Niobium-Titanium Composite Oxide Anode for Rapid Pulse Battery

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Solution Overview

Problem

Secondary batteries, particularly those used in vehicles, face challenges with rapid charge and discharge performance due to dendrite formation on carbon-based negative electrodes, leading to potential internal short circuits and safety concerns, while metal composite oxides like titanium oxide offer stability but compromise on energy density and capacity.

Innovation Solution

A niobium-titanium composite oxide (Nb2TiO7) is used as an active material in the battery, combining with orthorhombic niobium oxide to enhance lithium ion conduction and maintain electric neutrality, thereby achieving high energy density and rapid pulse input-output performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a carbon-based negative electrode is used to achieve high energy density, then the theoretical capacity is high, but dendrites of metallic lithium precipitate during rapid charge/discharge causing internal short circuits and safety issues

Engineering Contradiction:

Improvetheoretical capacityVSAvoidsafety and stability during rapid charge/discharge

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention changes the material parameter from carbon-based materials to metal composite oxides (titanium oxide, niobium oxide), which fundamentally alters the electrochemical properties including potential, capacity, and dendrite formation behavior, thereby resolving the contradiction between high capacity and safety

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite oxide materials combining titanium and niobium elements, leveraging the synergistic effects of both metals to achieve both high theoretical capacity (387 mAh/g for Nb2TiO7) and excellent safety performance by preventing lithium dendrite precipitation

Inventive Principle:

Principle #40Composite materials

2Reliability

If titanium oxide is used as the negative electrode active material to prevent dendrite formation and improve stability, then rapid charge/discharge stability and life are improved, but the energy density decreases due to higher potential and lower theoretical capacity per unit mass

Engineering Contradiction:

Improvestability during rapid charge/dischargeVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention merges titanium oxide and niobium oxide into a composite material (Nb2TiO7), combining the high stability and dendrite resistance of titanium oxide with the high theoretical capacity of niobium oxide, thereby achieving both reliability and high energy density simultaneously

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

By changing from pure titanium oxide to niobium-titanium composite oxide, the invention optimizes key parameters including theoretical capacity (increasing to 387 mAh/g), potential, and lithium ion conduction properties, resolving the contradiction between stability and energy density

Inventive Principle:

Principle #35Parameter changes

3Productivity

If rapid charge/discharge is performed repeatedly in a battery with carbon-based negative electrode, then the charging time is short and power delivery is fast, but heat generation and ignition may occur due to dendrite formation

Engineering Contradiction:

Improvecharging speedVSAvoidheat generation and ignition risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention converts the potential harm of rapid charge/discharge (which causes dendrites in carbon-based electrodes) into a beneficial operation mode. By using metal composite oxides, the same rapid charge/discharge conditions that would be dangerous become safe and effective, achieving both high productivity and safety

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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-titanium composite oxide with orthorhombic niobium oxide structure enables a battery with improved energy density and rapid charge/discharge capabilities, reducing dendrite formation risks and extending battery life.

Implementation Method 1

tetravalent titanium ions are reduced to trivalent titanium ions when lithium ions are inserted, pentavalent niobium ions are reduced to trivalent niobium ions

Methodology Applied

Scientific EffectReduction: Reduction

Implementation Method 2

tetravalent titanium ions are reduced to trivalent titanium ions when lithium ions are inserted, pentavalent niobium ions are reduced to trivalent niobium ions, also

Methodology Applied

Scientific EffectRedox Reactions: Redox Reactions

Implementation Method 3

enhance lithium ion conduction and maintain electric neutrality

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentUS10749169B2Active material, electrode, secondary battery, battery pack, and vehicle

Publication Date: 2020.08.18 KK TOSHIBA

AI summary

According to one embodiment, an active material is provided. The active material includes a first phase including a niobium-titanium composite oxide, and a second phase adjacent to the first phase and including an orthorhombic niobium oxide. The active material is a particle in which a second (010) plane of the orthorhombic niobium oxide is in contact with a first (010) plane of the niobium-titanium composite oxide in at least a part of a contact interface between the first phase and the second phase.