Layered Organic Electrode Material for High Energy Density Batteries

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Solution Overview

Problem

Current lithium-based secondary batteries suffer from insufficient energy density, charge-discharge capacity, and voltage polarization, leading to decreased battery performance and potential lithium metal precipitation.

Innovation Solution

A layered composition of organic backbone layers with a dicarboxylic acid anion and alkali metal element layers, where lithium coordinates with oxygen in the dicarboxylic acid, forming a crystalline structure with specific interplanar spacings, enhancing charge-discharge properties and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional organic compounds with π-electron conjugated cloud are used as electrode active materials, then high-speed charge and discharge capability is achieved, but energy density is insufficient

Engineering Contradiction:

Improvecharge and discharge speedVSAvoidenergy density

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The patent creates a composite material consisting of organic compound layers with π-electron conjugated clouds and alkali metal element layers. This composite structure combines the high-speed charge/discharge capability of the organic compound with the high energy density contribution from the alkali metal, resolving the contradiction between speed and energy density

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent merges two previously separate components (organic electrode material and alkali metal) into a single integrated layered composition. The organic compound layer and alkali metal element layer are combined in alternating fashion, allowing both materials to contribute their respective advantages simultaneously

Inventive Principle:

Principle #5Merging (Combining)

2Power

If conversion reaction negative electrodes (MOx) are used, then lithium absorption occurs at 0.5 to 1.0 V with respect to metallic lithium, but the negative electrode is considerably polarized causing battery voltage drop during discharge

Engineering Contradiction:

Improvelithium absorption capacityVSAvoidvoltage stability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

Instead of using the conventional conversion reaction approach where metal oxide converts to metal, the patent inverts the approach by using organic compounds that undergo oxidation and reduction reactions. The organic compound layer accepts lithium during charging and releases it during discharging, maintaining stable voltage characteristics while achieving high lithium absorption capacity

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If carbon materials such as graphite are used as negative electrode materials, then redox reaction occurs at about 50 mV with respect to metallic lithium, but the potential is close to lithium metal causing energy density limitations

Engineering Contradiction:

Improveredox reaction stabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating potential parameter by using organic compounds with π-electron conjugated clouds that can undergo redox reactions at higher potentials than graphite. This parameter change allows the electrode to operate at more favorable voltages, increasing the potential difference with lithium metal and thereby increasing energy density while maintaining redox reaction stability

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 novel layered composition improves charge-discharge capacity, cycling stability, and energy density by maintaining structural integrity and facilitating efficient electron and ion exchange, preventing voltage drop and lithium precipitation.

Implementation Method 1

alkali metal element layers containing an alkali metal element coordinated to oxygen contained in the carboxylic acid anion

Methodology Applied

Scientific EffectElectrostatic attraction: Coulomb's Law

Implementation Method 2

oxidation and reduction (absorption and release of lithium)

Methodology Applied

Scientific EffectOxidation and reduction: Redox Reactions

Data Source

PatentUS8932758B2Electrode active material, nonaqueous secondary battery electrode, and nonaqueous secondary battery

Publication Date: 2015.01.13 KK TOYOTA CHUO KENKYUSHO

AI summary

An electrode active material of the present invention is made of a layered composition including organic backbone layers containing an aromatic compound that is a dicarboxylic acid anion having a naphthalene backbone; and alkali metal element layers containing an alkali metal element coordinated to oxygen contained in the carboxylic acid anion to form a backbone. The layered composition has an interplanar spacing between (002) planes of 0.42400 to 0.42800 nm, an interplanar spacing between (102) planes of 0.37000 to 0.37600 nm, an interplanar spacing between (211) planes of 0.32250 to 0.32650 nm, and an interplanar spacing between (112) planes of 0.30400 to 0.30700 nm, as measured by X-ray diffraction. Preferably, the layered composition has an interplanar spacing between (200) planes of 0.50500 to 0.50950 nm as measured by X-ray diffraction.