Doped Co3O4 Precursor for Bulk-Doped Lithium Cobalt Oxide Cathodes
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Solution Overview
Problem
Lithium cobalt oxide cathode materials in lithium ion batteries undergo irreversible phase changes and structural collapse at high charging voltages, leading to reduced cycle stability and safety performance due to the difficulty in achieving bulk doping of doping elements, which concentrate on the surface rather than diffusing into the bulk phase.
Innovation Solution
The process is advanced by doping metal elements into Co3O4 precursors to form doped Co3-xMxO4, allowing for bulk phase doping of lithium cobalt oxide cathode materials, enhancing structural stability and performance under high-voltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping elements are added to lithium cobalt oxide cathode materials, then structural stability under high-voltage conditions is improved, but doping elements concentrate on the surface rather than diffusing into the bulk phase
Solution Approach 1:
The patent applies preliminary action by doping metal elements into the Co3O4 precursor before the formation of lithium cobalt oxide cathode material. This allows the doping elements to be incorporated into the bulk phase structure during precursor synthesis, ensuring uniform distribution throughout the material rather than concentrating on the surface during subsequent processing.
Solution Approach 2:
The patent utilizes parameter changes by modifying the precursor composition (Co3-xMxO4) before cathode material formation. By adjusting the doping concentration and metal element selection in the precursor stage, the patent achieves controlled diffusion of doping elements into the bulk phase, transforming the distribution pattern from surface-concentrated to uniformly dispersed.
2Use of energy by moving object
If high charging voltage is applied to increase discharge capacity, then energy density is improved, but irreversible phase changes and structural collapse occur
Solution Approach 1:
The patent applies local quality by introducing metal element dopants (such as Al, Ga, Hf, Mg, Sn, Zn, or Zr) at specific lattice positions within the lithium cobalt oxide structure. These localized doping sites create regions of enhanced structural stability that prevent phase transitions and structural collapse during high-voltage charging and discharging cycles, thereby maintaining cycle stability while enabling high discharge capacity.
3Ease of manufacture
If conventional doping methods are used, then surface doping is achieved, but bulk phase doping is difficult to accomplish
Solution Approach 1:
The patent employs preliminary action by performing the doping process during the synthesis of the Co3O4 precursor material, before the lithium cobalt oxide cathode structure is formed. This timing allows doping elements to be incorporated into the bulk phase during precursor formation, making bulk phase doping achievable through a straightforward synthesis process rather than requiring complex post-processing techniques.
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 improves the cycle stability, high-temperature performance, and safety of lithium ion batteries by ensuring that the doping elements are evenly distributed within the bulk phase, preventing structural distortion and maintaining electrochemical performance.
Implementation Method 1
doping elements are difficult to diffuse into a bulk phase of the cobalt source
Implementation Method 2
Mn and Fe-doped Co 3 O 4 nanoparticles were prepared by a simple precipitation method
Data Source
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AI summary
This application relates to a metal oxide and a method for preparing the same. Specifically, Co3O4 is selected as a precursor of lithium cobalt oxide, and one or more metal elements M are doped in the particles of Co3O4 to obtain a doped lithium cobalt oxide precursor Cο3-xMxO4, where 0<x≤0.3. The difference value, measured by a spectrometer of a scanning electron microscope, of the weight percentage of one of M in two identical area regions is E, wherein 0<E≤1% (wt.%). A lithium ion battery with lithium cobalt oxide prepared from the precursor as a cathode material shows great cycle stability, high-temperature energy storage performance and safety performance in a high-voltage (equal to or greater than 4.45 V) charging and discharging environment.