Doped Co3O4 Precursor for Stable High-Voltage Lithium Cobalt Oxide
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Solution Overview
Problem
The challenge is to develop a positive electrode active material for lithium secondary batteries with large particle sizes that maintains structural stability at high voltages, as excessive doping elements inhibit particle growth and reduce stability.
Innovation Solution
A positive electrode active material precursor with primary particles of Co3O4 or CoOOH, doped with 3,000 ppm or more of elements like aluminum, achieving an average particle diameter of 15 μm or more, is prepared through a co-precipitation reaction, which is then mixed with a lithium source to form a lithium cobalt-based oxide with 2,500 ppm or more doping, allowing for stable operation at high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a doping element is added to lithium cobalt oxide to improve structural stability at high voltage, then structural stability is improved, but particle growth is inhibited and particle size remains small
Solution Approach 1:
The patent applies preliminary action by conducting doping during the precursor formation stage (co-precipitation) rather than after particle growth. The doping elements (Al, Ti, Mn, Zr, Mg, Nb, Ca, F, or Ni) are incorporated into the precursor particles before they are converted to lithium cobalt oxide, allowing the doped precursor to serve as a template for subsequent particle growth. This timing enables particle growth to proceed without the strong inhibitory effect that would occur if doping were performed on already-formed particles.
Solution Approach 2:
The patent changes the parameter of doping concentration to an excessive amount (3,000 ppm or more in the precursor, resulting in 2,500 ppm or more in the final product). This excessive doping level, when applied during precursor formation rather than post-synthesis, allows simultaneous achievement of structural stability (requiring high doping content) and particle growth (which would be inhibited by the same high doping content if applied later).
2Quantity of substance
If the voltage is increased to 4.5 V or more to increase battery capacity, then capacity is improved, but structural stability deteriorates due to crystal structure instability
Solution Approach 1:
The patent applies preliminary action by incorporating doping elements during the precursor formation stage, creating a doped precursor that serves as a stable template for subsequent lithium cobalt oxide formation. This early doping ensures that the stabilizing effect is present from the beginning of the material formation process, enabling the final product to maintain structural stability even when charged to high voltages of 4.5 V or more where delithiation-induced instability would normally occur.
Solution Approach 2:
The patent creates a composite material system by incorporating multiple doping elements (Al, Ti, Mn, Zr, Mg, Nb, Ca, F, or Ni) into the lithium cobalt oxide structure. This composite approach, achieved through co-precipitation of doped precursors followed by reaction with lithium sources, produces a material that combines the high capacity characteristics of lithium cobalt oxide with the structural stabilization provided by the dopant elements, enabling stable operation at 4.5 V or higher.
3Stability of the object's composition
If an excessive amount of doping element is used to ensure structural stability, then structural stability is improved, but particle growth is further inhibited making large particle preparation difficult
Solution Approach 1:
The patent applies preliminary action by performing doping during the precursor formation stage through co-precipitation, before the conversion to lithium cobalt oxide. This timing allows the excessive amount of doping element (3,000 ppm or more in precursor) to be uniformly distributed throughout the precursor particles, which then serve as templates for controlled particle growth during subsequent processing. The preliminary doping establishes a stable framework that guides particle growth rather than randomly inhibiting it.
Solution Approach 2:
The patent changes the parameter of doping amount to an excessive level (3,000 ppm or more in the precursor) but applies it at a different stage (precursor formation rather than post-synthesis). This parameter change in timing and concentration allows the system to achieve both excessive doping (for structural stability) and large particle size (15 μm or more), resolving the contradiction between the two requirements.
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 approach enables the production of large particle-sized lithium cobalt oxide with enhanced structural stability and increased battery capacity, energy density, and improved life characteristics, even at high voltages, by uniformly doping the precursor particles.
Implementation Method 1
A positive electrode active material precursor with primary particles of Co3O4 or CoOOH, doped with 3,000 ppm or more of elements like aluminum, achieving an average particle diameter of 15 μm or more, is prepared through a co-precipitation reaction
Data Source
AI summary
The present invention provides a positive electrode active material precursor for a secondary battery which includes primary particles of Co3O4 or CoOOH, wherein the primary particle contains a doping element in an amount of 3,000 ppm or more, and has an average particle diameter (D50) of 15 μm or more, and a positive electrode active material for a secondary battery which includes particles of a lithium cobalt-based oxide, wherein the primary particle contains a doping element in an amount of 2,500 ppm or more, and has an average particle diameter (D50) of 15 μm or more.