Ni-Rich Cathode Coating with Co-Oxide Islands for Lithium Exchange

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Lithium ion batteries, particularly those with Ni-rich electrode active materials, face issues with undesired reactions on the electrode surface, such as electrolyte decomposition, which current coatings and surface treatments have not adequately addressed without hindering lithium exchange during charging and discharging.

Innovation Solution

A process involving treating an electrode active material with a carbonyl compound of Co and then an oxidant to create a partially coated material with excellent electrochemical properties, specifically forming island-like structures of Co-oxides on the surface, enhancing stability against oxidation at 4.3V vs. Li/Li+.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electrode active material is coated with aluminium oxide or calcium oxide to protect the surface, then the stability against oxidation is improved, but the lithium exchange during charging and discharging is hindered

Engineering Contradiction:

Improvestability against oxidationVSAvoidlithium exchange rate

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies a non-uniform coating distribution where cobalt oxide forms island-like structures concentrated at grain boundaries rather than uniform coverage. This local concentration provides oxidation protection where most needed (at interfaces) while leaving bulk surface areas open for lithium exchange, resolving the contradiction between protection and reactivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite surface structure combining cobalt oxide protective islands with exposed electrode active material surfaces. This composite architecture allows simultaneous presence of protective regions (cobalt oxide) and reactive regions (exposed material), enabling both oxidation resistance and efficient lithium exchange

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If the electrode active material is washed with water to remove free LiOH or Li2CO3, then the surface purity is improved, but the electrochemical properties do not improve in some instances

Engineering Contradiction:

Improvesurface purityVSAvoidelectrochemical performance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the surface composition parameter by introducing cobalt oxide species through carbonyl compound treatment and oxidation, transforming the surface from containing harmful LiOH/Li2CO3 to containing protective cobalt oxide. This parameter change (compositional transformation) simultaneously achieves purity improvement and electrochemical performance enhancement

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent converts the harmful effect of surface impurities (LiOH, Li2CO3) into a beneficial protective layer (cobalt oxide). Instead of merely removing contaminants, the process transforms the surface chemistry to create a protective coating that actively prevents oxidation and enhances performance, turning a problematic surface into an asset

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If an additional calcination step is performed to adjust cobalt concentration on grain boundaries, then the electrochemical properties are improved, but the energy consumption increases significantly

Engineering Contradiction:

Improveelectrochemical propertiesVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent performs preliminary cobalt compound deposition on the electrode active material surface before final battery assembly. By pre-loading cobalt compounds and using mild oxidation treatment instead of high-temperature calcination, the process achieves the desired cobalt concentration at grain boundaries with significantly reduced energy input, resolving the contradiction between performance optimization and energy efficiency

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 process results in electrode active materials with improved stability and electrochemical performance, maintaining effective lithium exchange while preventing surface reactions, leading to enhanced battery discharge behavior and cycling stability.

Implementation Method 1

treating said electrode active material with at least one carbonyl compound of Co

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

treating the material obtained in step (b) with an oxidant

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11984578B2Process for making an at least partially coated electrode active material

Publication Date: 2024.05.14 BASF SE

AI summary

Process for making an at least partially coated electrode active material wherein said process comprises the following steps: (a) Providing an electrode active material according to general formula Li1+xTM1−xO2, wherein TM is a combination of Ni and Co or Ni and Al and, optionally, Mn, and, optionally, at least one metal selected from Ga, Nb, Ta, Mg, Mo, B, Sn, V, W, Ti and Zr, and x is in the range of from zero to 0.2, (b) treating said electrode active material with at least one carbonyl compound of Co, and (c) treating the material obtained in step (b) with an oxidant.