Positive Electrode Material Using Composite Solid Electrolytes

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Solution Overview

Problem

Current battery technologies face limitations in improving charge-discharge characteristics, particularly in terms of lithium ion conductivity and thermodynamic stability of solid electrolytes, which affect the overall performance and cycle life of batteries.

Innovation Solution

A positive electrode material comprising a combination of a positive electrode active material, a first solid electrolyte (Li, M1, and X1), and a second solid electrolyte (Li, M2, O, and X2), where M1 is selected from Al, Ti, or Zr, M2 is from Group 5 elements, and X1 and X2 include fluorine, enhancing lithium ion conductivity and thermodynamic stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single solid electrolyte material is used in the positive electrode, then the structure is simple, but the lithium ion conductivity and thermodynamic stability are insufficient

Engineering Contradiction:

Improvelithium ion conductivityVSAvoidelectrolyte structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a composite solid electrolyte structure consisting of a fluoride-based solid electrolyte (Li3-x-aM1xM2aF6-bOz) and an oxyhalide-based solid electrolyte (Li2-yM3O4-zX2z). This composite material approach combines the high ionic conductivity of fluoride electrolytes with the thermodynamic stability of oxyhalide electrolytes, achieving both improved lithium ion conductivity and enhanced stability without requiring complex multi-layer configurations.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent optimizes the chemical composition parameters of the solid electrolyte, specifically controlling the ratios of M1, M2, and M3 elements and the fluorine content (F). By adjusting these compositional parameters, the patent achieves optimal balance between ionic conductivity and thermodynamic stability, resolving the contradiction through parameter optimization rather than structural complexity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If fluorine content is increased to improve lithium ion conductivity, then conductivity improves, but thermodynamic stability may deteriorate

Engineering Contradiction:

Improvelithium ion conductivityVSAvoidthermodynamic stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent precisely controls the fluorine content parameter (F) within optimal ranges to maximize lithium ion conductivity while preventing excessive fluorine from compromising thermodynamic stability. This parameter optimization allows the fluoride-based solid electrolyte to contribute high conductivity without sacrificing the stability provided by the oxyhalide component.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The composite structure allows the fluoride-based electrolyte to provide high ionic conductivity through optimized fluorine content, while the oxyhalide-based electrolyte simultaneously provides thermodynamic stability. This division of functional roles within the composite material resolves the contradiction between conductivity and stability.

Inventive Principle:

Principle #40Composite materials

3Productivity

If M1, M2, and M3 element ratios are not optimized, then manufacturing is easier, but lithium ion conductivity and charge-discharge characteristics deteriorate

Engineering Contradiction:

Improvecharge-discharge characteristicsVSAvoidelement ratio control

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent establishes specific optimal ranges for the ratios of M1, M2, and M3 elements in the solid electrolyte composition. By defining these parameter ranges, the patent enables manufacturers to achieve high charge-discharge characteristics through controlled composition rather than complex processing, balancing manufacturability with performance.

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 proposed configuration significantly improves lithium ion conductivity and thermodynamic stability, reducing internal resistance and enhancing the charge-discharge characteristics and cycle life of batteries, while inhibiting the formation of high-resistance phases.

Implementation Method 1

improving the charge-discharge characteristics of a battery... significantly improves lithium ion conductivity

Methodology Applied

Scientific EffectIonic conductivity: Conduction (electrical)

Data Source

PatentUS20250015291A1Positive electrode material and battery containing the same

Publication Date: 2025.01.09 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A positive electrode material of the present disclosure comprises a positive electrode active material, a first solid electrolyte, and a second solid electrolyte. The first solid electrolyte consists of Li, M1, and X1. The second solid electrolyte consists of Li, M2, O, and X2. M1 is at least one selected from the group consisting of Al, Ti, and Zr. M2 is at least one selected from Group 5 elements. X1 and X2 are each independently at least one selected from the group consisting of F, Cl, Br, and I and comprise F.