Na-S Coated High-Nickel Cathode Material for Low-Impurity Cycling

Solution Overview

Problem

Rechargeable lithium batteries with high nickel content in their positive electrode active materials face challenges related to reduced lifespan and stability due to the high energy density requirements.

Innovation Solution

A positive electrode active material is developed with a reduced amount of impurities, specifically lithium composite oxide particles with a controlled composition and structure, including sodium and sulfur, which are optimized through a nickel-based hydroxide precursor and a wet coating process to enhance charging/discharging capacity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If high nickel content is used in the positive electrode active material to achieve high energy density, then the energy density is improved, but the lifespan and stability of the rechargeable lithium battery are reduced

Engineering Contradiction:

Improveenergy densityVSAvoidlifespan and stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the inner core contains high nickel content (Ni0.8Co0.1Mn0.1O2) for high energy density, while the outer shell contains lower nickel content (Ni0.8Co0.05Mn0.15O2) for improved stability. This spatial differentiation of composition allows each region to perform its specialized function: the core provides capacity while the shell provides structural stability and reduces impurity formation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining two different lithium nickel manganese cobalt oxide compositions with varying nickel contents to form a core-shell structured positive electrode active material. This composite approach allows the battery to benefit from both high nickel content (for energy density) and lower nickel content (for stability), effectively resolving the contradiction between energy density and reliability.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If high nickel content is used in the positive electrode active material, then the energy density is improved, but the amount of impurities increases

Engineering Contradiction:

Improveenergy densityVSAvoidamount of impurities

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the inner core contains high nickel content (Ni0.8Co0.1Mn0.1O2) for high energy density, while the outer shell contains lower nickel content (Ni0.8Co0.05Mn0.15O2) for improved stability. This spatial differentiation of composition allows each region to perform its specialized function: the core provides capacity while the shell provides structural stability and reduces impurity formation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies preliminary action by pre-forming the core-shell structure before final sintering, where the outer shell is already in place to protect the inner core during the high-temperature processing. This preliminary protective layer prevents impurity formation and migration during manufacturing, ensuring high purity of the final product while maintaining high energy density.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional fabrication methods are used for high nickel positive electrode active material, then the production process is simple, but the charging/discharging capacity and efficiency are reduced

Engineering Contradiction:

Improveproduction process simplicityVSAvoidcharging/discharging capacity and efficiency

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the positive electrode active material into two distinct compositional regions (core and shell) with different nickel contents. The fabrication process is segmented into sequential steps: first forming the core material, then coating the shell material, and finally sintering. This segmented approach enables precise control over the composition gradient, optimizing both charging/discharging capacity and efficiency while maintaining manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by pre-forming the core-shell structure before final sintering, where the outer shell is already in place to protect the inner core during the high-temperature processing. This preliminary protective layer prevents impurity formation and migration during manufacturing, ensuring high purity of the final product while maintaining high energy density.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250192171A1Positive electrode active material and rechargeable lithium battery including the same

Publication Date: 2025.06.12 SAMSUNG SDI CO LTD

AI summary

Positive electrode active materials, methods of fabricating the positive electrode active materials, positive electrodes including the positive electrode active materials, and rechargeable lithium batteries including the positive electrodes are disclosed. The positive electrode active material includes a positive electrode active material including a plurality of particles including lithium composite oxide represented by Chemical Formula 1.LiaNixMi1-xOb Chemical Formula 1In Chemical Formula 1, a is about 0.5 to about 1.5. x is about 0.6 to about 0.99. b is about 1.8 to about 2.2. 1-x may be about 0.01 to about 0.4. M includes at least one element selected from among Co, Al, Mn, Na, Mg, Ca, Y, Ti, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Cu, Ag, Zn, B, Ga, C, Si, and Sn. The particle includes Na and S. A mass fraction (Na/S) of the Na to the S is about 0.03 to about 0.2.