Fluorine-Boron Coated Li-Rich Cathode for Stable Rate Performance

Solution Overview

Problem

Existing overlithiated lithium manganese-based oxides suffer from low electrochemical properties and stability due to the elution of transition metals, which leads to decreased rate performance and capacity retention in lithium secondary batteries.

Innovation Solution

A positive electrode active material is developed by forming a coating layer containing fluorine and boron on the surface of the lithium manganese-based oxide, which suppresses the elution of transition metals and enhances the electrochemical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If an overlithiated lithium manganese-based oxide is used as a positive electrode active material, then high discharge capacity can be achieved, but rate performance deteriorates due to low electrical conductivity caused by excessive Mn content

Engineering Contradiction:

Improvedischarge capacityVSAvoidrate performance

Core Design Contradiction:

Quantity of substanceVSSpeed

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the inner core contains high-Mn overlithiated lithium manganese-based oxide for high capacity, while the outer shell contains low-Mn overlithiated lithium manganese-based oxide for improved electrical conductivity and rate performance. This spatial differentiation allows each region to optimize its properties for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining two different overlithiated lithium manganese-based oxide phases with distinct Mn contents to form a composite positive electrode active material. The composite structure integrates the high-capacity advantage of high-Mn oxide with the high-conductivity advantage of low-Mn oxide, achieving both high discharge capacity and good rate performance simultaneously.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If an overlithiated lithium manganese-based oxide with excessive Mn is used, then high capacity is achieved, but stability deteriorates due to elution of transition metals

Engineering Contradiction:

ImprovecapacityVSAvoidstability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the inner core contains high-Mn overlithiated lithium manganese-based oxide for high capacity, while the outer shell contains low-Mn overlithiated lithium manganese-based oxide for improved electrical conductivity and rate performance. This spatial differentiation allows each region to optimize its properties for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining two different overlithiated lithium manganese-based oxide phases with distinct Mn contents to form a composite positive electrode active material. The composite structure integrates the high-capacity advantage of high-Mn oxide with the high-conductivity advantage of low-Mn oxide, achieving both high discharge capacity and good rate performance simultaneously.

Inventive Principle:

Principle #40Composite materials

3Quantity of substance

If LiNiO2-based positive electrode active material is synthesized, then high discharge capacity is achieved, but manufacturing difficulty increases due to cation mixing between Li and transition metals

Engineering Contradiction:

Improvedischarge capacityVSAvoidsynthesis difficulty

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the Mn content parameter within a specific range (0.5 < Mn < 0.95) and the lithium molar content parameter (higher than the sum of transition metal molar contents) to achieve the desired crystal structure and properties while avoiding cation mixing issues. This parameter optimization enables successful synthesis of the overlithiated lithium manganese-based oxide.

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 solution improves the discharge capacity, charge/discharge efficiency, and rate performance of lithium secondary batteries, while maintaining high stability by reducing side reactions between the positive electrode active material and the electrolyte.

Implementation Method 1

forming a coating layer containing fluorine and boron on the surface of the lithium manganese-based oxide, which suppresses the elution of transition metals

Methodology Applied

Scientific EffectSurface passivation: Adsorption

Implementation Method 2

when lithium ions are intercalated/deintercalated into/from a positive electrode and a negative electrode

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 3

Batteries store electrical power by using materials facilitating an electrochemical reaction at a positive electrode and a negative electrode

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS20250118744A1Positive electrode active material and lithium secondary battery comprising the same

Publication Date: 2025.04.10 ECOPRO BM CO LTD

AI summary

The present invention relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a positive electrode active material including an overlithiated lithium manganese-based oxide, which can improve the electrochemical properties of a lithium secondary battery including discharge capacity and rate performance, which are reduced by lithium and manganese present in excess in the lithium manganese-based oxide, and a lithium secondary battery including the same.