Protected Electrode Layers for PTFE Binder Side-Reaction Control

Resolve Bottlenecks,
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) binder material and anode materials during lithium ion insertion.

Innovation Solution

The use of electrodes with first and second protective polymeric layers coated over electroactive material particles and binder material fibers, respectively, to prevent side reactions and enhance performance, where the layers are formed using a precursor polymeric solution containing monomers like ethylene oxide, vinylidene fluoride, and acrylonitrile, and are applied through heating and pressing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If polytetrafluoroethylene (PTFE) binder material is used to hold extra active materials and enable thicker electrodes, then electrode thickness and capacity are improved, but undesirable side reactions occur between the binder material and anode material during lithium ion insertion, resulting in reduced anodic Columbic efficiency and mechanical degradation

Engineering Contradiction:

Improveelectrode thickness and active material capacityVSAvoidanodic Columbic efficiency and mechanical properties

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A protective layer comprising a polymer coating is applied to the PTFE binder material fibers. This protective layer acts as an intermediary barrier between the PTFE binder and the anode material particles, preventing direct contact and undesirable side reactions during lithium ion insertion, thereby maintaining both the binding function and the electrochemical performance

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective layer is selectively applied only to the binder material fibers where it is needed to prevent side reactions, while leaving the anode material particles and other electrode components unaffected. This localized application preserves the overall electrode structure and function while addressing the specific problem at the binder-material interface

Inventive Principle:

Principle #3Local quality

2Reliability

If protective layers are coated over binder material fibers to prevent side reactions, then anodic Columbic efficiency and mechanical stability are improved, but electrode manufacturing complexity increases

Engineering Contradiction:

Improveanodic Columbic efficiency and mechanical stabilityVSAvoidelectrode manufacturing process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective layer formation process is integrated with the existing electrode manufacturing workflow. The polymer coating is applied to binder fibers during the electrode assembly process, combining the protective layer formation with the electrode fabrication steps rather than requiring separate, additional processing stages

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The protective layer is formed by controlling polymerization parameters such as monomer concentration, initiator type, and reaction conditions to achieve the desired coating thickness and properties. By optimizing these parameters, the protective layer can be formed with controlled characteristics that prevent side reactions while maintaining electrode performance

Inventive Principle:

Principle #35Parameter changes

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 protective layers improve the Columbic efficiency and mechanical stability of the electrodes, reducing side reactions and enhancing the overall performance of lithium-ion batteries.

Implementation Method 1

The precursor polymeric solution may include a polymer precursor selected from the group consisting of: ethylene oxide (EO), vinylidene fluoride (VDF), vinylidene fluoride-hexafluoropropylene (VDF-HFP), propylene oxide (PO), acrylonitrile (AN), methacrylonitrile (MAN) ethylene glycol (EG), trimethylene carbonate (TMC), methyl methacrylate (MMA), oligomers of the same, and combinations thereof

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS20240030552A1Protective layers separating electroactive materials and binder materials in electrode and methods of forming the same

Publication Date: 2024.01.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

An electrode assembly for an electrochemical cell that cycles lithium ions is provided. The electrode assembly includes one or more electroactive material layers including a plurality of electroactive material particles and a plurality of binder material fibers dispersed with the electroactive material particles. At least one electroactive material particle of the plurality may have a first protective layer coated thereon, and at least one binder material fiber of the plurality may have a second protective layer coated thereon. The first and second protective layers may be the same or different. The binder material fibers can include polytetrafluoroethylene (PTFE).