Tungsten-Layered Metal Composite Hydroxide for Low-Resistance Cathodes
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Solution Overview
Problem
Existing methods for producing positive electrode active materials for lithium-ion batteries face issues such as non-uniform tungsten distribution leading to increased reaction resistance, non-uniform particle sizes, and decreased cycle characteristics, making them unsuitable for high-output applications.
Innovation Solution
A two-stage crystallization process is employed to produce a metal composite hydroxide with a tungsten-concentrated layer, involving a first crystallization process for nuclear generation and particle growth, followed by a second process to form a tungsten-concentrated layer, with controlled pH and atmosphere switching to achieve uniform tungsten distribution and a multilayer structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-stage crystallization process is employed to form a tungsten-concentrated layer, then uniform tungsten distribution and reduced reaction resistance are achieved, but the production process complexity increases
Solution Approach 1:
The crystallization process is divided into two distinct stages: a first crystallization process for nuclear generation and particle growth, and a second crystallization process for forming a tungsten-concentrated layer. This segmentation allows each stage to be optimized independently, achieving uniform tungsten distribution while maintaining controllable process complexity.
Solution Approach 2:
The first crystallization process performs preliminary actions of nuclear generation and particle growth before the second crystallization process forms the tungsten-concentrated layer. This preliminary structuring enables subsequent uniform tungsten incorporation and reduces final reaction resistance.
2Manufacturing precision
If atmospheric switching is performed multiple times during crystallization to control particle structure, then desired particle morphology is achieved, but the manufacturing time increases
Solution Approach 1:
The atmosphere is switched periodically between oxidizing and non-oxidizing conditions during the crystallization processes. This periodic atmospheric switching enables precise control of particle morphology and tungsten distribution while managing the total process time through structured cycles.
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 positive electrode active material with reduced reaction resistance, high output, and improved crystallinity, suitable for high-energy density lithium-ion batteries.
Implementation Method 1
a first crystallization process of supplying a first raw material aqueous solution containing nickel and manganese and optionally cobalt and metal element M into a reaction tank, adjusting a pH of the reaction aqueous solution, and performing a crystallization reaction
Implementation Method 2
adjusting a pH of the reaction aqueous solution, and performing a crystallization reaction
Data Source
AI summary
A method for producing a metal composite hydroxide, which includes a first crystallization process of supplying a first raw material aqueous and performing a crystallization reaction and a second crystallization process of supplying a second raw material aqueous solution containing a more amount of tungsten than the first raw material aqueous solution and performing a crystallization reaction to form a tungsten-concentrated layer and in which switching of reaction atmosphere from either atmosphere of a non-oxidizing atmosphere or an oxidizing atmosphere to the other atmosphere is performed two or more times in particle growth and the time for supplying the second raw material aqueous solution into the reaction tank in the non-oxidizing atmosphere is 50% or more with respect to the entire time for supplying the second raw material aqueous solution into the reaction tank.