene nanoparticles includes a polytetrafluoroethylene core and a polymeric shell that is disposed on exposed surfaces of the core. The polymeric shell can include a polymer selected from the group consisting of: polyethylene oxide, polyglycidyl methacrylate, polyvinylidene difluoride, fluoride-hexafluoropropylene, polypropylene oxide, polyacrylonitrile, polymethacrylonitrile, polymethyl methacrylate, derivatives and co-polymers, and combinations thereof, and in certain instances, also a humidity tolerant lithium salt. The polytetrafluoroethylene core can have a first particle size ranging from about 10 nanometers to about 500 nanometers, the polymeric shell can have an average thickness ranging from about 10 nanometers to about 1,000 nanometers, and each of the one or more agglomerates can have an average size ranging from about 100 micrometers about 1,000 micrometers.