Single-Particle Cathode Active Material for Stable High-Energy Batteries
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Solution Overview
Problem
Existing lithium nickel composite metal oxides used in lithium secondary batteries face challenges in achieving excellent volumetric energy density and life characteristics due to instability, particularly when subjected to high temperatures and electrolyte reactions.
Innovation Solution
A positive electrode active material comprising a first lithium composite transition metal oxide in the form of single particles, with specific geometric and compositional characteristics, is prepared through a controlled sintering process, optionally combined with a second lithium composite transition metal oxide, to enhance stability and reduce reactivity with electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel composite metal oxide is used to achieve high reversible capacity, then battery capacity is improved, but thermal stability deteriorates
Solution Approach 1:
The patent uses composite materials by combining lithium nickel composite metal oxide with lithium cobalt composite metal oxide or lithium manganese composite metal oxide. This creates a composite positive electrode active material that leverages the high capacity of nickel-based materials while the cobalt or manganese components provide thermal stability, thus resolving the contradiction between high reversible capacity and thermal stability.
2Use of energy by moving object
If lithium cobalt composite metal oxide is used to achieve high operating voltage and excellent capacity, then energy density is improved, but cost increases and thermal properties deteriorate
Solution Approach 1:
The patent creates a composite material system where lithium cobalt composite metal oxide is combined with lithium nickel composite metal oxide. The lithium cobalt component provides high operating voltage and good thermal stability, while the lithium nickel component contributes high capacity. This composite approach maintains energy density while improving thermal properties and reducing cost compared to pure lithium cobalt oxide.
3Quantity of substance
If nickel content is increased to achieve large capacity, then battery capacity is improved, but thermal stability and safety deteriorate
Solution Approach 1:
The patent employs composite materials by formulating a positive electrode active material containing both lithium nickel composite metal oxide (providing high capacity) and lithium cobalt composite metal oxide or lithium manganese composite metal oxide (providing thermal stability). This composite structure allows high nickel content for large capacity while the other metal oxides suppress thermal runaway and improve safety.
4Use of energy by moving object
If particle size and morphology are optimized to improve volumetric energy density, then energy density is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size, shape, and morphology of the composite positive electrode active material. By controlling synthesis parameters such as sintering temperature, time, and atmosphere, the patent achieves specific particle characteristics that maximize volumetric energy density while maintaining a manufacturable process through systematic parameter optimization rather than complex multi-step procedures.
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 proposed active material exhibits improved volumetric energy density and life characteristics by minimizing electrolyte reactions and maintaining structural integrity during charge and discharge cycles.
Implementation Method 1
A positive electrode active material comprising a first lithium composite transition metal oxide in the form of single particles, with specific geometric and compositional characteristics, is prepared through a controlled sintering process
Data Source
Figure 1(A)~1(F)
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AI summary
The present invention relates to a positive electrode active material capable of improving performance of a lithium secondary battery, the positive electrode active material including: a first lithium composite transition metal oxide in a form of a single particle; and optionally a second lithium composite transition metal oxide in a form of a single particle, wherein the first lithium composite transition metal oxide in the form of a single particle includes 30 or less disk-type primary particles, wherein each of the disk-type primary particles is a primary particle observed from a scanning electron microscope (SEM) image of a surface or cross section of the positive electrode active material, wherein, when an imaginary tangent line with the most contact points is drawn to each of two boundary lines of the primary particle present within an angle of 45° or less based on a long diameter direction and one imaginary line crossing the two tangent lines is drawn, interior angles of same side are at least 150° and at most 210°, and an aspect ratio of (major axis/minor axis) is 1.5 or more, wherein the positive electrode active material includes the first lithium composite transition metal oxide in an amount of 20 vol% to 100 vol% based on a total volume of the positive electrode active material, a method for preparing the positive electrode active material, and a positive electrode and lithium secondary battery including the positive electrode active material.