Cathode Precursor Tap Density via Cobalt Hydroxide Composite
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Solution Overview
Problem
Conventional lithium cobalt oxide cathode active materials for lithium batteries face challenges in achieving stable electrochemical characteristics due to difficulties in controlling cobalt content and particle size, resulting in insufficient energy density.
Innovation Solution
A composite cathode active material precursor is developed, comprising cobalt hydroxide and cobalt oxyhydroxide, which enhances the theoretical density and energy density of lithium batteries by incorporating both materials, with specific XRD peaks and particle characteristics optimizing the cathode's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cobalt oxide is prepared from cobalt hydroxide with theoretical tap density of 4 g/cm³ or higher, then the energy density should be high, but the practically prepared cobalt hydroxide has tap density of 1.5 g/cm³ or lower resulting in insufficient energy density
Solution Approach 1:
The patent applies composite materials by combining cobalt hydroxide and cobalt oxyhydroxide in a layered structure. The cobalt oxyhydroxide layer (with higher theoretical density of 5.9 g/cm³) is formed on the surface of cobalt hydroxide particles, creating a composite structure that achieves practical tap density closer to theoretical values while maintaining stable electrochemical characteristics
Solution Approach 2:
The patent changes physical and chemical parameters by controlling the oxidation process of cobalt hydroxide to form cobalt oxyhydroxide. By adjusting oxidation conditions (temperature, time, atmosphere), the patent optimizes the density and composition of the composite precursor, transforming it from low-density pure cobalt hydroxide to high-density composite material
2Ease of manufacture
If conventional methods are used to prepare lithium cobalt oxide by mixing and heat-treating cobalt oxide with lithium compound, then the production process is simple, but the cobalt content and particle size distribution cannot be controlled resulting in unstable electrochemical characteristics
Solution Approach 1:
The patent applies preliminary action by pre-forming the composite precursor with controlled cobalt content and uniform particle size distribution before the actual lithium cobalt oxide synthesis. The cobalt hydroxide/cobalt oxyhydroxide composite is prepared in advance with precise compositional control, which then serves as the starting material for lithium cobalt oxide production, ensuring consistent electrochemical characteristics
Solution Approach 2:
The patent changes the chemical composition parameters by controlling the ratio of cobalt hydroxide to cobalt oxyhydroxide in the composite precursor. This compositional control enables precise regulation of cobalt content in the final lithium cobalt oxide product, achieving manufacturing precision while maintaining ease of production
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 composite precursor increases the tap density and energy density of lithium batteries, improving output and charging/discharging characteristics while maintaining stable particle sizes and reduced residual lithium content.
Implementation Method 1
mixing a solution including a transition metal source and a solution including a reducing agent to prepare a mixture and obtain a precipitate from the mixture
Implementation Method 2
A cobalt oxide may be prepared from a cobalt hydroxide (Co(OH)2), which is a cobalt precursor
Data Source
AI summary
Provided are a composite precursor of a cathode active material, the composite precursor including a cobalt hydroxide and a cobalt oxyhydroxide, where an X-ray diffraction spectrum of the composite precursor has a first peak observed at a diffraction angle (2θ) of 19.5°±0.5° and a second peak observed at a diffraction angle (2θ) of 38.5°±0.5°; a cathode active material prepared from the composite precursor; a cathode and a lithium battery including the composite precursor; and a method of preparing the composite precursor.