Negative Electrode Plate Coating to Suppress Side Reactions and Gas

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Solution Overview

Problem

Existing electrochemical devices experience rapid decay in cycle life due to side reactions between the electrolyte and negative electrode interface, leading to gas production, irreversible capacity increase, and safety concerns such as short circuits, primarily due to poor transmission performance of electrolyte cations and metal dendrite formation.

Innovation Solution

A negative electrode plate is developed with an inorganic dielectric layer between the negative active material and the separator, featuring a compact density, porosity, and high wetting velocity, which stabilizes the electrode interface, reduces side reactions, and inhibits gas production, thereby enhancing safety and cycle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrolyte is used in existing electrochemical devices, then electrochemical energy storage is achieved, but side reactions occur at the negative electrode interface causing gas production and rapid cycle life decay

Engineering Contradiction:

Improvecycle lifeVSAvoidside reactions and gas production

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

An inorganic dielectric layer is introduced as an intermediary between the negative electrode and electrolyte. This layer acts as a mediator that prevents direct contact between the electrolyte and negative electrode active material, thereby eliminating side reactions and gas production while maintaining electrochemical functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The inorganic dielectric layer is applied in advance to the negative electrode surface before electrolyte contact. This preliminary protective action prevents harmful side reactions from occurring by blocking the interface where these reactions would otherwise take place during cycling.

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If inorganic dielectric layer is added to prevent side reactions, then safety and cycle performance improve, but device structure becomes more complex

Engineering Contradiction:

Improvesafety performanceVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The inorganic dielectric layer is implemented as a thin film coating on the negative electrode surface. This thin film approach provides the necessary protective function while minimizing structural complexity and maintaining compatibility with existing electrode manufacturing processes.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If inorganic dielectric layer is applied to reduce side reactions, then irreversible capacity increases, but manufacturing process becomes more complex

Engineering Contradiction:

Improvecycle performanceVSAvoidpreparation process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical coating methods with vapor deposition technology to apply the inorganic dielectric layer. This substitution enables precise thickness control, uniform coverage, and integration with existing electrode manufacturing processes, thereby reducing manufacturing complexity despite the additional functional layer.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution significantly improves the safety and cycle performance of electrochemical devices by reducing irreversible capacity, preventing short circuits, and maintaining high temperature performance, while also inhibiting Direct Current Resistance growth, thus enhancing overall electrochemical performance.

Implementation Method 1

an inorganic dielectric layer consisting of an inorganic dielectric material disposed on the first surface of the negative active material layer

Methodology Applied

Scientific EffectDielectric layer protection: Dielectric

Implementation Method 2

depositing an inorganic dielectric material on a surface of the negative active material layer facing away from the negative current collector by vapor deposition

Methodology Applied

Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentUS11901560B2Negative electrode plate, preparation method thereof and electrochemical device

Publication Date: 2024.02.13 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

The invention refers to negative electrode plate, preparation method thereof and electrochemical device. The negative electrode plate comprises: a negative current collector, a negative active material layer, and an inorganic dielectric layer which are provided in a stacked manner; the negative active material layer comprises opposite first surface and second surface, wherein the first surface is disposed away from the negative current collector; the inorganic dielectric layer is disposed on the first surface of the negative active material layer and consists of an inorganic dielectric material. The negative electrode plate provided by the application is useful in an electrochemical device, and can result in an electrochemical device having simultaneously excellent safety performance and cycle performance.