High-Ni Positive Electrode Material With Li-Layer Stabilization

Solution Overview

Problem

Lithium transition metal oxides with a high proportion of Ni relative to other metal elements in non-aqueous electrolyte secondary batteries suffer from deteriorated charge/discharge cycle characteristics.

Innovation Solution

A Ni-containing lithium transition metal oxide with a layered structure, where Ni constitutes 91-99 mol% of the metal elements excluding Li, and 1-2.5 mol% of transition metals are present in the Li layer, along with a specific half-width range of the (208) plane diffraction peak in X-ray diffraction, stabilizing the Li layer and improving charge/discharge cycle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a lithium transition metal oxide with high Ni proportion (91 mol% or more) is used as positive electrode active material, then battery capacity increases, but charge/discharge cycle characteristics are remarkably deteriorated

Engineering Contradiction:

Improvebattery capacityVSAvoidcharge/discharge cycle characteristics

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by introducing transition metals specifically into the Li layer at controlled concentrations (1-2.5 mol% relative to total transition metals). This localized modification of the Li layer region stabilizes the layered structure without significantly reducing the overall high Ni content (91-99 mol%) in the bulk material, thereby maintaining high capacity while improving cycle characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by controlling the half width n of the (208) plane diffraction peak within a specific range (0.30°≤n≤0.50°). This parameter control reflects and ensures the proper structural state of the layered oxide, optimizing both capacity and cycle stability through precise structural parameter management.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If Ni proportion is increased to 91 mol% or more, then energy density improves, but structural stability of layered structure deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidstructural stability of layered structure

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by introducing transition metals specifically into the Li layer at controlled concentrations (1-2.5 mol% relative to total transition metals). This localized modification of the Li layer region stabilizes the layered structure without significantly reducing the overall high Ni content (91-99 mol%) in the bulk material, thereby maintaining high capacity while improving cycle characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure by combining high-Ni lithium transition metal oxide with additional transition metals in the Li layer. This composite approach at the atomic level (multiple transition metal elements in the Li layer) provides structural stabilization while preserving the high energy density characteristics of the Ni-rich bulk composition.

Inventive Principle:

Principle #40Composite materials

3Reliability

If transition metals are added to Li layer, then charge/discharge cycle characteristics improve, but manufacturing complexity increases

Engineering Contradiction:

Improvecharge/discharge cycle characteristicsVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes parameter changes by controlling the half width n of the (208) plane diffraction peak within a specific range (0.30°≤n≤0.50°). This parameter control reflects and ensures the proper structural state of the layered oxide, optimizing both capacity and cycle stability through precise structural parameter management.

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

This configuration enhances the stability of the layered structure, allowing smooth Li ion movement and reducing deterioration in charge/discharge cycle characteristics, thereby maintaining battery performance.

Implementation Method 1

charge/discharge is performed by movement of lithium ions and the like between the positive electrode and the negative electrode

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

a half width n of a diffraction peak of the (208) plane of the Ni-containing lithium transition metal oxide, in an X-ray diffraction pattern with X-ray diffraction

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS12142763B2Positive electrode active material for non-aqueous electrolyte secondary cell, and non-aqueous electrolyte secondary cell

Publication Date: 2024.11.12 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

The positive electrode active material for a non-aqueous electrolyte secondary cell according to an embodiment of the present disclosure is characterized in having a Ni-containing lithium transition metal oxide having a layered structure; the proportion of Ni in the lithium transition metal oxide being 91 to 96 mol % relative to the total number of moles of metal elements excluding Li; a transition metal being present in the Li layer of the layered structure at an amount of 1 to 2.5 mol % relative to the total number of moles of transition metals in the Ni-containing lithium transition metal oxide; and the Ni-containing lithium transition metal oxide being such that the half width n of the diffraction peak for the (208) plane in an X-ray diffraction pattern obtained by X-ray diffraction is 0.30°≤n≤0.50°.