Cobalt-Boron Coated Nickel Cathode for Crack-Stable Li Batteries

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Nickel-based active materials in lithium secondary batteries suffer from deterioration and side reactions during charging and discharging, leading to reduced lifetime and efficiency due to micro-crack formation and irreversible reactions with the electrolyte.

Innovation Solution

A composite positive electrode active material is developed, featuring a nickel-based active material with a cobalt-boron compound-containing coating layer, which suppresses micro-crack formation and enhances phase stability by reducing direct contact with the electrolyte, thereby improving ion transfer and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a nickel-based active material is used to achieve high energy density, then the battery capacity increases, but micro-cracks form and side reactions with electrolyte occur during charging and discharging, leading to deterioration

Engineering Contradiction:

Improvebattery capacityVSAvoidphase stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies composite materials by forming a coating layer containing cobalt oxide and amorphous boron on the surface of the nickel-based active material. This composite structure combines the high capacity benefits of nickel-based materials with the protective and stabilizing properties of the coating layer, resolving the contradiction between high energy density and phase stability during charging-discharging cycles

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent utilizes parameter changes by controlling the oxidation state of cobalt (Co3+ and Co4+) and incorporating amorphous boron in the coating layer. These compositional and structural parameter changes enable the coating to provide both protective functions and electrochemical activity, maintaining phase stability while supporting high capacity operation

Inventive Principle:

Principle #35Parameter changes

2Speed

If the nickel-based active material is directly exposed to electrolyte, then ion transfer is straightforward, but irreversible reactions occur leading to reduced lifetime

Engineering Contradiction:

Improveion transfer rateVSAvoidbattery lifetime

Core Design Contradiction:

SpeedVSDuration of action of moving object

Solution Approach 1:

The coating layer containing cobalt oxide and amorphous boron serves as an intermediary between the nickel-based active material and the electrolyte. This intermediate layer facilitates ion transfer while preventing direct contact between the electrolyte and the nickel-based material, thereby eliminating irreversible reactions and extending battery lifetime without sacrificing ion transfer speed

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a coating layer is formed to protect the active material, then phase stability improves, but the complexity of preparation process increases

Engineering Contradiction:

Improvephase stabilityVSAvoidpreparation process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by incorporating the protective coating components (cobalt precursor and boron compound) into the slurry before electrode formation. This allows the coating layer to be formed simultaneously with the electrode structure during a single preparation process, avoiding the need for separate coating steps and reducing overall process complexity while maintaining phase stability

Inventive Principle:

Principle #10Preliminary action

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 composite material significantly improves the lifetime and high-rate characteristics of lithium secondary batteries by stabilizing the nickel-based active material and reducing irreversible reactions, maintaining performance at both room and high temperatures.

Implementation Method 1

a cobalt-boron compound-containing coating layer formed on a surface of the nickel-based active material... suppresses micro-crack formation and enhances phase stability by reducing direct contact with the electrolyte

Methodology Applied

Scientific EffectPhysical barrier protection:

Implementation Method 2

enhances phase stability by reducing direct contact with the electrolyte... reducing irreversible reactions

Methodology Applied

Scientific EffectChemical isolation:

Implementation Method 3

maintaining performance... improving ion transfer and conductivity

Methodology Applied

Scientific EffectIon diffusion: Diffusion

Data Source

PatentEP3875434B1Composite positive electrode active material for lithium secondary battery, preparation method thereof, and lithium secondary battery including positive electrode including the same

Publication Date: 2024.11.13 SAMSUNG SDI CO LTD

Figure 1A~1B
Figure 1C~1D
Figure 1E

AI summary

This application relates to a composite positive electrode active material for a lithium secondary battery. The composite positive electrode active material includes a nickel-based active material and a cobalt-boron compound-containing coating layer formed on a surface of the nickel-based active material. The application also relates to a method of preparation of the composite positive electrode active material. The application further relates to a lithium secondary battery including a positive electrode containing the composite positive electrode active material.