Niobium Composite Oxide with Phosphorus Coating for Battery Anodes

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Solution Overview

Problem

Nonaqueous electrolyte batteries face challenges with high-speed charging and discharging due to dendrite formation on carbon-based negative electrodes, leading to potential short-circuits, and titanium oxide electrodes have lower weight energy density and capacity due to restricted lithium insertion sites.

Innovation Solution

A niobium composite oxide with a monoclinic crystal structure and a phosphorus compound coating on its surface, enhancing lithium ion conductivity and reducing acid sites to prevent electrolyte decomposition, thereby improving charging and discharging efficiency and cycle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a carbon-based negative electrode is used to achieve high energy density, then weight energy density is improved, but dendrites of metal lithium precipitate during high-speed charging and discharging causing short-circuits and safety issues

Engineering Contradiction:

Improveweight energy densityVSAvoiddendrite formation and short-circuit risk

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses a composite negative electrode structure combining carbon material (graphite) and titanium oxide particles. The carbon material provides high energy density while the titanium oxide particles prevent dendrite formation by providing alternative lithium insertion sites, thus resolving the contradiction between energy density and safety

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The titanium oxide particles are distributed locally within the carbon matrix of the negative electrode. This local distribution allows specific regions to provide dendrite prevention functionality while the overall structure maintains high energy density characteristics of carbon-based electrodes

Inventive Principle:

Principle #3Local quality

2Reliability

If a titanium oxide negative electrode is used to prevent dendrites and achieve stable high-speed charging and discharging, then reliability and cycle life are improved, but weight energy density decreases due to lower electric capacity per weight

Engineering Contradiction:

Improvecycle life and stabilityVSAvoidweight energy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The composite negative electrode combines carbon material with high energy density and titanium oxide with high reliability. The synergistic combination allows the electrode to achieve both high weight energy density from the carbon component and excellent cycle stability from the titanium oxide component

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent merges the advantages of carbon-based electrodes (high energy density) and titanium oxide electrodes (dendrite prevention and stability) into a single composite electrode structure, allowing both materials to contribute their respective strengths simultaneously

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If a titanium oxide negative electrode is used to enable high-speed charging and discharging, then charging and discharging rate are improved, but weight energy density decreases due to restricted lithium insertion sites in the crystal structure

Engineering Contradiction:

Improvecharging and discharging rateVSAvoidweight energy density

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The composite structure combines carbon material with fast ion diffusion characteristics and titanium oxide with stable crystal structure. This combination enables the electrode to achieve high charging and discharging rates while maintaining higher weight energy density compared to pure titanium oxide electrodes

Inventive Principle:

Principle #40Composite materials

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 niobium composite oxide with a phosphorus coating achieves higher energy density and stable high-rate performance by reducing dendrite formation and electrolyte decomposition, leading to improved battery lifespan and efficiency.

Implementation Method 1

a phosphorus compound being present on at least a part of the surface of the niobium composite oxide

Methodology Applied

Scientific EffectSurface coating: Coatings

Implementation Method 2

enhancing lithium ion conductivity

Methodology Applied

Scientific EffectIon conductivity: Conduction (electrical)

Implementation Method 3

A niobium composite oxide with a monoclinic crystal structure

Methodology Applied

Scientific EffectCrystal structure: Crystallisation

Data Source

PatentUS9325002B2Battery active material, nonaqueous electrolyte battery and battery pack

Publication Date: 2016.04.26 KK TOSHIBA

AI summary

A battery active material according to an embodiment includes a niobium composite oxide and a phosphorus compound being present in at least a part of the surface of the niobium composite oxide. A nonaqueous electrolyte battery according to the embodiment includes a negative electrode including the battery active material according to the embodiment, a positive electrode, and a nonaqueous electrolyte. A battery pack according to the embodiment includes at least one nonaqueous electrolyte battery according to the embodiment.