Lanthanide-Doped Nickel Cathode Material for Low Residual Lithium
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Solution Overview
Problem
The development of lithium secondary batteries with high energy density faces challenges in safety and efficiency due to agglomeration of particles, reduction in productivity, increased residual lithium, and decreased capacity and lifetime, particularly with single crystalline positive electrode active materials.
Innovation Solution
A positive electrode active material for lithium secondary batteries is developed, comprising 60 mol % or more nickel and containing a lanthanide element, with large crystal particles of 1 μm to 10 μm size, achieved through a method involving specific heat treatments and molar ratio control, which accelerates grain growth and suppresses oxygen desorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a single crystalline positive electrode active material is used to improve lifetime characteristics, then lifetime is improved, but particle agglomeration occurs and productivity decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mixing molar ratio of lithium to metals (0.8-1.0) during heat treatment, and by conducting two-stage heat treatment at specific temperature ranges (first heat treatment at 850-950°C, second heat treatment at 700-800°C). These parameter optimizations enable formation of large crystal particles (1-10 μm) with reduced agglomeration, thus improving both lifetime and productivity simultaneously
2Duration of action of stationary object
If a single crystalline positive electrode active material is used to improve lifetime characteristics, then lifetime is improved, but residual lithium increases and capacity decreases
Solution Approach 1:
The patent controls the mixing molar ratio of lithium to metals within 0.8-1.0 during the first heat treatment and 0.95-1.05 during the second heat treatment. This precise parameter control prevents excessive lithium content, reducing residual lithium while maintaining the single crystalline structure needed for improved lifetime and capacity
3Use of energy by moving object
If high energy density is achieved to improve battery performance, then energy density is improved, but safety deteriorates
Solution Approach 1:
The patent uses composite materials by incorporating a lanthanide element (such as cerium, neodymium, or samarium) into the nickel-based active material matrix. This composite structure with large crystal particles (1-10 μm) provides both high energy density through nickel content (60 mol% or more) and improved safety through the stabilizing effect of the lanthanide element and reduced surface impurities
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 solution results in improved lifetime characteristics and reduced residual lithium, enhancing the performance and stability of lithium secondary batteries by maintaining a stable crystal structure and minimizing surface impurities.
Implementation Method 1
grain growth has been accelerated
Implementation Method 2
inhibits oxygen desorption from a surface
Data Source
AI summary
Disclosed are: a positive electrode active material for a lithium secondary battery, the positive electrode active material including a nickel-based active material containing 60 mol % or more of nickel, and including a large crystal particle which has a size of 1 μm to 10 μm and contains a lanthanide element therein; a method of manufacturing the same; and a lithium secondary battery including a positive electrode including the positive electrode active material.