Positive Electrode Active Material With Artificial SEI for Low Resistance

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Solution Overview

Problem

There is a need for a positive electrode active material for lithium-ion secondary batteries that enhances cycle characteristics, which refers to the ability of the battery to maintain performance over repeated charging and discharging cycles without significant degradation.

Innovation Solution

The positive electrode active material comprises lithium metal complex oxide particles combined with additive particles such as aluminum oxide, titanium oxide, magnesium oxide, silicon oxide, or zirconium oxide, with a specific surface area of 0.25 to 4.0 m²/g, which disperses on the surface of the lithium metal complex oxide particles to form an artificial Solid Electrolyte Interphase (SEI), thereby suppressing reactions that degrade the material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the specific surface area of the positive electrode active material is increased to enhance cycle characteristics, then the battery performance is improved, but the positive electrode resistance increases and material degradation accelerates

Engineering Contradiction:

Improvecycle characteristicsVSAvoidpositive electrode resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a coating layer comprising metal oxide particles (such as aluminum oxide, titanium oxide, magnesium oxide, silicon oxide, or zirconium oxide) as an intermediary substance on the surface of the lithium metal complex oxide particles. This coating layer acts as a mediator that suppresses harmful reactions between the positive electrode active material and the electrolyte, thereby reducing positive electrode resistance while maintaining cycle characteristics. The coating layer serves as a protective interface that allows ion transport while preventing direct contact and degradation reactions.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent optimizes the specific surface area parameter of the positive electrode active material to within 0.25 to 4.0 m²/g, and controls the coating layer thickness and composition parameters. By adjusting these parameters, the patent achieves a balance between enhancing cycle characteristics (which requires sufficient surface area for reactions) and minimizing positive electrode resistance (which requires limiting excessive surface area that promotes degradation).

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the specific surface area of the positive electrode active material is increased to improve cycle characteristics, then the battery durability is enhanced, but the material degradation accelerates

Engineering Contradiction:

Improvecycle characteristicsVSAvoidmaterial degradation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The coating layer of metal oxide particles serves as a protective intermediary that physically separates the lithium metal complex oxide particles from the electrolyte, preventing direct harmful reactions. This intermediary layer maintains the structural stability of the positive electrode active material during repeated charge-discharge cycles, thereby enhancing cycle characteristics while preventing material degradation. The coating layer allows lithium ion transport while blocking pathways for material decomposition.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite structure by combining lithium metal complex oxide particles with a coating layer of metal oxide particles. This composite material structure integrates the high capacity characteristics of lithium metal complex oxides with the protective and stable properties of metal oxide coatings. The composite structure maintains compositional stability during cycling while enabling enhanced cycle characteristics through the synergistic combination of materials.

Inventive Principle:

Principle #40Composite materials

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 configuration enhances the cycle characteristics of lithium-ion secondary batteries by maintaining battery performance and reducing positive electrode resistance, even after numerous charge-discharge cycles.

Implementation Method 1

one or more additive particles selected from among aluminum oxide particles, titanium oxide particles, magnesium oxide particles, silicon oxide particles, and zirconium oxide particles... disperses on the surface of the lithium metal complex oxide particles to form an artificial Solid Electrolyte Interphase (SEI), thereby suppressing reactions that degrade the material

Methodology Applied

Scientific EffectSolid Electrolyte Interphase (SEI) formation:

Data Source

PatentUS20250219092A1Positive electrode active material for lithium-ion secondary battery, and production method of positive electrode active material for lithium-ion secondary battery

Publication Date: 2025.07.03 SUMITOMO METAL MINING CO LTD

AI summary

A positive electrode active material for a lithium-ion secondary battery includes lithium metal complex oxide particles, and one or more additive particles selected from among aluminum oxide particles, titanium oxide particles, magnesium oxide particles, silicon oxide particles, and zirconium oxide particles. A specific surface area of the positive electrode active material is 0.25 m2/g or more and 4.0 m2/g or less.