Silicon-Carbon Anode Aggregate Structure for Volume Expansion Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium ion batteries face challenges with silicon anode materials due to large volume expansion during lithium intercalation and de-intercalation, leading to pulverization, loss of electrical contact, and reduced cycle stability, making them unsuitable for commercial applications.

Innovation Solution

An anode material comprising an aggregate of active and carbon materials with a target region ratio C ≥15% and porosity ≤10%, where the active material is dispersed with a carbon source and metal oxide, and a conductivity enhancer, processed through heat treatment and densification to inhibit volume expansion and enhance electrochemical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If silicon anode material is used to increase energy density, then the energy density of battery is improved, but the volume expansion rate increases significantly during lithium intercalation and de-intercalation

Engineering Contradiction:

Improveenergy densityVSAvoidvolume expansion rate

Core Design Contradiction:

Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The active material particles are embedded within an aggregate structure composed of carbon material and metal oxide. This nested configuration allows the active material to expand and contract within the constrained aggregate framework, accommodating volume changes while maintaining structural integrity and preventing pulverization during lithium intercalation and de-intercalation cycles.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The anode material employs a composite aggregate structure combining carbon material, metal oxide, and active material. This composite design leverages the mechanical strength and structural stability of carbon and metal oxide to constrain the active material, thereby reducing overall volume expansion while preserving the high energy density benefits of silicon-based anodes.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If silicon anode material undergoes large volume expansion, then the capacity increases, but the active material pulverizes and loses electrical contact during charging and discharging

Engineering Contradiction:

ImprovecapacityVSAvoidelectrical contact stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The aggregate structure is pre-formed with carbon material and metal oxide components arranged in a stable configuration before the active material is introduced. This preliminary structural framework is designed to accommodate and constrain the active material, preventing pulverization and maintaining electrical contact stability throughout charge-discharge cycles.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The carbon material and metal oxide act as intermediary components between the active material and the external environment. These intermediaries provide mechanical support and maintain structural integrity, preventing direct pulverization of the active material and ensuring continuous electrical contact with the current collector during volume expansion and contraction.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If the active material is densely packed to reduce porosity, then the volume expansion is inhibited, but the electrochemical performance may be affected

Engineering Contradiction:

Improvevolume expansionVSAvoidelectrochemical performance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The aggregate structure exhibits local quality variations with different regions serving distinct functions. The carbon material and metal oxide provide structural constraint and mechanical strength in regions where volume expansion occurs, while maintaining appropriate porosity and connectivity in other regions to facilitate electrolyte access and electrochemical reactions, thus balancing volume expansion inhibition with electrochemical performance.

Inventive Principle:

Principle #3Local quality

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 effectively prevents self-agglomeration, maintains electrical contact, and reduces volume expansion, thereby improving the cycle performance and stability of lithium ion batteries while reducing production costs.

Implementation Method 1

the anode material has a large volume expansion rate in the process of lithium de-intercalation and intercalation

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

The aggregate has a small porosity, so that electrolyte is not easy to permeate into the aggregate. The structure of the aggregate facilitates to protect the active material particle therein, which can effectively inhibit volume expansion of the anode material

Methodology Applied

Scientific EffectPhysical containment: Physical Containment

Data Source

PatentUS20240021833A1Anode material and preparation method thereof, and lithium ion battery

Publication Date: 2024.01.18 BTR NEW MATERIAL GRP CO LTD

AI summary

The present application relates to a field of anode material, and an anode material, a preparation method thereof, and a lithium ion battery provided. The anode material includes an aggregate, where the aggregate includes an active material and a carbon material, and the anode material has a porosity of ≤10% and a target region ratio C of ≥15%. The anode material provided is effective in inhibiting volume expansion of anode material and improving cycle performance of battery.