Sulfur Positive Electrode Composition for Higher Coulombic Efficiency

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Solution Overview

Problem

Current secondary batteries do not achieve sufficient battery characteristics, such as energy density and charge/discharge efficiency, particularly when using sulfur as a positive electrode active material.

Innovation Solution

Incorporating a carbon-nitrogen-containing metal compound, including carbon, nitrogen, and a metal element, into the positive electrode active material layer, which improves the diffusibility and use efficiency of lithium, thereby enhancing the battery's energy density and cyclability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If sulfur is used as positive electrode active material, then energy density is improved, but battery characteristic (coulombic efficiency and cyclability) deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidbattery characteristic

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent uses a composite material consisting of sulfur particles embedded in a porous carbon matrix, where the carbon matrix provides structural stability and conductivity while sulfur provides high energy density. This composite structure resolves the contradiction by maintaining the energy density benefits of sulfur while adding the reliability benefits of carbon.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent employs a porous carbon matrix with controlled pore structure to host sulfur particles. The porous structure allows for efficient lithium ion diffusion and accommodates volume changes during charging/discharging, thereby improving coulombic efficiency and cyclability while maintaining high energy density through optimal sulfur loading.

Inventive Principle:

Principle #31Porous materials

2Quantity of substance

If sulfur and titanium oxide are mixed and heated to obtain positive electrode active material, then battery capacity is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvebattery capacityVSAvoidmanufacturing complexity

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent performs preliminary mixing and heating of sulfur and titanium oxide to create a pre-formed composite active material before electrode fabrication. This preliminary action ensures uniform distribution and proper chemical interaction between components, simplifying subsequent manufacturing steps while achieving high battery capacity.

Inventive Principle:

Principle #10Preliminary action

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 use of a carbon-nitrogen-containing metal compound in the positive electrode active material layer improves coulombic efficiency and maintains energy density, reducing battery capacity loss even after repeated charging and discharging, resulting in a superior battery characteristic.

Implementation Method 1

improves the diffusibility of lithium

Methodology Applied

Scientific EffectIon diffusion: Diffusion

Implementation Method 2

improves coulombic efficiency

Methodology Applied

Scientific EffectElectron conduction: Conduction (electrical)

Data Source

PatentUS20250006934A1Electrode for secondary battery, and secondary battery

Publication Date: 2025.01.02 MURATA MFG CO LTD

AI summary

A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a positive electrode active material and a carbon-nitrogen-containing metal compound. The positive electrode active material includes sulfur. The carbon-nitrogen-containing metal compound includes carbon, nitrogen, and a metal element as constituent elements.