Titanium Oxide Nanotube Negative Electrode for High-Capacity Lithium Batteries

Solution Overview

Problem

Current negative electrode materials for lithium secondary batteries, such as graphite, have reached their theoretical capacity limits, and alternatives like lithium titanium oxide and bronze-phase titanium dioxide suffer from poor kinetic properties and short lifespan, necessitating the development of improved negative active materials with enhanced specific capacity and rate capability.

Innovation Solution

A negative active material comprising titanium oxide nanotubes with specific Raman spectrum peaks between 680 cm−1 and 750 cm−1, manufactured through hydrothermal processing and annealing of alkali metal titanate nanotubes, offering a higher specific surface area and improved lithium ion diffusion rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If graphite is used as negative active material, then the battery structure is simple and manufacturing is easy, but the specific capacity has reached theoretical limits and cannot be improved further

Engineering Contradiction:

Improveease of manufactureVSAvoidspecific capacity

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent changes the chemical composition and crystal structure parameters of the negative active material from graphite to titanium oxide with bronze phase structure. This parameter change enables the material to achieve higher specific capacity (170 mAh/g for Li4Ti5O12) while maintaining good manufacturing feasibility through established hydrothermal and annealing processes

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system by combining titanium oxide with bronze phase structure (TiO2-B) and lithium titanium oxide (Li4Ti5O12) in specific ratios. This composite approach leverages the high capacity of bronze phase TiO2 and the stability of Li4Ti5O12 to achieve both improved specific capacity and cycle life

Inventive Principle:

Principle #40Composite materials

2Reliability

If lithium titanium oxide is used to achieve higher voltage and stability, then thermal stability and reversibility are improved, but specific capacity decreases to about 170 mAh/g

Engineering Contradiction:

Improvethermal stabilityVSAvoidspecific capacity

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent creates a composite material system by combining titanium oxide with bronze phase structure (TiO2-B) and lithium titanium oxide (Li4Ti5O12) in specific ratios. This composite approach leverages the high capacity of bronze phase TiO2 and the stability of Li4Ti5O12 to achieve both improved specific capacity and cycle life

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If bronze-phase titanium dioxide is used to increase specific capacity, then theoretical capacity is improved, but kinetic properties and lifespan deteriorate

Engineering Contradiction:

Improvespecific capacityVSAvoidlifespan

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent creates a composite material system by combining titanium oxide with bronze phase structure (TiO2-B) and lithium titanium oxide (Li4Ti5O12) in specific ratios. This composite approach leverages the high capacity of bronze phase TiO2 and the stability of Li4Ti5O12 to achieve both improved specific capacity and cycle life

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the phase composition parameters by controlling the bronze phase TiO2 content within 10-90 wt% and Li4Ti5O12 content within 10-90 wt%. This parameter optimization balances the high capacity of bronze phase with the long cycle life of lithium titanium oxide, achieving both improved specific capacity and lifespan

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

The titanium oxide nanotube-based negative active material enhances the charge and discharge characteristics, specific capacity, and lifespan of lithium secondary batteries, facilitating better commercialization and high-rate discharge capabilities.

Implementation Method 1

hydrothermally contacting a first titanium oxide nanotube and an alkali metal hydroxide to prepare a first microparticle including a cluster of alkali metal titanate nanotubes

Methodology Applied

Scientific EffectHydrothermal processing:

Implementation Method 2

exchanging an alkali metal ion of the first microparticle with a hydrogen ion to prepare a second microparticle i a cluster of hydrogen titanate nanotubes

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Implementation Method 3

annealing the second microparticle to prepare a third microparticle including a cluster of second titanium oxide nanotubes

Methodology Applied

Scientific EffectAnnealing: Annealing

Data Source

PatentUS9972839B2Negative active material, method of preparing the same, negative electrode including the same, and lithium secondary battery including the negative electrode

Publication Date: 2018.05.15 SAMSUNG ELECTRONICS CO LTD

AI summary

A negative active material, a method of preparing the same, and a lithium secondary battery including the negative electrode. The negative active material includes a plurality of titanium oxide nanotubes, wherein the Raman shift of the negative active material includes a characteristic peak located at a Raman shift between about 680 cm−1 and about 750 cm−1.