Gradient Aluminum NCA Precursor via Co-precipitation
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Solution Overview
Problem
Current methods for preparing nickel-cobalt-aluminum cathode materials for lithium ion batteries face challenges such as thermodynamic instability, hygroscopicity, and difficulty in forming a homogeneous structure, leading to issues like capacity attenuation, poor rate performance, and storage performance.
Innovation Solution
A method involving co-precipitation to produce a spherical nickel-cobalt-aluminum hydroxide precursor with a gradient distribution of aluminum, where a complexing solution containing aluminum is gradually added to a mixed solution of nickel and cobalt salts, allowing for continuous increase in aluminum concentration from the core to the surface of the precursor, enhancing stability and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If NCA material is prepared under pure oxygen atmosphere to oxidize divalent nickel to trivalent nickel, then trivalent nickel content increases, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the chemical parameters of the precursor solution by controlling the pH value and aluminum salt addition during co-precipitation. By adjusting these parameters, the method enables in-situ formation of trivalent nickel species in the precursor, eliminating the need for subsequent pure oxygen atmosphere treatment during calcination.
2Reliability
If NCA material is manufactured in low humidity environment to prevent hydrolysis reactions, then material stability is improved, but production cost and process complexity increase
Solution Approach 1:
The patent performs preliminary action by pre-forming a stable gradient structure during the co-precipitation process. The gradient aluminum distribution and controlled pH conditions create a precursor structure that is inherently resistant to hydrolysis, allowing subsequent processing to occur in normal humidity environments without compromising material stability.
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 method results in a cathode material with improved electrochemical performance, stability, and processability, reducing sensitivity to humidity and temperature, and achieving high energy density and safety stability.
Implementation Method 1
A method involving co-precipitation to produce a spherical nickel-cobalt-aluminum hydroxide precursor with a gradient distribution of aluminum
Data Source
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AI summary
Provided are methods for preparing a nickel-cobalt-aluminum precursor material and a cathode material with a gradient distribution of aluminum element. The precursor material and the cathode material based on the precursor material prepared by the methods are of sphere or sphere-like shapes in which the distribution of the aluminum element is changed in a gradient manner, and the particle size distribution is uniform. The synthesized material has a high tap density, is not sensitive to ambient carbon dioxide and moisture, and has a good processability, a high specific capacity and a good stability property.