Composite Anode Active Material for Lithium Battery

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Solution Overview

Problem

Lithium batteries using carbon-based anode active materials face limitations in capacity and cycle life due to irreversible charge/discharge reactions and structural degradation, while metal-based materials suffer from rapid volume changes leading to conductivity loss and detachment from the current collector.

Innovation Solution

A composite anode active material comprising a combination of carbon-based, metal-based, and polymer particles, where the polymer particles act as cushioning agents to stabilize the structure during charge/discharge cycles and metal particles enhance conductivity, thereby maintaining capacity and improving cycle life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If metal-based anode active materials are used to increase capacity, then the battery capacity and energy density are improved, but the cycle life performance deteriorates due to volume changes during charge/discharge cycles

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle life performance

Core Design Contradiction:

Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The patent embeds metal-based anode active material particles inside porous carbon particles, creating a nested structure where the metal is contained within the carbon matrix. This nesting approach allows the metal to provide high capacity while the carbon shell constrains volume expansion and maintains structural integrity over cycles.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent creates a composite anode material combining metal-based active materials with carbon-based materials. The composite structure leverages the high capacity of metal materials while the carbon component provides structural stability and conductivity, resolving the contradiction between capacity and cycle life.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If inorganic materials such as silicon or tin are used as anode active materials, then the theoretical capacity is increased, but the conductivity degrades and the active material detaches from the current collector due to volume expansion

Engineering Contradiction:

Improvetheoretical capacityVSAvoidconductivity and structural stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies different materials with different properties to different parts of the anode structure: metal-based materials are placed in the core where they provide capacity, while carbon materials form the outer shell where they provide conductivity and structural stability. This local differentiation resolves the contradiction between capacity and reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses a porous carbon shell as a flexible constraint around the metal particles. This carbon shell accommodates volume changes of the metal during charge/discharge while maintaining structural integrity and electrical conductivity, preventing detachment from the current collector.

Inventive Principle:

Principle #30Flexible shells and thin films

3Duration of action of stationary object

If carbon-based anode active materials are used, then the cycle life performance is improved, but the capacity is limited due to irreversible charge/discharge reactions

Engineering Contradiction:

Improvecycle life performanceVSAvoidbattery capacity

Core Design Contradiction:

Duration of action of stationary objectVSQuantity of substance

Solution Approach 1:

The patent merges the advantages of carbon-based materials (cycle life, structural stability) with metal-based materials (high capacity) into a single composite anode structure. The carbon matrix provides the stability needed for long cycle life while the embedded metal particles contribute high capacity, achieving both goals simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

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 composite anode active material achieves a large capacity, high initial efficiency, and extended cycle life by stabilizing the structure and increasing conductivity, addressing the limitations of both carbon-based and metal-based materials.

Implementation Method 1

polymer particles that are introduced into the composite anode active material function as cushioning agents which buffer against stress with respect to a change in the volume of the composite anode active material during charge/discharge cycles

Methodology Applied

Scientific EffectCushioning effect: Elasticity

Implementation Method 2

metal particles are uniformly dispersed in the composite anode active material, thereby increasing the conductivity thereof

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

greater intercalation and deintercalation capability with respect to lithium ions compared to anode active materials using carbon-based materials

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Data Source

PatentUS8906554B2Composite anode active material, anode including the same and lithium battery using the anode

Publication Date: 2014.12.09 SAMSUNG SDI CO LTD

AI summary

A composite anode active material includes a composite of a carbon-based anode active material, a metal-based anode active material and polymer particles. By increasing the conductivity of the composite anode active material, a lithium battery having a large capacity, high initial efficiency, high rate capability and improved cycle life performance can be obtained. An anode includes the composite anode active material and a lithium battery includes the anode.