Coated Cathode Materials for High-Voltage Lithium-Ion Batteries

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Solution Overview

Problem

Lithium-ion batteries face challenges in achieving high-energy density and thermal stability when charging at voltages higher than conventional cut-offs, leading to capacity fade due to non-uniform surface coatings on cathode active materials.

Innovation Solution

A process involving co-precipitation and sintering to form coated cathode active materials with electrochemically inert or active coatings, allowing for precise control of coating layer composition and thickness, ensuring uniform coverage and improved electrochemical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the charge cut-off voltage is raised to enhance energy density, then the energy density is improved, but the thermal stability and cell performance deteriorate

Engineering Contradiction:

Improveenergy densityVSAvoidthermal stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by coating the cathode active material surface with electrochemically inert materials (such as Al2O3, ZrO2, ZnO, AlF3, Ni3(PO4)2, or AlPO4) before the material is exposed to the electrolyte. This pre-coating protects the material from degradation when charged at high voltages above 4.2V, thereby enabling enhanced energy density while maintaining thermal stability and preventing capacity fade.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses an electrochemically inert coating layer as an intermediary between the cathode active material and the electrolyte. This intermediate layer acts as a protective barrier that prevents direct harmful interactions at high voltages, allowing the system to operate at higher charge cut-off voltages (enhancing energy density) while the coating maintains thermal stability and prevents performance deterioration.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If surface coating is applied to improve cycle life and safety, then the cycle life and safety are improved, but the coating uniformity deteriorates

Engineering Contradiction:

Improvecycle lifeVSAvoidcoating uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies self-service by utilizing the cathode active material particles themselves as substrates for the coating process. The particles serve both as the functional material and as the foundation for uniform coating deposition. This self-referential approach ensures that the coating is applied uniformly to all particles, with each particle receiving consistent coverage, thereby achieving both improved cycle life and uniform coating distribution.

Inventive Principle:

Principle #25Self-service

3Object-affected harmful factors

If surface coating is applied to improve safety, then the safety is improved, but the coating uniformity deteriorates, leading to severe capacity fade

Engineering Contradiction:

ImprovesafetyVSAvoidcoating uniformity

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #25Self-service

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 significantly enhanced electrochemical performance and improved cycle life of lithium-ion batteries by ensuring uniform coating and stable operation at higher charge cut-offs.

Implementation Method 1

coating the cathode material precursor with an electrochemically inert coating material precursor by precipitation to form a coated cathode material precursor

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Implementation Method 2

sintering the lithiated or sodiating coated cathode material precursor to form a cathode active material coated with an electrochemically inert material

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS10833321B2Cathode materials for lithium ion batteries

Publication Date: 2020.11.10 UCHICAGO ARGONNE LLC

AI summary

A process of forming a coated cathode active material include preparing a cathode material precursor by co-precipitation; coating the cathode material precursor with an electrochemically inert coating material precursor by precipitation to form a coated cathode material precursor; lithiating the coated cathode material precursor with a lithium source material to form a lithiated coated cathode material precursor; and sintering the lithiated coated cathode material precursor to form a cathode active material coated with an electrochemically inert material.