Lithium Nickel Composite Oxide Coated with Lithium Metal Phosphate
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Solution Overview
Problem
Existing lithium secondary batteries face challenges with thermal stability and capacity retention during repeated charging and discharging, particularly with positive active materials like LiCoO2, which are expensive and have supply issues, and other materials lacking satisfactory state of charge, recovery charge, and thermal stability.
Innovation Solution
A positive active material is developed comprising a lithium nickel-based composite oxide with a composite coating layer of lithium metal phosphate and metal phosphate, formed through a method involving mixing, stirring, and heat treatment between 300° C to 800° C, enhancing thermal stability and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium cobalt oxide (LiCoO2) is used as positive active material, then high discharge voltage and energy density are achieved, but manufacturing cost increases and supply stability deteriorates
Solution Approach 1:
The patent replaces expensive lithium cobalt oxide with lithium nickel-based composite oxide that is cheaper and more readily available, achieving cost reduction while maintaining performance through surface coating modification
Solution Approach 2:
The patent creates a composite structure by coating lithium metal phosphate and metal phosphate on the surface of lithium nickel-based composite oxide particles, combining the high capacity of nickel-based materials with the stability of phosphate coatings
2Ease of manufacture
If lithium nickel-based composite oxide is used as positive active material, then manufacturing cost is reduced, but thermal stability deteriorates
Solution Approach 1:
The patent forms a composite coating layer containing lithium metal phosphate and metal phosphate on the surface of lithium nickel-based composite oxide particles, combining the cost advantages of nickel-based materials with the thermal stability of phosphate coatings
Solution Approach 2:
The patent applies surface coating specifically on the outer surface of the active material particles, providing localized thermal stability protection where it is most needed during charging and discharging processes
3Device complexity
If conventional positive active materials are used, then manufacturing simplicity is maintained, but capacity retention during repeated charging and discharging deteriorates
Solution Approach 1:
The patent creates a composite coating layer with lithium metal phosphate and metal phosphate on lithium nickel-based composite oxide, providing enhanced capacity retention through the synergistic effects of the composite structure
Solution Approach 2:
The patent pre-coats the active material particles with protective phosphate layers before electrode fabrication, preventing capacity degradation from the outset during subsequent charging and discharging cycles
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 provides a lithium battery with high thermal stability and minimal capacity degradation, maintaining high discharge and charge capacity even after repeated cycles, while reducing manufacturing costs and ensuring a stable supply of materials.
Implementation Method 1
heat treating the crystals at a temperature in a range from about 300° C. to about 800° C., wherein a composite coating layer that includes the lithium metal phosphate and the metal phosphate are coated on a surface of the lithium nickel-based composite oxide
Data Source
AI summary
In one aspect, a positive active material is provided that may have increased thermal stability and resistance to capability deterioration due to repeated charging and discharging, a method of manufacturing the same, and a lithium battery that includes the positive active material.