Multi-Layered Lithium Titanium Oxide Carbonaceous Battery Electrode

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Lithium ion batteries with carbonaceous negative electrodes suffer from poor high-rate discharge-charge performance, safety issues due to lithium dendrite formation, and low capacity and voltage, despite attempts to improve conductive performance with lithium titanium oxide compounds.

Innovation Solution

A negative electrode with a multi-layered structure, where the carbonaceous material has a higher total weight percentage than lithium titanium oxide compound, with the carbonaceous material content lower in the outermost layer and higher in other layers, enhancing both capacity and voltage while maintaining safety and cycle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If carbonaceous material is used as negative electrode material, then lithium ion storage capacity is improved, but high-rate discharge-charge performance deteriorates due to low lithium ion diffusion rate and lithium dendrite formation

Engineering Contradiction:
Improvelithium ion storage capacityVSAvoidhigh-rate discharge-charge performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent uses a composite negative electrode material consisting of lithium titanium oxide compound (providing high lithium ion diffusion rate and safety) and carbonaceous material (providing high lithium ion storage capacity). This composite structure allows the electrode to simultaneously achieve high capacity and excellent high-rate discharge-charge performance by combining the advantages of both materials while mitigating their individual disadvantages.

Inventive Principle:
Principle #40Composite materials

2Speed

If lithium titanium oxide compound is used as negative electrode material, then lithium ion diffusion rate is improved, but electronic conduction performance deteriorates

Engineering Contradiction:
Improvelithium ion diffusion rateVSAvoidelectronic conduction performance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent creates a composite material where lithium titanium oxide compound provides high lithium ion diffusion rate while carbonaceous material provides electronic conduction. The synergistic combination allows both functions to be performed simultaneously, resolving the contradiction between fast ion transport and electronic conductivity.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If carbonaceous material content is increased to improve capacity, then voltage deteriorates

Engineering Contradiction:
ImprovecapacityVSAvoidvoltage
Core Design Contradiction:
Quantity of substanceVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the compositional parameters of the negative electrode material, specifically controlling the weight ratio of lithium titanium oxide compound to carbonaceous material within 1:9 to 1:4. This parameter optimization allows the electrode to achieve high capacity while maintaining acceptable voltage levels by balancing the contributions of both materials.

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 lithium ion battery achieves a capacity higher than 970mAh and voltage higher than 3.6V, with improved cycle, high-rate discharge-charge, and safety performance compared to conventional batteries.

Implementation Method 1

lithium ions can rapidly carry out intercalation and deintercalation reactions in carbonaceous material

Methodology Applied
Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

lithium ions have high diffusion rate in the material

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP2223368B1Negative electrode for battery and lithium battery using the same
Publication Date: 2011.09.21 BYD CO LTD

AI summary

A negative electrode for battery is provided. The negative electrode comprises a current collector and a negative electrode material coat on the current collector. The negative electrode material comprises carbonaceous material, binder, and lithium titanium oxide compound, wherein in the negative electrode material coat, the carbonaceous material has total weight percentage content higher than that of the lithium titanium oxide compound; and the negative electrode material coat comprises at least two layers; in the outermost layer of the negative electrode material coat, the carbonaceous material has weight percentage content lower than that of the lithium titanium oxide compound; in other layers of the negative electrode material coat, the carbonaceous material has weight percentage content higher than that of the lithium titanium oxide compound. A lithium ion battery using the negative electrode is provided.