High-Nickel Cathode Composition for Cycle Life and Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Rechargeable lithium batteries with high nickel-based positive electrodes face issues of reduced long-term cycle-life, thermal stability, and performance due to increased nickel content, which also raises concerns about cobalt content and structural stability.
Innovation Solution
A positive electrode for rechargeable lithium batteries comprising a current collector with a positive electrode active material layer, where the active material consists of 75-100 wt% lithium nickel-based composite oxide with a nickel content of ≥70 mol% in the form of single particles and 0-25 wt% in the form of secondary particles, enhancing crystal alignment and structural stability through X-ray diffraction analysis and specific particle sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel content (≥70 mol%) is used in lithium nickel-based composite oxide to increase energy density, then energy density and capacity are improved, but long-term cycle-life and thermal stability deteriorate
Solution Approach 1:
The patent changes the particle morphology parameter from aggregated secondary particles to single particles, and controls the crystallite size parameter at 10-50 nm. These parameter changes in the material structure improve structural stability and reduce cation mixing, thereby maintaining long-term cycle-life while using high nickel content (≥70 mol%) for high energy density
Solution Approach 2:
The patent creates a composite material system consisting of lithium nickel-based composite oxide with specific single-particle morphology and controlled crystallite size, combined with lithium metal oxide. This composite structure achieves both high energy density from high nickel content and improved reliability through reduced cation mixing and enhanced structural stability
2Use of energy by moving object
If high nickel content (≥70 mol%) is used to increase energy density, then capacity is improved, but thermal stability deteriorates
Solution Approach 1:
The patent changes the particle morphology to single particles and controls crystallite size at 10-50 nm, which suppresses crack generation during cycling and improves thermal stability. This allows the use of high nickel content (≥70 mol%) for high capacity without suffering from thermal runaway issues
3Ease of manufacture
If cobalt content is minimized or eliminated to reduce cost, then manufacturing cost is improved, but structural stability and performance deteriorate
Solution Approach 1:
The patent changes the particle morphology to single particles and controls crystallite size at 10-50 nm, which inherently improves structural stability. This allows cobalt-free or low-cobalt lithium nickel-based composite oxide to achieve both low cost and high structural stability, eliminating the need for expensive cobalt while maintaining performance
4Ease of manufacture
If conventional secondary particle structure is used, then ease of manufacture is improved, but structural stability and charge/discharge efficiency deteriorate due to cation mixing
Solution Approach 1:
The patent changes the particle morphology from aggregated secondary particles to single particles with controlled crystallite size (10-50 nm). This parameter change significantly reduces cation mixing between Li and Ni sites, improving structural stability and charge/discharge efficiency while maintaining ease of manufacture through conventional sintering processes
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
This configuration improves charge/discharge efficiency, cycle-life characteristics, and thermal stability while reducing costs by using cobalt-free materials, achieving high capacity and energy density with enhanced structural stability.
Implementation Method 1
a positive electrode for a rechargeable lithium battery... comprising a current collector and a positive electrode active material layer on the current collector
Implementation Method 2
in an X-ray diffraction analysis of the positive electrode, a ratio of a peak intensity of the (003) plane to a peak intensity of the (104) plane is greater than or equal to about 4.8
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed are a positive electrode for a rechargeable lithium battery and a rechargeable lithium battery comprising the same, the positive electrode for the rechargeable lithium battery comprising a current collector and a positive electrode active material layer on the current collector, wherein the positive electrode active material layer comprises a positive electrode active material, the positive electrode active material comprises about 75 wt% to about 100 wt% of a first positive electrode active material in a form of a single particle and comprising a lithium nickel-based composite oxide having a nickel content of greater than or equal to about 70 mol% relative to the total metal excluding lithium, and about 0 wt% to about 25 wt% of a second positive electrode active material in a form of a secondary particle in which a plurality of primary particles are aggregated and comprising a lithium nickel-based composite oxide, and in an X-ray diffraction analysis of the positive electrode, and a ratio of a peak intensity of the (003) plane to a peak intensity of the (104) plane is greater than or equal to about 4.8.