Bimodal Positive Electrode Precursor Synthesis via Single-Reactor pH Control
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Solution Overview
Problem
The existing methods for preparing positive electrode active materials for lithium secondary batteries are costly and time-consuming, particularly due to the need for separate preparation and mixing of small and large-sized particles, which results in unsatisfactory firing uniformity and increased costs.
Innovation Solution
A method for preparing a bimodal positive electrode active material precursor using a single reactor, involving the preparation of two aqueous transition metal solutions with different compositions and pH-controlled precipitation reactions to produce particles with varying average diameters, allowing for joint firing and doping with elements like Zr, B, and W to enhance firing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate preparation and mixing of small and large-sized particles is performed, then particle size distribution is improved, but preparation costs and preparation time increase
Solution Approach 1:
The patent combines the preparation of small and large-sized particles into a single simultaneous precipitation process using one reactor, eliminating the need for separate preparation and mixing steps. This merging of operations reduces preparation time while maintaining the bimodal particle size distribution through controlled nucleation and growth phases.
Solution Approach 2:
The patent performs preliminary action by controlling the precipitation process in two distinct phases: first inducing nucleation to form small particles, then promoting growth to form large particles. This preliminary control of particle formation mechanisms within a single process enables simultaneous production of bimodal distribution without separate preparation steps.
2Manufacturing precision
If separate preparation and mixing of small and large-sized particles is performed, then particle size distribution is improved, but device complexity increases
Solution Approach 1:
The patent merges the particle size distribution control function into the precipitation process itself, eliminating the need for separate separation devices. By controlling nucleation and growth in a single reactor, the system produces bimodal distribution directly without requiring additional equipment for separation and mixing.
Solution Approach 2:
The patent extracts the particle size control mechanism from the downstream separation and mixing operations and integrates it into the precipitation process. This extraction eliminates the need for separate separation devices by embedding the size distribution control within the formation process itself.
3Manufacturing precision
If separate preparation and mixing of small and large-sized particles is performed, then particle size distribution is improved, but preparation costs increase
Solution Approach 1:
The patent combines multiple operations (nucleation, growth, and size distribution control) into a single precipitation process, eliminating the need for separate preparation and mixing steps. This consolidation reduces equipment requirements, operational complexity, and preparation costs while achieving the desired bimodal particle size distribution.
Solution Approach 2:
The precipitation reactor performs multiple functions simultaneously: it controls nucleation, promotes growth, and achieves size distribution control in one operation. This multi-functionality eliminates the need for separate dedicated equipment for each step, reducing overall preparation costs.
4Manufacturing precision
If different firing temperatures are used for small and large particles, then particle-specific treatment is improved, but firing uniformity deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the precursor particles during precipitation, incorporating different amounts of doping elements into small and large particles. This compositional differentiation allows the particles to have different thermal behaviors that compensate for size-related firing differences, achieving uniform final product properties from a single firing process.
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 reduces preparation costs and time, achieves improved firing uniformity, and simplifies the process by allowing for the simultaneous synthesis of particles with different diameters, resulting in a positive electrode active material with enhanced capacity and stability.
Implementation Method 1
performing a precipitation reaction at pH 12 or more to induce the nucleation of a first positive electrode active material precursor particle, and performing a precipitation reaction at less than pH 12 to induce the growth of the first positive electrode active material precursor particle
Implementation Method 2
performing a precipitation reaction at pH 12 or more to induce the nucleation of a first positive electrode active material precursor particle
Data Source
AI summary
A method of preparing a bimodal positive electrode active material precursor and a positive electrode active material prepared from the same are disclosed herein. In some embodiments, the method includes inputting a first reaction source material including a first aqueous transition metal solution into a reactor, precipitating at pH 12 or more to induce nucleation of a first positive electrode active material precursor particle, and at less than pH 12 to induce growth of the same, inputting a second reaction source material including a second aqueous transition metal solution into the reactor containing the first positive electrode active material precursor particle, precipitating at pH 12 or more to induce the nucleation of a second positive electrode active material precursor particle, and at less than pH 12 to induce simultaneous growth of the first and second positive electrode active material precursor particles, thereby preparing a bimodal positive electrode active material precursor.