Li3YX6 Solid Electrolyte Composition Without Phase Transition

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Solution Overview

Problem

Existing solid electrolyte materials for batteries face challenges in achieving high lithium ion conductivity and stability across a wide temperature range without phase transitions, and often generate hydrogen sulfide when exposed to air.

Innovation Solution

A solid electrolyte material with the composition Li3YX6, where X is Cl, Br, or I, is developed, with a modulated crystal structure that allows for high lithium ion conductivity and stability from -30°C to 80°C, avoiding phase transitions and the generation of hydrogen sulfide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfide solid electrolyte is used, then lithium ion conductivity is improved, but hydrogen sulfide is generated when exposed to air

Engineering Contradiction:

Improvelithium ion conductivityVSAvoidhydrogen sulfide generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by replacing sulfur-based electrolytes with halide-based electrolytes containing Li, Y, and halogen elements (Cl, Br, I) in specific ratios, thereby eliminating hydrogen sulfide generation while maintaining high lithium ion conductivity through optimized compositional parameters

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite halide solid electrolyte materials combining lithium, yttrium, and halogen elements in specific compositions (such as Li3YBr6, Li3YCl6, or their mixtures), creating a composite material system that achieves both high conductivity and chemical stability without generating harmful gases

Inventive Principle:

Principle #40Composite materials

2Reliability

If solid electrolyte material is designed for high conductivity, then ion conductivity is improved, but phase transitions occur outside temperature range

Engineering Contradiction:

Improveion conductivityVSAvoidphase transition stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent optimizes compositional parameters (ratios of Li, Y, and halogen elements) to tune the phase transition temperature of the solid electrolyte material, shifting it outside the battery operating range while maintaining high ion conductivity through careful parameter selection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces local compositional variations and doping strategies to modify specific regions of the crystal structure, thereby controlling phase transition behavior locally while preserving the overall high conductivity pathway for lithium ions

Inventive Principle:

Principle #3Local quality

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 material achieves ion conductivities of more than 1 × 10^-4 S/cm, enabling rapid charging and discharging of all-solid secondary batteries with improved safety by maintaining high conductivity and stability without phase transitions within the battery's operational temperature range.

Implementation Method 1

a solid electrolyte material having high lithium ion conductivity can be realized

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP3736830B1Solid electrolyte material and battery

Publication Date: 2024.01.03 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

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AI summary

Provided is a solid electrolyte material represented by the following composition formula (1): Li3YX6 Formula (1) where X is two or more kinds of elements selected from the group consisting of Cl, Br, and I.