Dual-Coated Nickel-Rich Cathode Powders for Stable Li-Ion Transport

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Solution Overview

Problem

Nickel-rich lithium transition metal oxide cathode active materials in batteries face challenges with chemical and electrochemical stability, particularly due to limitations in Li ion conductivity and phase transitions caused by conventional binary oxide coatings like Al2O3, which consume Li ions and increase impedance.

Innovation Solution

A dual coating approach using a nickel-rich lithium transition metal oxide with a first coating material and a second lithium metal oxide coating that overcoats or fills voids in the first coating, providing enhanced chemical stability and Li+ ionic conductivity, and is more stable than Al2O3 and LiNbO3 coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If conventional binary oxide coatings like Al2O3 are used on nickel-rich lithium transition metal oxide, then chemical stability is improved, but Li ion conductivity deteriorates and impedance increases

Engineering Contradiction:

Improvechemical stabilityVSAvoidLi ion conductivity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies composite coating materials consisting of lithium transition metal oxides (such as LiNbO3, Li2SiO3, Li2GeO3) combined with other metal oxides. These composite coatings provide both chemical stability and Li ion conductivity, resolving the contradiction between protection and ion transport that plagues conventional single-material coatings like Al2O3.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the coating material from conventional binary oxides to lithium-containing transition metal oxides with specific stoichiometries. This parameter change enables the coating to simultaneously achieve chemical stability and maintain Li ion conductivity, preventing the impedance increase associated with conventional coatings.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If nickel-rich lithium transition metal oxide is used to increase capacity, then energy density is improved, but chemical and electrochemical stability deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidchemical stability

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The patent uses lithium-containing transition metal oxide coatings (such as LiNbO3, Li2SiO3, Li2GeO3) that form protective composite structures on nickel-rich cathode surfaces. These coatings provide chemical stability and electrochemical performance, enabling the use of high-nickel content materials for increased energy density without sacrificing stability.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS20230378440A1Protective coatings for cathode powders

Publication Date: 2023.11.23 RIVIAN HOLDINGS LLC

AI summary

A cathode active material comprising: a nickel-rich lithium transition metal oxide; a first coating material on a surface of the nickel-rich lithium transition metal oxide; and a second coating material comprising a lithium metal oxide; wherein the second coating material overcoats the first coating material, fills in voids of the first coating material on the surface of the nickel-rich lithium transition metal oxide, or both overcoats the first coating material and fills in voids of the first coating material on the surface of the nickel-rich lithium transition metal oxide, and the second coating material is different from the first coating material and the nickel-rich lithium transition metal oxide.