Composite-Coated LiCoO2 Cathodes for Stable High-Voltage Cycling

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Solution Overview

Problem

Lithium cobalt oxide cathode materials in lithium-ion batteries face thermodynamic limitations, leading to cell degradation and safety concerns when operating at higher voltages, which restricts the extraction of full capacity and poses safety risks.

Innovation Solution

A particulate composite material is developed, comprising a lithium cobalt oxide core coated with lithium manganese nickel cobalt oxide and an inert stabilization nanocoating, which enhances cycling stability at high voltages by forming a synergistic stabilization effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium cobalt oxide is operated at higher voltages to extract full capacity, then energy density is improved, but cell degradation and safety issues worsen

Engineering Contradiction:

Improveenergy densityVSAvoidcell degradation

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A coating layer comprising lithium manganese nickel cobalt oxide and an inert stabilization nanocoating is applied to the lithium cobalt oxide particles. This coating acts as an intermediary between the high-voltage operating conditions and the lithium cobalt oxide core, enabling stable operation at higher voltages (4.47V to 2.5V) while preventing direct degradation of the cathode material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a composite structure where a lithium cobalt oxide core is coated with lithium manganese nickel cobalt oxide and an inert stabilization nanocoating. This composite coating system combines the high energy density benefits of lithium cobalt oxide with the stability and safety of the coating materials, achieving both high energy density and improved reliability.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If lithium cobalt oxide is operated at higher voltages to increase capacity extraction, then energy output is improved, but safety concerns worsen

Engineering Contradiction:

Improveenergy outputVSAvoidsafety concerns

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The coating layer serves as a protective intermediary that allows the lithium cobalt oxide to operate at higher voltages for increased energy output while isolating it from harmful conditions that would compromise safety. The inert stabilization nanocoating specifically addresses safety concerns by providing a stable barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The coating materials, particularly the inert stabilization nanocoating, convert the potentially harmful high-voltage operating conditions into beneficial stable operation. The coating transforms what would be degradation-inducing conditions into opportunities for high energy output with enhanced safety.

Inventive Principle:

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

3Duration of action of stationary object

If a coating is applied to lithium cobalt oxide to improve stability, then cycling stability is improved, but device complexity increases

Engineering Contradiction:

Improvecycling stabilityVSAvoidstructure complexity

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The coating structure uses a nested approach where the lithium manganese nickel cobalt oxide layer is embedded within or followed by an inert stabilization nanocoating. This nested structure provides multiple stabilization functions in a compact configuration, improving cycling stability while minimizing the increase in structural complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The composite coating system combines lithium manganese nickel cobalt oxide with an inert stabilization nanocoating to achieve enhanced cycling stability. This composite approach provides synergistic effects where the combination of materials delivers superior stability compared to single-material coatings, justifying the increased complexity through performance benefits.

Inventive Principle:

Principle #40Composite materials

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 achieves stable cycling at higher voltages, increasing specific capacity and energy output while maintaining thermal stability, thus addressing the limitations of lithium cobalt oxide and improving battery performance.

Implementation Method 1

Methodology Applied

Scientific EffectSynergistic stabilization:

Implementation Method 2

The composite material achieves stable cycling at higher voltages, increasing specific capacity and energy output while maintaining thermal stability

Methodology Applied

Scientific EffectThermal stability:

Data Source

PatentUSRE49980E1Positive electrode active materials with composite coatings for high energy density secondary batteries and corresponding processes

Publication Date: 2024.05.21 IONBLOX INC

AI summary

A composite coated form of lithium cobalt oxide is described that can achieve improved cycling at higher voltages. Liquid phase and combined liquid and solid phase coating processes are described to effectively form the composite coated powders. The improved cycling positive electrode materials can be effectively combined with either graphitic carbon negative electrode active materials or silicon based high capacity negative electrode active materials. Improved battery designs can achieve very high volumetric energy densities in practical battery formats and with reasonable cycling properties.