Nickel-Rich Positive Electrode Solid Electrolyte Layer

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Solution Overview

Problem

Nickel-rich ternary positive electrode active materials in lithium secondary batteries face challenges with low life characteristics and thermal stability, despite attempts to inhibit side reactions with electrolytes through surface coatings.

Innovation Solution

A positive electrode design for lithium secondary batteries incorporating a first nickel-rich ternary active material layer and a second active material layer with a solid electrolyte, which acts as a cushioning material to prevent direct contact with the electrolyte, thereby enhancing thermal stability and life characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If nickel-rich ternary positive electrode active material is used to achieve high energy density, then the energy density is improved, but the life characteristics and thermal stability deteriorate

Engineering Contradiction:

Improveenergy densityVSAvoidlife characteristics

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

A solid electrolyte layer is introduced as an intermediary between the nickel-rich ternary positive electrode active material and the liquid electrolyte. This solid electrolyte layer prevents direct contact and harmful side reactions between the nickel-rich material and the liquid electrolyte, thereby improving life characteristics and thermal stability while maintaining the high energy density benefits of the nickel-rich material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The positive electrode is designed as a composite structure combining nickel-rich ternary active material with a solid electrolyte layer. This composite structure leverages the high energy density of the nickel-rich material while the solid electrolyte component provides protective functions, creating a synergistic system that achieves both high energy density and improved reliability.

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If nickel-rich ternary positive electrode active material is used to achieve high energy density, then the energy density is improved, but the thermal stability deteriorates

Engineering Contradiction:

Improveenergy densityVSAvoidthermal stability

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The solid electrolyte layer serves as a thermal barrier and intermediary protective layer between the nickel-rich ternary active material and the liquid electrolyte. This layer prevents direct thermal and chemical interactions that could lead to thermal runaway, thereby improving thermal stability while allowing the nickel-rich material to maintain its high energy density characteristics.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solid electrolyte layer creates an inert protective environment around the nickel-rich ternary active material, isolating it from the liquid electrolyte and preventing exothermic side reactions. This inert barrier enhances thermal stability by preventing uncontrolled thermal reactions while preserving the high energy density of the nickel-rich material.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Reliability

If oxide coating is applied to inhibit side reactions, then life characteristics are improved, but thermal stability remains low

Engineering Contradiction:

Improvelife characteristicsVSAvoidthermal stability

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The invention changes the material parameter from conventional oxide coatings to a solid electrolyte layer with different functional properties. The solid electrolyte layer not only provides surface protection like oxide coatings but also offers enhanced thermal stability through its inherent material properties and ability to prevent direct contact between the nickel-rich material and liquid electrolyte, thereby simultaneously improving both life characteristics and thermal stability.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20220293930A1Positive Electrode for Lithium Secondary Battery, Method for Manufacturing the Same, and Lithium Secondary Battery Including the Same

Publication Date: 2022.09.15 LG ENERGY SOLUTION LTD

AI summary

The present disclosure relates to a positive electrode for a lithium secondary battery, including a first positive electrode active material layer including a nickel-rich first positive electrode active material and a second positive electrode active material layer including a solid electrolyte and a second positive electrode active material. The positive electrode for a lithium secondary battery shows improved life characteristics and heat stability by virtue of the introduction of the second positive electrode active material layer.