Cobalt-Free Cathode Material With Core-Shell Ni/Mn Gradient

Solution Overview

Problem

Cobalt-free lithium composite oxides face limitations in electrochemical properties and stability, leading to increased resistance and reduced battery lifetime due to reduced cobalt content, particularly in nickel-cobalt-manganese (NCM) or nickel-cobalt-aluminum (NCA) compositions.

Innovation Solution

A cobalt-free lithium composite oxide with controlled bulk structure and composition, featuring an inner bulk and outer bulk with distinct Ni/Mn molar ratios and volume fractions, and a cation mixing layer on the surface, along with a coating layer to enhance electroconductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If cobalt content is reduced in lithium composite oxide to lower cost, then cost is reduced, but resistance increases and electrochemical properties deteriorate

Engineering Contradiction:

Improvecobalt contentVSAvoidelectrochemical properties

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the inner bulk contains high nickel content (Ni/Mn ratio > 4.26) for high capacity, while the outer bulk contains lower nickel content (Ni/Mn ratio 1.0-2.33) for stability. This spatial differentiation of composition allows the material to simultaneously achieve high electrochemical performance and structural stability without cobalt

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining nickel-rich and manganese-rich regions within the same particle structure. The inner bulk and outer bulk form a composite structure that integrates the high capacity characteristics of nickel-based materials with the stability characteristics of manganese-based materials, eliminating the need for cobalt while maintaining both performance and stability

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If cobalt content is reduced in lithium composite oxide to lower cost, then cost is reduced, but particle stability deteriorates and battery lifetime is reduced

Engineering Contradiction:

Improvecobalt contentVSAvoidparticle stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the inner bulk contains high nickel content (Ni/Mn ratio > 4.26) for high capacity, while the outer bulk contains lower nickel content (Ni/Mn ratio 1.0-2.33) for stability. This spatial differentiation of composition allows the material to simultaneously achieve high electrochemical performance and structural stability without cobalt

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies beforehand cushioning by introducing a coating layer on the particle surface that prevents direct contact between the lithium composite oxide and the electrolyte. This coating layer acts as a protective barrier that cushions the particle structure from degradation during cycling, maintaining particle stability and preventing early battery failure

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Use of energy by moving object

If nickel-based lithium composite oxide is used for high energy capacity, then energy capacity increases, but thermal stability and electrochemical properties are insufficient

Engineering Contradiction:

Improveenergy capacityVSAvoidthermal 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 bulk contains high nickel content (Ni/Mn ratio > 4.26) for high capacity, while the outer bulk contains lower nickel content (Ni/Mn ratio 1.0-2.33) for stability. This spatial differentiation of composition allows the material to simultaneously achieve high electrochemical performance and structural stability without cobalt

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies beforehand cushioning by introducing a coating layer on the particle surface that prevents direct contact between the lithium composite oxide and the electrolyte. This coating layer acts as a protective barrier that cushions the particle structure from degradation during cycling, maintaining particle stability and preventing early battery failure

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

The cobalt-free lithium composite oxide exhibits improved thermal stability and electrochemical properties suitable for commercialization, enhancing capacity and rate capability while maintaining surface stability and electroconductivity.

Implementation Method 1

a lithium secondary battery storing electrical energy due to a difference in chemical potential when lithium ions are intercalated/deintercalated into/from a positive electrode and a negative electrode

Methodology Applied

Scientific EffectIntercalation/Deintercalation:

Implementation Method 2

Batteries store electrical power by using materials having an electrochemical reaction at a positive electrode and a negative electrode

Methodology Applied

Scientific EffectElectrochemical reaction:

Implementation Method 3

along with a coating layer to enhance electroconductivity

Methodology Applied

Scientific EffectElectroconductivity enhancement:

Data Source

PatentUS20260094819A1Positive electrode active material and lithium secondary battery using the same

Publication Date: 2026.04.02 ECOPRO BM CO LTD

AI summary

The present invention relates to a cobalt-free positive electrode active material having improved thermal stability and electrochemical properties, and a lithium secondary battery using the same.