Lithium-Sulfur Battery Cathode Material Production via Solution Mixing

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Solution Overview

Problem

The existing methods for producing lithium sulfur battery cathode materials face challenges in achieving uniform mixing of fine lithium sulfate and carbon particles at high temperatures, leading to difficulties in manufacturing high-performance lithium sulfur batteries.

Innovation Solution

A production method involving the preparation of a dispersed solution with carbon particles in a lithium sulfate solution, followed by adding a solvent where lithium sulfate is insoluble, separating precursor particles, and converting them into active material particles by heating under an inert atmosphere, which facilitates the formation of a lithium sulfide/carbon composite with improved conductivity and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If lithium sulfate and carbon fine particles are uniformly mixed at high temperature, then the cathode material performance is improved, but the manufacturing difficulty increases

Engineering Contradiction:
Improveuniformity of mixingVSAvoidmanufacturing difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the physical state of reactants from solid particles to dissolved/colloidal state in solution. By dissolving lithium sulfate in water and dispersing carbon particles to form a homogeneous liquid mixture, the uniformity of mixing is dramatically improved while eliminating the difficulty of mixing fine solid particles at high temperature.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Water serves as an intermediary medium to facilitate uniform mixing. The lithium sulfate dissolves in water to form a homogeneous solution, and carbon particles are dispersed throughout this solution, creating a uniform precursor that can be easily processed without direct high-temperature mixing of solids.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If high temperature heating is applied to mix lithium sulfate and carbon particles, then the reaction efficiency is improved, but the process complexity increases

Engineering Contradiction:
Improvereaction efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention performs preliminary mixing and homogenization in the liquid phase before heating. The uniform distribution of lithium sulfate and carbon in the aqueous precursor solution ensures that subsequent heating proceeds efficiently without requiring complex mixing mechanisms during the high-temperature reaction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces mechanical mixing of solid particles with chemical dissolution and colloidal dispersion in liquid. This substitution eliminates the need for complex mechanical mixing systems during heating, as the uniform liquid precursor naturally maintains homogeneity during the thermal reaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This method enables the easy production of high-performance lithium sulfur battery cathode materials with enhanced charge-discharge characteristics and high theoretical capacity, overcoming the challenges of temperature and mixing issues in existing processes.

Implementation Method 1

a step of changing the precursor particle into an active material particle by heating the precursor particle under an inert atmosphere

Methodology Applied
Scientific EffectReduction: Reduction

Data Source

PatentEP3214674B1Method for producing cathode material for lithium-sulfur battery
Publication Date: 2019.05.15 NAT UNIV CORP YOKOHAMA NAT UNIV
  • EP3214674B1 patent drawingFigure 1
  • EP3214674B1 patent drawingFigure 2
  • EP3214674B1 patent drawingFigure 3A~3C

AI summary

A production method for a cathode material 44 of a lithium sulfur battery 10 includes, in sequence: a step of preparing a first dispersed solution 30 in which a carbon particle 40 is dispersed in a lithium sulfate solution; a step of adding a solvent in the first dispersed solution 30, the solvent being a solvent in which lithium sulfate is insoluble; a step of separating a precursor particle 41 from the first dispersed solution 31 in which the solvent is added; and a step of changing the precursor particle 41 into a cathode active material particle 44 by heating the precursor particle 41 under an inert atmosphere.