Mixed Oxide Coatings for Cathode Materials

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Solution Overview

Problem

Lithium-ion batteries face challenges in maintaining high energy density and cycle life due to chemical reactions between cathode materials and electrolytes, leading to energy loss and capacity fade, which conventional aluminum oxide coatings partially address but at the cost of energy density.

Innovation Solution

The use of mixed oxide coatings such as Al2O3 and ZrO2, or Al2O3 and La2O3, and complex oxides like ZnAl2O4 on cathode active materials to enhance discharge capacity, average voltage, and energy retention, while minimizing capacity fade.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aluminum oxide coating is applied to cathode particles, then the reaction between cathode and electrolyte is mitigated and transition metal dissolution is prevented, but energy density is reduced

Engineering Contradiction:

Improvecycle lifeVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the coating material parameters from conventional aluminum oxide to complex oxides with specific compositions (e.g., Li0.8Co0.1Mn0.05Ni0.05O2, Li1.03Ni0.8Co0.1Mn0.05O2) and controlled thickness (1-10 nm), achieving improved cycle life while maintaining higher energy density through optimized stoichiometry and elemental composition

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite oxide coatings combining multiple elements (Li, Co, Mn, Ni, Al, Mg, Ti, Zr, Ta, W) in specific ratios to create multi-functional coating layers that simultaneously provide protection against electrolyte reaction and maintain electrochemical performance, resolving the contradiction between reliability and energy density

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If conventional coatings are applied to cathode materials, then stability is improved, but energy retention and discharge capacity are reduced

Engineering Contradiction:

Improvechemical stabilityVSAvoidenergy retention

Core Design Contradiction:

Stability of the object's compositionVSDuration of action of moving object

Solution Approach 1:

The patent optimizes coating parameters including thickness (1-10 nm), stoichiometry (controlled deviation from ideal ratios), and elemental composition to achieve a balance where the coating provides sufficient chemical stability while allowing adequate lithium ion transport, thereby maintaining high energy retention over cycles

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The coating is applied as a thin surface layer (1-10 nm) that provides localized protection at the cathode-electrolyte interface while minimizing impact on the bulk material's electrochemical properties, enabling improved stability without significant loss of energy retention

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11695108B2Oxide mixture and complex oxide coatings for cathode materials

Publication Date: 2023.07.04 UCHICAGO ARGONNE LLC

AI summary

Cathode active materials are provided. The cathode active material can include a plurality of cathode active compound particles. A coating is disposed over each of the cathode active compound particles. The coating can include at least one of ZrO2, La2O3, a mixture of Al2O3 and ZrO2 or a mixture of Al2O3 and La2O3. The battery cells that include the cathode active material are also provided.