Electrode Binder Polymer for Faster, Longer-Lasting Li-Ion Cells

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Solution Overview

Problem

The performance of non-aqueous electrochemical devices, such as lithium ion batteries, is impaired due to the binder's ability to reduce the active material's exposed surface area and its low durability, leading to decreased charging-discharging rates and retention of resistance and discharge capacity.

Innovation Solution

Employing a polymer with a specific molecular structure and molecular weight greater than 50,000, containing a unit with a group of 1 to 20 carbon atoms, as a binder to enhance the electrochemical device's performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a binder is used to retain granular active material in the mixture layer, then the active material is effectively retained, but the exposed surface area of the active material is decreased and the charging-discharging rate deteriorates

Engineering Contradiction:

Improveretention of active materialVSAvoidcharging-discharging rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invention changes the molecular weight parameter of the binder polymer to greater than 50,000, which fundamentally alters the binder's properties. This high molecular weight creates a three-dimensional network structure that retains active material effectively while maintaining sufficient porosity and surface area for electrolyte penetration, thus resolving the contradiction between retention and charging-discharging rate

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite polymer structure consisting of a three-dimensional network forming main chain and grafted side chains. This composite structure combines the retention capability of a dense network with the permeability of a porous structure, allowing simultaneous achievement of active material retention and high charging-discharging rate

Inventive Principle:

Principle #40Composite materials

2Reliability

If a binder is used to retain granular active material, then the active material is held in place, but the durability of the device deteriorates due to low binder durability

Engineering Contradiction:

Improveretention of active materialVSAvoiddevice durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The invention changes the molecular weight parameter of the binder to greater than 50,000, which provides exceptional mechanical strength and chemical stability. This high molecular weight polymer resists degradation during charging-discharging cycles, maintaining its binding function over extended periods and thereby improving device durability while retaining active material

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The three-dimensional network structure of the high molecular weight polymer provides a pre-established robust framework that cushions and protects the granular active material from mechanical stress and chemical degradation during cycling, preventing binder failure and extending device lifetime

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS12341197B2Electrochemical device, electrode for electrochemical devices, coating liquid for electrochemical devices, and use of same

Publication Date: 2025.06.24 ZEON CORP

AI summary

An electrochemical device, which is a non-aqueous electrochemical device, comprising a polymer (P) enclosed in an inside of the electrochemical device, wherein the polymer (P) is a polymer having a molecular structure containing a unit (P) represented by the following formula (P), the polymer (P) having a weight-average molecular weight of greater than 50,000, as well as an electrode for an electrochemical device, a coating liquid for an electrochemical device, an insulating layer for an electrochemical device, an undercoat layer for an electrochemical device, and an electrolytic solution for an electrochemical device including the polymer (P) and other ingredients:in the formula (P), RP is a group of 1 to 20 carbon atoms.