Single-Crystal NCM Cathode Calcination Without Flux Washing
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Solution Overview
Problem
Existing processes for producing single crystalline cathode active materials (SCM) face challenges in achieving well-shaped morphology suitable for industrial scale production, requiring additional washing steps to remove flux agents like Na2SO4 and NaCl, which complicates the process and increases costs.
Innovation Solution
A multi-step calcination process involving a transient thermal treatment (TTT) is applied to a mixture of nickel, cobalt, and manganese precursors with lithium, optimizing conditions to produce single crystalline NCM with octahedral shapes, enhancing pressed density and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If flux agents like Na2SO4 and NaCl are added during calcination to form well-shaped single crystal cathode active materials, then the morphology and crystal structure are improved, but additional washing steps are required to remove residual flux agents, which complicates the process and increases costs
Solution Approach 1:
The patent removes the harmful flux agents (Na2SO4 and NaCl) from the calcination process entirely. Instead of using these external additives, the invention employs a self-organizing mechanism where the precursor particles themselves serve as templates for single crystal formation, eliminating the need for washing steps and reducing process complexity while maintaining morphology quality
Solution Approach 2:
The precursor particles autonomously organize into single crystal structures during calcination without requiring external flux agents. The controlled thermal treatment enables the material to self-structure into well-defined morphologies, making the system self-sufficient and eliminating the need for additional purification steps
2Shape
If flux agents are used during calcination to produce well-shaped single crystal cathode active materials, then the crystal structure quality is improved, but the production cost increases due to additional washing steps
Solution Approach 1:
The invention extracts and eliminates the need for expensive flux agents and associated washing operations. By using a direct calcination approach with controlled atmospheric conditions, the process achieves high-quality single crystal formation without additional material costs or processing steps, thereby reducing manufacturing costs
Solution Approach 2:
The patent replaces expensive flux agents with a simple, cost-effective atmospheric control approach during calcination. The use of controlled atmosphere (oxygen or air) as a temporary processing condition enables single crystal formation without requiring costly chemical additives that would need to be removed
3Stability of the object's composition
If conventional single crystal cathode active materials are produced, then the material achieves single crystal structure, but the particle morphology is irregular and shapeless, which does not meet the definition of well-shaped single crystals
Solution Approach 1:
The patent applies different local conditions during calcination: the external atmosphere is controlled to enable surface organization and morphology development, while the internal crystal structure develops through self-organization. This local differentiation allows simultaneous achievement of single crystal structure and well-defined particle morphology
Solution Approach 2:
The invention changes the calcination parameters, specifically using controlled atmosphere (oxygen or air) at specific temperature ranges and durations. These parameter modifications enable the material to develop both single crystal structure and regular polyhedral morphology, transforming the outcome from irregular to well-shaped
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 process results in single crystalline NCM with improved pressed density and electron conductivity, facilitating higher energy density and faster electron transportation, while simplifying the production process for industrial scalability.
Implementation Method 1
calcining the mixture obtained from step ii), wherein said step iii) comprises multi-step calcination
Implementation Method 2
A multi-step calcination process involving a transient thermal treatment (TTT) is applied
Implementation Method 3
calcining the mixture obtained from step ii), wherein said step iii) comprises multi-step calcination
Data Source
AI summary
Disclosed herein a process for preparing a cathode active material of Formula (I) LiNixCoyMnzO2, including steps of: i) preparing a precursor of hydroxides or carbonates of Ni, Co and Mn; ii) mixing the precursor obtained from step i) with a source of Li; and iii) calcining the mixture obtained from step ii), where step iii) includes multi-step calcination, where x is in a range of from 0.80 to 0.95 and preferably from 0.80 to 0.92, y is in a range of from 0.01 to 0.15 and preferably from 0.01 to 0.12, and z is in a range of from 0.01 to 0.15 and preferably from 0.01 to 0.12, and the sum of x, y and z is 1.