Nickel-Rich Cathode Material With Mn Grain-Boundary Gradient

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Nickel-based lithium transition metal oxides used in lithium secondary batteries face challenges with low capacity per unit volume, low packing density, and safety concerns at high voltages, requiring improved structural stability and cycle-life.

Innovation Solution

A cathode active material with a nickel-based composite metal oxide featuring a secondary particle structure where manganese is doped at grain boundaries, creating a concentration gradient that enhances structural stability and cycle-life, with the manganese content decreasing from the surface to the central portion of the secondary particle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If nickel-based lithium transition metal oxide is used to achieve high discharge capacity per unit weight, then high energy density is improved, but capacity per unit volume and packing density deteriorate

Engineering Contradiction:

Improvedischarge capacity per unit weightVSAvoidcapacity per unit volume

Core Design Contradiction:

Use of energy by moving objectVSVolume of moving object

Solution Approach 1:

The patent applies local quality by creating a concentration gradient of manganese dopant within the particle structure. The surface portion contains higher manganese concentration (0.1-5 mol%) compared to the central portion, with grain boundaries having the highest concentration. This spatial variation in dopant distribution allows the surface to provide structural stability while the interior maintains high capacity characteristics, thus resolving the contradiction between weight-based and volume-based capacity.

Inventive Principle:

Principle #3Local quality

2Use of energy by moving object

If nickel-based lithium transition metal oxide is driven at high voltage to improve performance, then discharge capacity is improved, but structural stability and safety deteriorate

Engineering Contradiction:

Improvedischarge capacityVSAvoidstructural stability

Core Design Contradiction:

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

Solution Approach 1:

The patent changes the chemical composition parameter by introducing manganese dopant with specific concentration gradients. The manganese content varies from 0.1-5 mol% at the surface to lower concentrations at the center, with grain boundaries having elevated manganese content. This parameter modification enhances structural stability at high operating voltages while preserving high discharge capacity, directly resolving the contradiction between performance and stability.

Inventive Principle:

Principle #35Parameter changes

3Duration of action of stationary object

If uniform manganese doping is applied throughout the particle to improve structural stability, then cycle-life is improved, but charge/discharge efficiency deteriorates due to excessive surface coating

Engineering Contradiction:

Improvecycle-lifeVSAvoidcharge/discharge efficiency

Core Design Contradiction:

Duration of action of stationary objectVSProductivity

Solution Approach 1:

The patent implements local quality through a non-uniform manganese distribution pattern. The surface portion contains manganese at 0.1-5 mol% concentration, the central portion has lower or negligible manganese content, and grain boundaries exhibit elevated manganese concentration. This localized doping strategy provides structural stability at the surface for improved cycle-life while minimizing the impact on bulk electrochemical activity, thus maintaining high charge/discharge efficiency.

Inventive Principle:

Principle #3Local quality

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 approach maximizes capacity, improves charge/discharge efficiency, and enhances thermal stability by evenly coating manganese on grain boundaries, thereby extending the cycle-life and preventing deterioration of the cathode active material.

Implementation Method 1

an amount of manganese present in the grain boundaries of the plurality of primary particles present in the surface portion is greater than an amount of manganese present inside the primary particles

Methodology Applied

Scientific EffectGrain Boundary Strengthening: Grain Boundary Strengthening

Implementation Method 2

a nickel-based composite metal oxide including a secondary particle in which a plurality of primary particles are agglomerated

Methodology Applied

Scientific EffectAgglomeration: Coagulation

Data Source

PatentUS20230317939A1Cathode active material for lithium secondary battery, preparation method therefor, and lithium secondary battery comprising same

Publication Date: 2023.10.05 SAMSUNG SDI CO LTD

AI summary

According to an embodiment, provided is a cathode active material for a lithium secondary battery, the cathode active material including a nickel-based composite metal oxide including a secondary particle in which a plurality of primary particles are agglomerated, wherein the secondary particle includes a central portion and a surface portion, the surface portion includes a nickel-based composite metal oxide doped with manganese, and an amount of manganese present in the grain boundaries of the plurality of primary particles present in the surface portion is greater than an amount of manganese present inside the primary particles.