Silicon Negative Electrode Polymer Network for Cycle Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The performance of lithium-ion batteries is limited by the negative electrode materials, particularly silicon-based electrodes, which experience large volume expansion during cycling, leading to destruction of the conductive network and rapid deterioration due to lithium alloying and SEI film consumption.

Innovation Solution

A high elastic and extensible polymer is introduced in the negative electrode piece through in-situ polymerization, forming a conductive network that reduces side reactions and enhances lithium ion transmission, using polymers such as polyphenylene oxide polyacrylate, polyethylene glycol polymethylmethacrylate, polycarbonate polyacrylate, polypropylene glycol polymethylacrylate, and polysiloxane polymethylmethacrylate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If silicon negative electrode is used to achieve high energy density, then capacity per gram is improved, but volume expansion during cycling destroys conductive network and causes rapid deterioration

Engineering Contradiction:

Improvecapacity per gramVSAvoidconductive network stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a flexible polymer coating layer on the silicon negative electrode surface. This polymer film acts as a protective shell that can accommodate volume expansion while maintaining structural integrity, preventing conductive network destruction and SEI film consumption during cycling.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure combining silicon active material with polymer materials. This composite approach allows the silicon to provide high capacity while the polymer provides mechanical stability and flexibility to handle volume changes, resolving the contradiction between high capacity and structural stability.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If silicon negative electrode is used to achieve high energy density, then capacity per gram is improved, but side reactions increase due to SEI film continuous consumption

Engineering Contradiction:

Improvecapacity per gramVSAvoidSEI film consumption

Core Design Contradiction:

Quantity of substanceVSLoss of energy

Solution Approach 1:

The polymer coating serves as a stable film that prevents continuous SEI formation and consumption. It provides a protective barrier that reduces side reactions between electrolyte and silicon while accommodating volume expansion, thereby reducing energy loss.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent converts the harmful volume expansion effect into a beneficial feature by using the polymer's flexibility to accommodate expansion without failure. The expansion that would normally destroy the structure is instead used to demonstrate the polymer's protective capability, reducing side reactions.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If carbon material negative electrode is used to ensure structural stability, then conductive network is maintained, but energy density is reduced

Engineering Contradiction:

Improveconductive network stabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent creates a composite where silicon provides high capacity and polymer provides structural stability. This composite structure achieves both high energy density from silicon and maintained conductive network stability from the polymer, overcoming the limitation of pure carbon electrodes.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by introducing polymers with specific mechanical properties (flexibility, elasticity) that can accommodate silicon's volume expansion. This parameter change allows the system to achieve high energy density while maintaining structural stability during cycling.

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 polymer improves the conductive channels within the electrode, reducing internal resistance and battery degradation, thereby enhancing the cycling performance and capacity retention of lithium-ion batteries.

Implementation Method 1

with the intercalation and deintercalation of lithium ions, the negative electrode piece has defects, such as, a large volume expansion

Methodology Applied

Scientific EffectVolume expansion:

Implementation Method 2

improve lithium conductive channels inside the electrode piece

Methodology Applied

Scientific EffectLithium ion transmission:

Data Source

PatentUS12592388B2Negative electrode piece and secondary battery including same

Publication Date: 2026.03.31 ZHUHAI COSMX BATTERY CO LTD

AI summary

A negative electrode piece and a secondary battery including the same. A type of polymer different from that in the prior art is selected as a component in the negative electrode piece, the polymer has high elasticity, high extensibility, can replace the polymer in the existing negative electrode piece, and can effectively improve and enhance the transmission performance of lithium ions and reduce the internal resistance of the lithium-ion battery. At the same time, it can effectively reduce side reactions caused by the expansion of the negative electrode piece, improve lithium conductive channels inside the negative electrode piece, and improve battery performance of the negative electrode piece during the battery cycling.