Lithium-Rich Composite Cathode Coating for Electrolyte Stability

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Solution Overview

Problem

Existing cathode lithium-supplementing additives in lithium-ion batteries suffer from unsatisfactory stability and high activity at the interface with the electrolyte, leading to issues with initial coulombic efficiency and battery capacity.

Innovation Solution

A lithium-rich composite material is developed, comprising a core with a dense hydrophobic layer coated on it. The dense hydrophobic layer is made of a polyanionic electrochemically active material, such as phosphate electrode active materials, mixed with an electronic conductive agent, which enhances the layer's compactness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a carbon coating layer is applied to lithium ferrite material to isolate the ambient environment, then the stability of the material is improved, but the ion conductivity is reduced due to increased ion conduction path length

Engineering Contradiction:

Improvematerial stabilityVSAvoidion conductivity reduction

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies a composite coating structure consisting of an inner amorphous carbon layer and an outer lithium phosphate layer. The amorphous carbon layer provides environmental isolation and stability, while the lithium phosphate layer restores ion conductivity by providing lithium ion diffusion channels. This composite structure resolves the contradiction by combining materials with complementary properties.

Inventive Principle:

Principle #40Composite materials

2Reliability

If conventional coating methods are used to protect lithium-rich material, then environmental isolation is achieved, but residual alkali remains in the coating layer or at the interface, making processing difficult

Engineering Contradiction:

Improveenvironmental isolationVSAvoidprocessing difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The lithium phosphate layer serves as an intermediary between the lithium-rich core material and the external environment. It not only provides environmental isolation but also acts as a buffer that eliminates residual alkali issues, facilitating easier processing while maintaining protective functions.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the coating layer is made denser to improve isolation, then environmental stability is enhanced, but the interface activity with electrolyte increases, causing side reactions

Engineering Contradiction:

Improveenvironmental isolationVSAvoidside reactions with electrolyte

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent creates different functional zones within the coating structure: the inner amorphous carbon layer provides dense environmental isolation, while the outer lithium phosphate layer provides controlled interface properties that reduce side reactions with electrolyte. Each layer has optimized local properties suitable for its specific function.

Inventive Principle:

Principle #3Local quality

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 lithium-rich composite material achieves improved stability and reduced side reactions with the electrolyte, resulting in enhanced initial coulombic efficiency, battery capacity, and cycle performance of lithium-ion batteries.

Implementation Method 1

a dense hydrophobic layer coated on the core... the dense hydrophobic layer... isolating the core from the ambient environment, preventing, for example, water and carbon dioxide in the ambient environment from contacting with the core

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 2

The material of the dense hydrophobic layer comprises a polyanionic electrochemically active material... the polyanionic electrochemically active material is a phosphate electrode active material

Methodology Applied

Scientific EffectPolyanionic effect:

Implementation Method 3

a material of the dense hydrophobic layer comprises a polyanionic electrochemically active material... mixed with an electronic conductive agent, which enhances the layer's compactness and stability

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 4

achieves improved stability and reduced side reactions with the electrolyte... The dense hydrophobic layer... isolating the core from the ambient environment

Methodology Applied

Scientific EffectInterface passivation:

Data Source

PatentUS20250046803A1Lithium-rich composite material, preparation method thereof, and application thereof

Publication Date: 2025.02.06 SHENZHEN INNOVAZONE TECH CO LTD

AI summary

Disclosed are a lithium-rich composite material, and a preparation method thereof, and an application thereof. The lithium-rich composite material includes a core and a dense hydrophobic layer coated on the core. The core includes a lithium-rich material, and a material of the dense hydrophobic layer includes a polyanionic electrochemically active material, and the polyanionic electrochemically active material is a phosphate electrode active material. The lithium-rich composite material of the present application includes a dense hydrophobic layer, which has high compactness, low content of residual alkali and high chemical stability when being in contact with an electrolyte. In addition, the preparation method of the lithium-rich composite material can ensure that the structure and the electrochemical performances of the prepared lithium-rich composite material are stable; moreover, the efficiency is high and the production cost is saved.