High-Ni Cathode Material Structure for Better Cycle Life

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The use of lithium transition metal oxides with a high proportion of Ni (91 mol % or more) as positive electrode active materials in non-aqueous electrolyte secondary batteries leads to significant deterioration in charge/discharge cycle characteristics.

Innovation Solution

A Ni-containing lithium transition metal oxide with a layered structure is used, where the proportion of Ni is between 91 mol % and 99 mol % relative to the total number of moles of metal elements except for Li, and 1 mol % to 2.5 mol % of transition metals are present in the Li layer, along with a half width of the diffraction peak of the (208) plane in the range of 0.30° to 0.50° in an X-ray diffraction pattern.

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 is improved, 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 of the layered structure, rather than uniformly distributing them throughout the material. This localized placement allows the Li layer to maintain its structural integrity and stability during charge/discharge cycles, while the high-Ni transition metal oxide layers continue to provide high capacity. The transition metals in the Li layer act as structural stabilizers without significantly reducing the overall Ni content and capacity of the active material.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite layered structure where different components serve different functions: the high-Ni transition metal oxide layers (91-99 mol % Ni) provide high battery capacity, while the Li layer containing transition metals (1-2.5 mol %) provides structural stability. This composite approach allows the material to simultaneously achieve high capacity and good cycle characteristics by combining the advantages of different compositional regions within a single layered structure.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If the proportion of Ni is increased to 91 mol % or more, then energy density is improved, but structural stability is reduced

Engineering Contradiction:

Improveenergy densityVSAvoidlayered structure stability

Core Design Contradiction:

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

Solution Approach 1:

The patent uses local quality by concentrating transition metals specifically in the Li layer rather than distributing them throughout the entire structure. This localized approach allows the high-Ni regions to maintain high energy density while the transition metal-containing Li layer provides localized structural support and stability, preventing degradation during cycling.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The Li layer containing transition metals acts as an intermediary between the high-Ni active material layers. This intermediary layer provides structural buffering and stability, mediating the mechanical and chemical stresses that would otherwise cause degradation of the high-Ni structure during charge/discharge cycles, thereby preserving both energy density and structural integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 stabilizes the layered structure and suppresses deterioration in charge/discharge cycle characteristics, ensuring better performance and longevity of the non-aqueous electrolyte secondary battery.

Implementation Method 1

a Ni-containing lithium transition metal oxide having a layered structure

Methodology Applied

Scientific EffectLayered structure:

Implementation Method 2

This configuration stabilizes the layered structure

Methodology Applied

Scientific EffectCrystal structure stabilization:

Implementation Method 3

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

Implementation Method 4

in an X-ray diffraction pattern with X-ray diffraction

Methodology Applied

Scientific EffectDiffraction: Diffraction

Data Source

PatentUS20250038198A1Positive electrode active material for non-aqueous electrolyte secondary cell, and non-aqueous electrolyte secondary cell

Publication Date: 2025.01.30 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°.