Cathode Particle Composition for High-Capacity Lithium Secondary Batteries

Solution Overview

Problem

Lithium secondary batteries face challenges in achieving high capacity, power output, stability, and safety, particularly under harsh conditions and against penetration, due to limitations in cathode active materials.

Innovation Solution

A lithium secondary battery design incorporating a cathode active material with a first particle having a concentration gradient and a second particle with a multi-shaped structure, where the first particle includes lithium metal oxide with a specific composition and the second particle has a nickel-containing lithium metal oxide with controlled nickel, cobalt, and manganese ratios, enhancing electrical and mechanical reliability and safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a single cathode active material is used to achieve high capacity, then power output and stability deteriorate

Engineering Contradiction:

ImprovecapacityVSAvoidpower output

Core Design Contradiction:

Quantity of substanceVSPower

Solution Approach 1:

The cathode active material is segmented into two distinct particle types: first particles with concentration gradient providing high capacity, and second particles with multi-shaped structure providing high power output. This segmentation allows each particle type to specialize in different performance aspects, resolving the contradiction between capacity and power output.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite cathode active material consisting of two different particle types with distinct compositions and structures. The first particles contain lithium metal oxide with concentration gradient, while second particles contain nickel-containing lithium metal oxide with controlled ratios. This composite approach combines the advantages of both particle types to achieve both high capacity and high power output.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If a single cathode active material is used to achieve high capacity, then stability under harsh conditions deteriorates

Engineering Contradiction:

ImprovecapacityVSAvoidstability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The cathode active material is segmented into two distinct particle types: first particles with concentration gradient providing high capacity, and second particles with multi-shaped structure providing high power output. This segmentation allows each particle type to specialize in different performance aspects, resolving the contradiction between capacity and power output.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite cathode active material consisting of two different particle types with distinct compositions and structures. The first particles contain lithium metal oxide with concentration gradient, while second particles contain nickel-containing lithium metal oxide with controlled ratios. This composite approach combines the advantages of both particle types to achieve both high capacity and high power output.

Inventive Principle:

Principle #40Composite materials

3Reliability

If conventional cathode active material is used, then penetration resistance deteriorates

Engineering Contradiction:

Improveelectrical and mechanical reliabilityVSAvoidpenetration resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The second particles are designed with multi-shaped structure including rod-shaped and needle-shaped components, creating local structural variations that enhance penetration resistance. The different shapes provide varied resistance mechanisms against penetration, improving overall safety while maintaining electrical and mechanical reliability.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11909030B2Lithium secondary battery

Publication Date: 2024.02.20 SK ON CO LTD

AI summary

A lithium secondary battery includes a cathode formed from a cathode active material including a first cathode active material particle and a second cathode active material particle, an anode and a separation layer interposed between the cathode and the anode. The first cathode active material particle includes a lithium metal oxide in which at least one metal forms a concentration gradient. The second cathode active material particle includes primary particles having different shapes or crystalline structures from each other.