Nickel-Based Cathode Particle Structure for Longer Battery Cycle Life

Solution Overview

Problem

Rechargeable lithium batteries face a challenge where increased capacity leads to decreased cycle-life, and nickel-based lithium metal oxides suffer from deteriorated charge/discharge efficiency and cycle-life due to side-reactions with the electrolyte.

Innovation Solution

A positive electrode for rechargeable lithium batteries is developed, comprising small particle diameter monolith particles and large particle diameter secondary particles, both made of nickel-based lithium metal oxides, with a specific X-ray diffraction peak intensity ratio (I(003)/I(104)) of greater than or equal to 3, which improves cycle-life and capacity while maintaining high temperature stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If nickel-based lithium metal oxides are used to increase battery capacity, then capacity characteristics are improved, but charge/discharge efficiency and cycle-life are deteriorated due to side-reactions with the electrolyte

Engineering Contradiction:

Improvebattery capacityVSAvoidcycle-life

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the central core particles have high nickel content (90-98 mol%) for maximum capacity, while the surface shell has reduced nickel content and increased stability elements to minimize side-reactions with the electrolyte. This spatial differentiation of material composition allows the interior to maximize capacity while the exterior protects against degradation, resolving the contradiction between high capacity and long cycle-life.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs composite materials by combining nickel-based lithium metal oxide with other metal oxides (such as cobalt, manganese, aluminum, or titanium) to form a multi-component system. The composite structure leverages the high capacity of nickel while incorporating stabilizing elements that reduce electrolyte side-reactions, thereby achieving both high capacity retention and improved cycle-life through synergistic material combination.

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If nickel-based lithium metal oxides are used to increase battery capacity, then capacity characteristics are improved, but charge/discharge efficiency is deteriorated due to side-reactions with the electrolyte

Engineering Contradiction:

Improvebattery capacityVSAvoidcharge/discharge efficiency

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The core-shell structure implements local quality by concentrating high nickel content in the core for maximum lithium storage capacity while placing a protective shell with lower nickel content and higher stability elements at the surface. This spatial differentiation ensures that charge/discharge reactions occur primarily at the stable shell interface with the electrolyte, minimizing side-reactions and maintaining high charge/discharge efficiency while preserving the high capacity of the nickel-rich core.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces an intermediary shell layer that acts as a mediator between the high-nickel core and the electrolyte. This shell layer facilitates efficient lithium ion transport while simultaneously protecting the core from direct contact with the electrolyte, thereby maintaining high charge/discharge efficiency and reducing harmful side-reactions through the intermediary protective function.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Quantity of substance

If high nickel content is used to achieve high capacity, then capacity characteristics are improved, but stability against side-reactions with electrolyte is reduced

Engineering Contradiction:

Improvebattery capacityVSAvoidside-reactions with electrolyte

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a core-shell structure where the central core particles have high nickel content (90-98 mol%) for maximum capacity, while the surface shell has reduced nickel content and increased stability elements to minimize side-reactions with the electrolyte. This spatial differentiation of material composition allows the interior to maximize capacity while the exterior protects against degradation, resolving the contradiction between high capacity and long cycle-life.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces an intermediary shell layer that acts as a mediator between the high-nickel core and the electrolyte. This shell layer facilitates efficient lithium ion transport while simultaneously protecting the core from direct contact with the electrolyte, thereby maintaining high charge/discharge efficiency and reducing harmful side-reactions through the intermediary protective function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250125339A1Positive electrode for rechargeable lithium battery, method of preparing the same, and rechargeable lithium battery including the same

Publication Date: 2025.04.17 SAMSUNG SDI CO LTD

AI summary

A positive electrode for a rechargeable lithium battery includes a positive active material including small particle diameter monolith particles having a particle diameter of about 1 μm to about 8 μm and including a first nickel-based lithium metal oxide, and large particle diameter secondary particles having a particle diameter of about 10 μm to about 20 μm and including a second nickel-based lithium metal oxide. An X-ray diffraction peak intensity ratio (I(003)/I(104)) of the positive electrode is greater than or equal to about 3. A rechargeable lithium battery includes the positive electrode.