Layered TiSi2 Anode with Oxide Coating for Battery Stability

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Solution Overview

Problem

Current lithium-ion battery anode materials face limitations in specific capacity and cycle lifetime due to structural degradation during lithium insertion and extraction, with existing layered structures like graphite and LiCO2 unable to meet growing energy demands, while non-layered materials like Si and Si-alloys suffer from short cycle lifetimes.

Innovation Solution

Development of novel layered structures comprising TiSi2 with a thin oxide coating, allowing for stable lithium ion insertion and extraction with minimal structural change, enhancing charge and discharge performance and maintaining high specific capacity and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high-capacity materials like Si and Si-alloys are used as anodes, then specific capacity is improved, but cycle lifetime deteriorates due to structural degradation

Engineering Contradiction:

Improvespecific capacityVSAvoidcycle lifetime

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies this principle by coating the TiSi2 nanonet with a thin oxide film (such as SiO2, Al2O3, or TiO2) that acts as a protective shell. This thin film coating prevents structural degradation of the high-capacity TiSi2 material during lithium insertion and extraction cycles, thereby maintaining both high specific capacity and long cycle lifetime without sacrificing the capacity benefits of Si-based materials.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a composite structure combining TiSi2 nanonet with a thin oxide coating layer. This composite material integrates the high capacity of TiSi2 with the protective properties of the oxide coating, resolving the contradiction between achieving high specific capacity and maintaining structural stability for long cycle life.

Inventive Principle:

Principle #40Composite materials

2Reliability

If layered structures like graphite and LiCO2 are used as anodes, then cycle lifetime is improved, but specific capacity deteriorates due to chemical limitations

Engineering Contradiction:

Improvecycle lifetimeVSAvoidspecific capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the chemical composition parameter from traditional layered graphite or LiCO2 to TiSi2 with a thin oxide coating. This parameter change enables the material to achieve both long cycle lifetime (through the protective oxide coating) and high specific capacity (through the TiSi2 composition), overcoming the chemical capacity limitations of conventional layered structures.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If TiSi2 is used as anode material, then specific capacity is improved, but structural stability deteriorates without coating

Engineering Contradiction:

Improvespecific capacityVSAvoidstructural stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies this principle by introducing a thin oxide coating film on the TiSi2 nanonet surface. This coating stabilizes the TiSi2 structure during lithium insertion and extraction, preventing structural degradation while maintaining the high capacity characteristics of TiSi2.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The thin oxide coating acts as an intermediary layer between the TiSi2 and the electrolyte, mediating the interaction during lithium insertion and extraction. This intermediary coating protects the TiSi2 from direct contact with the electrolyte, preventing structural instability while allowing lithium ion transport.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 TiSi2 nanonet with a thin oxide coating achieves high specific capacity, long cycle lifetime, and fast charging/discharging rates, addressing the limitations of existing anode materials and enabling next-generation lithium-ion batteries with improved energy density and stability.

Implementation Method 1

allowing for stable lithium ion insertion and extraction with minimal structural change

Methodology Applied

Scientific EffectLithium ion insertion and extraction: Absorption (physical)

Implementation Method 2

The coating stabilizes TiSi2 and significantly improves the charge and discharge performance of TiSi2

Methodology Applied

Scientific EffectSurface stabilization: Surface Tension

Implementation Method 3

the high conductivity of TiSi2 makes it suitable for fast charging/discharging rates

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS9564632B2Layered titanium disilicide, method of preparation and applications thereof

Publication Date: 2017.02.07 BOSTON COLLEGE

AI summary

The invention generally relates to new materials based on C49 titanium disilicide (TiSi2) as a new, layered anode material, within which lithium ions can react with the Si-only layers. Stabilization by a coating a thin layer of oxide on the surface of TiSi2 significantly improves the charge and discharge performance.