Positive Electrode Precursor Growth for Uniform Sintering
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Solution Overview
Problem
The existing methods for preparing positive electrode active materials for lithium secondary batteries face challenges in achieving uniform sintering and high productivity due to variations in particle size and surface density, leading to reduced reactivity with lithium and penetration of doping elements.
Innovation Solution
A method involving a seed forming step followed by a particle growing step with continuously increasing feed rates of transition metal and ammonium cationic complexing agents, reducing surface density and increasing specific surface area of precursor particles, thereby enhancing reactivity with lithium during sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a batch reactor is used to prepare precursor with constant feed rate, then particle size uniformity is improved, but surface density increases and reactivity with lithium decreases
Solution Approach 1:
The patent applies dynamics by changing the feed rate from constant to continuously increasing during the particle growing step. This dynamic adjustment allows the system to maintain particle size uniformity while preventing excessive surface density increase, thereby preserving reactivity with lithium during sintering.
Solution Approach 2:
The patent changes the parameter of feed rate from constant to continuously increasing. This parameter change directly addresses the contradiction by controlling the growth kinetics to achieve optimal balance between particle size uniformity and surface density, ensuring both manufacturing precision and chemical reactivity.
2Manufacturing precision
If batch reactor is used with constant feed rate, then particle size uniformity is improved, but productivity is reduced
Solution Approach 1:
The patent uses dynamics by implementing a continuously increasing feed rate in the batch reactor. This allows the reaction to proceed efficiently with higher material input rates as particles grow, significantly improving productivity while maintaining particle size uniformity through controlled growth kinetics.
Solution Approach 2:
The patent applies continuity of useful action by continuously increasing the feed rate throughout the particle growing step. This ensures that the reaction proceeds at optimally increasing rates without interruption, maximizing productivity while the continuous adjustment maintains particle size uniformity.
3Productivity
If CSTR is used for continuous co-precipitation, then productivity is improved, but particle size uniformity deteriorates
Solution Approach 1:
The patent applies inversion by using a batch reactor instead of a continuous stirred tank reactor (CSTR). This reverse approach allows precise control over the reaction timeline and feed rate profile, achieving particle size uniformity that is difficult to obtain in continuous systems, while still maintaining high productivity through optimized batch processing.
Solution Approach 2:
The patent changes the operational mode from continuous (CSTR) to batch with dynamically changing parameters. By implementing a continuously increasing feed rate in a batch system, the patent achieves both high productivity and excellent particle size uniformity, resolving the contradiction inherent in continuous processing.
4Stability of the object's composition
If surface density of precursor particles is high, then particle growth is reduced, but reactivity with lithium and penetration of doping elements is suppressed
Solution Approach 1:
The patent applies dynamics by implementing a continuously increasing feed rate that controls particle growth kinetics. This dynamic approach prevents excessive surface density accumulation by adjusting material input in real-time, ensuring particles maintain adequate reactivity with lithium and allow proper penetration of doping elements during sintering.
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 results in improved sintering uniformity, increased reversible capacity, and enhanced productivity of the positive electrode active material, while preventing cracks during the sintering process.
Implementation Method 1
performing a co-precipitation reaction while supplying a transition metal aqueous solution, an ammonium cationic complexing agent, and a basic compound to the reaction solution
Data Source
AI summary
A precursor for a positive electrode active material and a method of making the same are disclosed herein. In some embodiments a method includes forming precursor seeds for a positive electrode active material by a co-precipitation reaction while supplying a transition metal aqueous solution, an ammonium cationic complexing agent, and a basic compound to a reaction solution, and growing precursor particles for a positive electrode active material by a co-precipitation reaction while supplying a transition metal aqueous solution, an ammonium cationic complexing agent, and a basic compound to the reaction solution containing the precursor seeds, wherein the co-precipitation reaction to grow the precursor particles proceeds while continuously increasing feed rates of the transition metal aqueous solution and the ammonium cationic complexing agent.