Lithium Cobalt Oxide Preparation via Oxidizing Precipitation
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in achieving high energy density and stable electrochemical performance, particularly in high-temperature applications, due to limitations in cobalt oxide particle density and lithium cobalt oxide preparation methods that often require excess lithium precursors, leading to increased costs and reduced electrode density.
Innovation Solution
A method for preparing cobalt oxide with a high tap density and specific particle size distribution, followed by the formation of lithium cobalt oxide with controlled pellet density and spherical particle shape, using a precipitation reaction under an oxidizing atmosphere without thermal treatment, which allows for stoichiometric lithium precursor usage and reduced residual lithium, resulting in improved electrode density and electrochemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional preparation methods are used for lithium cobalt oxide, then the synthesis process is simpler, but the electrode density decreases and preparation costs increase due to excess lithium precursors
Solution Approach 1:
The invention changes the preparation parameters by conducting the reaction under oxidizing atmosphere and controlling pH and temperature parameters to achieve high electrode density without requiring excess lithium precursors, thus resolving the contradiction between manufacturing precision and ease of manufacture
Solution Approach 2:
The invention uses oxidizing atmosphere (oxygen or air) during the precipitation reaction to oxidize cobalt ions to the desired oxidation state, eliminating the need for subsequent thermal treatment and excess lithium precursors, thereby improving electrode density while maintaining ease of manufacture
2Reliability
If conventional thermal treatment methods are used, then the synthesis is more straightforward, but residual lithium increases and electrochemical stability decreases
Solution Approach 1:
The invention employs oxidizing atmosphere during precipitation to achieve complete oxidation of cobalt ions, eliminating the need for thermal treatment that typically leaves residual lithium, thus improving electrochemical stability while reducing substance loss
Solution Approach 2:
The invention replaces the thermal treatment mechanism with a chemical oxidation mechanism occurring during precipitation, substituting high-temperature processing with controlled chemical reactions at lower temperatures, thereby reducing residual lithium and improving reliability
3Quantity of substance
If high tap density cobalt oxide is used, then the energy density improves, but the particle size control becomes more difficult
Solution Approach 1:
The invention optimizes reaction parameters including pH (11.0-12.0), temperature (60-80°C), and oxidizing atmosphere conditions to simultaneously achieve high tap density cobalt oxide with controlled particle size distribution, resolving the contradiction between quantity of substance and manufacturing precision
Solution Approach 2:
The invention creates local conditions within the reaction system (pH gradients, temperature distribution, oxygen concentration) to control nucleation and growth rates, enabling formation of cobalt oxide particles with high density and uniform size distribution
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 approach results in lithium secondary batteries with enhanced lifetime and rate characteristics, improved capacity retention, and reduced preparation costs, as evidenced by increased pellet density and stable X-ray diffraction spectra, indicating better crystal plane ratios and atomic ratios in the cobalt oxide and lithium cobalt oxide.
Implementation Method 1
performing a precipitation reaction of a mixture including a cobalt precursor and a precipitant, and the precipitation reaction is carried out under an oxidizing gas atmosphere to obtain the cobalt oxide
Implementation Method 2
the precipitation reaction is carried out under an oxidizing gas atmosphere to obtain the cobalt oxide
Data Source
AI summary
A cobalt oxide for a lithium secondary battery, a method of preparing the cobalt oxide; a lithium cobalt oxide for a lithium secondary battery formed from the cobalt oxide; and a lithium secondary battery having a positive electrode including the lithium cobalt oxide, the cobalt oxide having a tap density of about 2.8 g/cc to about 3.0 g/cc, and an intensity ratio of about 0.8 to about 1.2 of a second peak at 2θ of about 31.3±1° to a first peak at 2θ of about 19±1° in X-ray diffraction spectra, as analyzed by X-ray diffraction.