Lithium-Nickel Composite Oxide Purification by Magnetic Fe/Cr Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-nickel composite oxides used as positive electrode materials in lithium-ion secondary batteries suffer from inferior cycle characteristics and impaired battery performance in high-temperature environments due to high Fe and Cr content, affecting thermal stability.
Innovation Solution
A method involving magnetic attraction using rod-shaped magnets to reduce Fe and Cr content in lithium-nickel composite oxide slurry, with specific magnet placement and surface area per unit volume configurations to effectively attract and retain these metals, resulting in a content of less than 10 ppb.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium-nickel composite oxide is synthesized with high Fe and Cr content, then manufacturing cost is reduced, but thermal stability and cycle characteristics deteriorate
Solution Approach 1:
The patent applies magnetic separation to extract and remove Fe and Cr impurities from the lithium-nickel composite oxide slurry. By passing the slurry through a magnetic field, magnetic Fe and Cr particles are separated from the non-magnetic lithium-nickel composite oxide, reducing their content to below 10 ppb and improving thermal stability while maintaining cost-effectiveness
Solution Approach 2:
The patent changes the magnetic field parameters by using rod-shaped magnets with specific dimensions (length 50-200 mm, diameter 10-50 mm) and arranging them at specific intervals (10-50 mm) in the purification device. This optimization of magnetic field strength and distribution enables effective removal of Fe and Cr impurities
2Device complexity
If lithium-nickel composite oxide is synthesized with high Fe and Cr content, then production process is simplified, but cycle characteristics deteriorate
Solution Approach 1:
The patent introduces a magnetic separation step to extract Fe and Cr impurities from the slurry. This relatively simple magnetic purification process, using rod-shaped magnets arranged in a column, effectively removes impurities without significantly complicating the overall production flow, thereby improving cycle characteristics
Solution Approach 2:
The patent uses water as an intermediary medium to create a slurry that enables magnetic separation. The slurry form allows Fe and Cr impurities to be suspended and effectively separated by magnetic fields, facilitating impurity removal while maintaining process simplicity
3Manufacturing precision
If rod-shaped magnets are placed closer together, then Fe and Cr removal efficiency is improved, but device complexity increases
Solution Approach 1:
The patent optimizes the spacing parameter between rod-shaped magnets to 10-50 mm, and sets magnet dimensions (length 50-200 mm, diameter 10-50 mm) to achieve effective Fe and Cr removal. This parameter optimization balances removal efficiency with device simplicity, avoiding overly complex arrangements
4Reliability
If magnetic purification is applied, then thermal stability is improved, but processing time is increased
Solution Approach 1:
The patent replaces complex chemical purification methods with a simpler magnetic field-based separation process. This mechanical/physical approach using rod-shaped magnets in a column enables rapid removal of Fe and Cr impurities without lengthy chemical treatment steps, minimizing processing time addition
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 significantly improves the thermal stability of lithium-ion secondary batteries by reducing Fe and Cr content, enhancing their performance and stability, particularly in high-temperature conditions.
Implementation Method 1
magnetic attraction using rod-shaped magnets to reduce Fe and Cr content in lithium-nickel composite oxide slurry
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a lithium-nickel composite oxide, wherein the lithium-nickel composite oxide is represented by a following general formula: Li1+uNixCoyAsBtO2+α, wherein u, x, y, s, t and α in the formula satisfy 0≦u0.3, 0.03≦x≦0.93, 0.03≦y≦0.50, 0.04 ≦s≦0.6, 0≦t<0.1, 0≦α<0.3 and x+y+s+t=1, wherein an element A is at least one selected from Mn and Al, and an element B is at least one selected from Mg, Ca, Ti, V, Zr, Nb, Mo, Sr and W, and wherein a content of Fe is less than 10 ppb, and a content of Cr is less than 10 ppb.