Ni-Rich Cathode Materials With Mg Doping to Prevent Particle Cracks
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Solution Overview
Problem
Existing cathode active materials for lithium ion secondary batteries often exhibit cracks in the particles, which can impair charge/discharge and cycling behavior.
Innovation Solution
A process to produce particulate cathode active materials with the formula (Li1-zM1z)1+x(Ni1-yM2y)1-xO2, involving steps such as providing an Mg-doped oxide or (oxy)hydroxide of Ni, converting it with Na2O2 or NaOH, reacting with LiNO3 or a mixture of LiCl and LiNO3, and removing nitrate and chloride using water or alcohols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a process starting from making a sodium-equivalent and replacing Na+ by Li+ in molten lithium salt is used, then cathode active materials can be produced, but cracks form in the particles which impair charge/discharge and cycling behavior
Solution Approach 1:
The patent applies preliminary action by forming a protective magnesium-doped layer on the nickel oxide/hydroxide surface before the lithium ion exchange process. This pre-treatment step (doping with Mg in step (a)) prevents crack formation during subsequent processing, eliminating the reliability issue while maintaining ease of manufacture through the established multi-step process
2Quantity of substance
If Ni-rich electrode active materials are used to increase capacity, then energy storage capability is improved, but particle cracks develop that deteriorate cycling stability
Solution Approach 1:
The patent applies local quality by introducing magnesium doping at specific locations (surface and grain boundaries) of the Ni-rich particle structure. This localized modification (z = 0.005 to 0.10) provides structural reinforcement exactly where cracks tend to form, allowing high nickel content (95 mol-% or more) to be maintained while improving cycling stability through targeted structural enhancement
3Reliability
If Mg-doped nickel oxide or (oxy)hydroxide is processed through multiple chemical conversion steps, then crack-free cathode material is produced, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing specific process parameters: controlling Mg doping concentration (z = 0.005 to 0.10), precise temperature control during lithium ion exchange (250-350°C), and controlled atmosphere conditions. These parameter optimizations ensure crack-free material formation while keeping the process complexity manageable through well-defined, controllable parameters rather than fundamentally complex procedures
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 resulting cathode active materials have a structure without cracks, demonstrating improved charge/discharge and cycling behavior, and exhibit excellent cycling stability with low capacity fade.
Implementation Method 1
converting said oxide or (oxy)hydroxide provided in step (a) with Na2O2 or Na2O or NaOH to (Na1-zM1z)1+x(Ni1-yM2y)1-xO2
Implementation Method 2
reacting said (Na1-zM1z)1+x(Ni1-yM2y)1-xO2 with LiNO3 or with a mixture of LiCl and LiNO3 at a temperature in the range of from 250 to 350° C.
Implementation Method 3
removing nitrate and, if applicable, chloride from the nitrate containing material from step (c) with water or C1-C3-alkanol
Data Source
AI summary
Disclosed herein is a process for making a particulate compound according to the general formula (Li1-zM1z)1+x(Ni1-yM2y)1-xO2. The process comprising includes the steps of:(a) providing an Mg-doped oxide or (oxy)hydroxide of Ni or composite (oxy)hydroxide of Ni and at least one of Co, Al, Mn, Ti, Zr, Nb, Ta, Mo, or W,(b) converting said the oxide or (oxy)hydroxide provided in step (a) with Na2O2 or Na2O or NaOH to (Na1-zM1z)1+x(Ni1-yM2y)1-xO2,(c) reacting said the (Na1-zM1z)1+x(Ni1-yM2y)1-xO2 with LiNO3 or with a mixture of LiCl and LiNO3 thermally at a temperature in the range of from 250 to 350° C., thereby obtaining a nitrate containing material, and(d) removing nitrate and, if applicable, chloride from the nitrate containing material from step (c) with water or C1-C3-alkanol.