Sodium-Ion Battery Polymer Protective Layer for Dendrite Inhibition

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Solution Overview

Problem

Sodium-ion batteries face challenges due to their lower energy density compared to lithium-ion batteries, primarily attributed to the larger ion mass and radius of sodium, which hinders their development.

Innovation Solution

A sodium-ion battery design that includes a positive electrode sheet, a separator, and a negative electrode current collector with a protective layer made of polymer material on the negative electrode current collector, allowing sodium-ions to pass freely and inhibiting the growth of sodium dendrites.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective layer is added to the negative electrode current collector, then cycle performance is improved and sodium dendrite growth is inhibited, but device complexity increases

Engineering Contradiction:

Improvecycle performanceVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective layer is pre-formed on the negative electrode current collector before battery assembly. This preliminary action prevents sodium dendrite growth from the outset, improving cycle performance without requiring complex control mechanisms during operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective layer acts as an intermediary between the negative electrode current collector and the sodium ions. It mediates the interaction by allowing ion passage while preventing dendrite formation, thus improving reliability without significantly increasing overall device complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a protective layer is added to the negative electrode current collector, then sodium dendrite growth is inhibited, but manufacturing complexity increases

Engineering Contradiction:

Improvedendrite inhibitionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The protective layer is prepared in advance through coating and drying processes, simplifying the manufacturing workflow. This preliminary preparation avoids complex in-situ formation steps and integrates seamlessly into existing battery manufacturing lines.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective layer uses inexpensive polymer materials that can be applied as a thin, disposable coating. This approach avoids the need for expensive, complex dendrite prevention mechanisms while maintaining effective protection.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If polymer material is used for the protective layer, then costs are reduced and sodium-ion passage is enabled, but energy density may be affected

Engineering Contradiction:

Improvematerial costVSAvoidenergy density

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The protective layer is designed as a thin polymer film that provides necessary protection while minimizing mass addition. This thin-film approach allows inexpensive materials to be used without significantly impacting the battery's energy density.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The thickness and composition of the polymer layer are optimized to balance cost, ion conductivity, and mass. By adjusting these parameters, the protective layer achieves effective dendrite prevention while minimizing the impact on energy density.

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

This design enhances the cycle performance of sodium-ion batteries, reduces the need for additional negative electrode active material layers, lowers costs, and improves energy density.

Implementation Method 1

a surface of the negative electrode current collector is provided with a protective layer capable of allowing sodium-ions to pass freely

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

inhibiting the growth of sodium dendrites

Methodology Applied

Scientific EffectPhysical barrier protection: Physical Containment

Data Source

PatentUS20250125374A1Sodium-ion battery and electrical apparatus comprising the same

Publication Date: 2025.04.17 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

The present application relates to a sodium-ion battery and an electrical apparatus including the same. The sodium-ion battery includes a positive electrode sheet, a separator, and a negative electrode current collector, wherein the separator is disposed between the positive electrode sheet and the negative electrode current collector, a surface of the negative electrode current collector is provided with a protective layer capable of allowing sodium-ions to pass freely, a material of the protective layer mainly includes a polymer material, there is an accommodation area between the protective layer and the negative electrode current collector, and the accommodation area has a sodium metal layer formed on the surface of the negative electrode current collector. The sodium-ion battery can effectively improve the inhibition of sodium dendrites, reduce side reactions between sodium metal and an electrolyte solution, and improve the cycle performance of the sodium-ion battery.