Garnet Oxide Coated Cathode for Lithium Battery Stability

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Solution Overview

Problem

High-voltage cathode active materials in lithium batteries cause side reactions with the electrolyte, leading to degradation of high-rate characteristics and lifespan, due to the production of by-products such as free transition metals or gases.

Innovation Solution

A composite cathode active material is developed, comprising a lithium intercalatable material coated with a garnet oxide shell, where the garnet oxide content is limited to about 1.9 weight percent or less, to improve lithium ion transfer and reduce side reactions with the electrolyte.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high-voltage cathode active materials are used to improve battery voltage and energy density, then battery voltage and energy density are improved, but side reactions with electrolyte occur leading to degradation of high-rate characteristics and lifespan

Engineering Contradiction:

Improvebattery voltage and energy densityVSAvoidhigh-rate characteristics and lifespan

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A garnet oxide coating layer is applied as an intermediary between the high-voltage cathode active material and the electrolyte. This coating layer acts as a protective barrier that prevents direct contact and side reactions between the cathode material and electrolyte, thereby maintaining high-rate characteristics and extending battery lifespan while preserving the high-voltage performance of the underlying cathode material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure consisting of high-voltage cathode active material particles coated with garnet oxide. This composite material combines the high voltage and energy density advantages of the cathode material with the protective and ion-conductive properties of the garnet oxide coating, achieving both high performance and long stability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a garnet oxide coating is applied to prevent side reactions with electrolyte, then high-rate characteristics and lifespan are improved, but lithium ion transfer may be hindered if coating amount is excessive

Engineering Contradiction:

Improvehigh-rate characteristics and lifespanVSAvoidlithium ion transfer rate

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The invention optimizes the coating parameters by controlling the garnet oxide content to be within a specific range (0.1-5 wt%, preferably 0.5-2 wt%). This parameter optimization ensures that the coating is sufficiently thick to provide protection against side reactions while remaining thin enough to allow efficient lithium ion transfer, thus balancing protection and ion conductivity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The garnet oxide coating provides localized protection at the interface between the cathode material and electrolyte, rather than requiring bulk modification of the entire cathode structure. This localized approach maintains the high-voltage properties of the bulk cathode material while providing surface-level protection and ion transport pathways.

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 composite cathode active material enhances high-rate characteristics and lifespan of lithium batteries by suppressing side reactions and preventing electrolyte decomposition, resulting in improved battery performance.

Implementation Method 1

a composite cathode active material includes: a lithium intercalatable material; and a garnet oxide, wherein an amount of the garnet oxide is about 1.9 weight percent (wt %) or less, based on a total weight of the composite cathode active material

Methodology Applied

Scientific EffectChemical barrier effect:

Implementation Method 2

to improve lithium ion transfer and reduce side reactions with the electrolyte

Methodology Applied

Scientific EffectIon conduction:

Data Source

PatentUS11101461B2Composite cathode active material, method of preparing the composite cathode active material, and cathode and lithium battery each including the composite cathode active material

Publication Date: 2021.08.24 SAMSUNG ELECTRONICS CO LTD

AI summary

A composite cathode active material, a method of preparing the composite cathode active material, a cathode including the composite cathode active material, and a lithium battery including the cathode. The composite cathode active material includes a lithium intercalatable material; and a garnet oxide, wherein an amount of the garnet oxide is about 1.9 wt % or less, based on a total weight of the composite cathode active material.