Spherical Cathode Material for High-Temperature Lithium-Ion Batteries
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Solution Overview
Problem
Current lithium-ion battery cathode materials lack specific morphological and structural characteristics for high specific capacity, stability, safety, and cycling performance at elevated temperatures, with unclear guidelines on optimal morphology and preparation methods.
Innovation Solution
A spherical or spherical-like layered cathode material with the chemical formula LiaNixCoyMnzMbO2, where 1.02≤a≤1.20, 0.0≤b≤0.5, 0.30≤x≤0.60, 0.20≤y≤0.40, 0.05≤z≤0.50, and M includes elements like Mg, Ti, Al, Zr, Y, Co, Mn, Ni, Ba, and rare earth elements, is developed, featuring a rounded surface and agglomerated primary particles for improved structural integrity and industrial production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional layered lithium nickel composite oxide is used to achieve high specific capacity, then the structure becomes fragile when delithiated amount is large, causing atomic rearrangement and reconstruction at high temperature and pressure
Solution Approach 1:
The patent uses composite materials by combining lithium nickel composite oxide with lithium manganese composite oxide in specific ratios (mole ratio 95:5 to 50:50). This composite structure leverages the high specific capacity of lithium nickel composite oxide while the lithium manganese composite oxide component provides structural stability, preventing atomic rearrangement and reconstruction during delithiation and at high temperatures.
Solution Approach 2:
The patent applies local quality by creating a core-shell structure where the inner core consists of lithium nickel composite oxide particles providing high capacity, and the outer shell consists of lithium manganese composite oxide coating that provides structural stability and protection. This local differentiation allows each region to fulfill its specific function optimally.
2Stability of the object's composition
If bulk doping is applied to suppress structural change, then reversibility is enhanced, but charge transfer resistance increases during cycling
Solution Approach 1:
The patent applies local quality by concentrating the doping elements (Mg, Ti, Al, Zr, Y, Ba, rare earth elements) specifically in the shell layer surrounding the lithium nickel composite oxide core. This localized doping provides structural stability at the interface where it is most needed, while the bulk core maintains its high capacity characteristics and good charge transfer properties.
Solution Approach 2:
The patent uses composite materials by combining doped lithium manganese composite oxide shell with undoped or lightly doped lithium nickel composite oxide core. This composite structure allows the shell to provide structural stability and suppress structural changes during cycling, while the core maintains high reversibility and low charge transfer resistance.
3Reliability
If surface coating modification is applied to avoid direct contact with electrolyte, then safety and cycle stability are increased, but manufacturing complexity increases
Solution Approach 1:
The patent merges the coating process with the sintering process by adding lithium manganese composite oxide precursor to the slurry mixture before sintering. This allows the coating layer to form in-situ during the standard sintering process rather than requiring separate coating steps, thereby increasing cycle stability while minimizing manufacturing complexity.
Solution Approach 2:
The patent uses parameter changes by controlling the sintering temperature (700-1080°C), time (6-30 hours), and atmosphere (air or oxygen) to simultaneously achieve core formation, shell coating, and proper phase structure. By optimizing these parameters, the patent achieves effective surface modification without adding complex process steps.
4Ease of manufacture
If spherical morphology is adopted to improve industrial production, then structural integrity is enhanced, but control over crystalline grain size and phase requires precise parameter optimization
Solution Approach 1:
The patent uses parameter changes by systematically optimizing sintering temperature (700-1080°C), sintering time (6-30 hours), and atmosphere (air or oxygen) to achieve the desired spherical morphology and crystalline grain size (1000-3000 Å). These parameter adjustments allow control over material properties while maintaining a simple, industrially scalable process.
Solution Approach 2:
The patent applies local quality by controlling the morphology of primary particles to be spherical while allowing secondary particles to form through natural agglomeration. This local control over primary particle shape provides structural integrity and ease of handling, while the secondary particle structure develops naturally during sintering, reducing manufacturing complexity.
Data Source
AI summary
The present invention relates to a spherical or spherical-like cathode material for lithium-ion battery and a lithium-ion battery. The chemical formula of the cathode material is LiaNixCoyMnzMbO2, wherein: 1.02≤a≤1.20; 0.0≤b≤0.5; 0.30≤x≤0.60; 0.20≤y≤0.40; 0.05≤z≤0.50; x+y+z=1; M is one or two or more selected from the group consisting of Mg Ti Al Zr Y Co Mn Ni Ba and rare earth elements. Under the scanning electron microscope, the cathode material comprises primary particles with a morphology of spherical or spherical shape, and secondary particles agglomerated by the primary particles. The number percentage of the secondary particles agglomerated by the primary particles is less than or equal to 30%. The lithium battery prepared by the obtained cathode material has high specific capacity, high temperature stability, excellent safety and cycling performance at high temperature, and the preparation method thereof is simple and the cost is relatively low.