Silicon Anode Coating with Carbon Nanotubes for Low-Impedance Cycling

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Solution Overview

Problem

Lithium-ion batteries face challenges with high impedance, reduced K value, and poor cycle performance due to volume expansion of silicon-based anode materials and unstable solid electrolyte interfacial (SEI) films.

Innovation Solution

The development of an anode material featuring silicon-based particles with a polymer or amorphous carbon layer containing carbon nanotubes, and incorporating metal elements like Fe, Cu, Zn, Ni, or Co in limited concentrations (<2500 ppm) to enhance conductivity and interfacial stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If silicon-based particles are used as anode material, then capacity is improved, but volume expansion occurs leading to poor cycle performance

Engineering Contradiction:

ImprovecapacityVSAvoidcycle performance

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies nested structure by placing silicon-based particles inside a porous carbon shell, forming a core-shell composite structure. The silicon core provides high capacity while the carbon shell constrains volume expansion, resolving the contradiction between capacity improvement and cycle performance stability.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent uses a porous carbon shell as a flexible constraint structure that accommodates silicon's volume expansion during lithiation/delithiation cycles. The porous structure allows volume change while maintaining structural integrity, preventing particle disintegration and improving cycle performance.

Inventive Principle:

Principle #30Flexible shells and thin films

2Stability of the object's composition

If polymer or amorphous carbon layer is added to silicon-based particles, then interfacial stability is improved, but device complexity increases

Engineering Contradiction:

Improveinterfacial stabilityVSAvoidstructure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent creates a composite material system combining silicon-based particles with polymer or amorphous carbon coating, and further integrates carbon nanotubes into the coating. This composite structure provides interfacial stability between silicon and electrolyte while managing the complexity through material composition rather than structural complexity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The polymer or amorphous carbon layer acts as an intermediary between silicon-based particles and the electrolyte, providing stable interface while allowing lithium ion transport. This intermediary layer resolves the contradiction by decoupling the silicon core from direct contact with electrolyte, reducing structural complexity requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If carbon nanotubes are incorporated into the coating layer, then conductivity is improved, but manufacturing precision requirements increase

Engineering Contradiction:

ImproveconductivityVSAvoidcoating uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs porous carbon coating containing carbon nanotubes, where the porous structure naturally accommodates nanotube distribution without requiring precise positioning. The porosity allows nanotubes to be integrated into the coating matrix, improving conductivity while reducing manufacturing precision requirements for coating uniformity.

Inventive Principle:

Principle #31Porous materials

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 anode material significantly reduces impedance and K value, improves first efficiency, and enhances cycle performance in lithium-ion batteries by stabilizing the carbon nanotubes and minimizing volume expansion.

Implementation Method 1

the polymer layer or the amorphous carbon layer includes carbon nanotubes

Methodology Applied

Scientific EffectConduction (electrical): Conduction (electrical)

Implementation Method 2

A lithium ion battery with an anode active material of the present application has a reduced impedance and K value

Methodology Applied

Scientific EffectImpedance reduction through composite material structure: Composite Materials

Data Source

PatentUS12334547B2Anode material, electrochemical device and electronic device including the same

Publication Date: 2025.06.17 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

An anode material includes silicon-based particles, the silicon-based particles include a silicon-containing substrate, at least a part of the surface of the silicon-containing substrate has: (i) a polymer layer, and/or (ii) an amorphous carbon layer, and the polymer layer or the amorphous carbon layer includes carbon nanotubes, the silicon-based particles include metal elements, the metal elements include Fe, Cu, Zn, Ni, Co, or any combination thereof; wherein the content of the metal elements selected from Fe, Cu, Zn, Ni, Co, or any combination thereof is less than about 2500 ppm based on the total weight of the silicon-based particles. A lithium ion battery with the anode active material has a reduced impedance and K value, and improved first efficiency and cycle performance.