Ni-Rich Cathode Material Synthesis With Mg Doping for Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Ni-rich electrode active materials, such as LiNiO2, face challenges due to difficulties in stoichiometric synthesis and instability issues, particularly in their de-lithiated state, which affect their electrochemical performance and commercial viability.
Innovation Solution
A process involving the steps of providing a hydroxide or oxide of Ni, mixing with lithium and magnesium, followed by thermal treatment, and subsequent mixing with additional metals like Al, Co, Mn, Nb, Ta, Mo, or W, and further thermal processing, to produce a Ni-rich electrode active material with improved electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pure LiNiO2 is synthesized, then high nickel content (75 mol-% or more) is achieved, but stoichiometric control becomes difficult and stability problems occur
Solution Approach 1:
The patent applies local quality by introducing magnesium at specific local positions within the crystal structure - substituting nickel at the transition metal site and occupying lithium sites in controlled amounts (0.01-0.5 mol%). This localized modification at specific crystallographic positions enables precise control of stoichiometry while maintaining high overall nickel content (75 mol-% or more), resolving the contradiction between high nickel content and stoichiometric control precision.
Solution Approach 2:
The patent employs parameter changes by systematically varying the magnesium content parameter (0.01-0.5 mol%) and the ratio parameters (Li/(Ni+Co+Mn) and Mg/(Ni+Co+Mn) both 0.95-1.05) to achieve optimal stoichiometric control. These parameter adjustments transform the difficult-to-control pure LiNiO2 synthesis into a controllable process with defined compositional ranges, directly addressing the manufacturing precision issue while maintaining high nickel content.
2Quantity of substance
If pure LiNiO2 is synthesized, then high nickel content is achieved, but stability problems in de-lithiated state occur
Solution Approach 1:
The patent applies local quality by introducing magnesium at specific local positions within the crystal structure - substituting nickel at the transition metal site and occupying lithium sites in controlled amounts (0.01-0.5 mol%). This localized modification at specific crystallographic positions enables precise control of stoichiometry while maintaining high overall nickel content (75 mol-% or more), resolving the contradiction between high nickel content and stoichiometric control precision.
Solution Approach 2:
The patent employs composite materials by creating a multi-element system (Li-Mg-Ni-Co-Mn-O) that combines the benefits of high-nickel capacity with the stabilizing effects of magnesium and other transition metals. The composite cathode material with controlled composition ranges (Li/(Ni+Co+Mn) = 0.95-1.05, Mg/(Ni+Co+Mn) = 0.95-1.05) achieves both high nickel content and improved stability in the de-lithiated state, directly resolving the reliability issue.
3Reliability
If multi-element composite is used, then stability and electrochemical properties improve, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining optimal composition ranges for all elements (Li/(Ni+Co+Mn) = 0.95-1.05, Mg/(Ni+Co+Mn) = 0.95-1.05, Ni+Co+Mn ≥ 0.75 mol%) before the synthesis process. This preliminary specification of target compositions guides the manufacturing process, reducing complexity by providing clear compositional targets rather than requiring complex real-time process control during synthesis.
Solution Approach 2:
The patent employs parameter changes by systematically varying the magnesium content parameter (0.01-0.5 mol%) and the ratio parameters (Li/(Ni+Co+Mn) and Mg/(Ni+Co+Mn) both 0.95-1.05) to achieve optimal stoichiometric control. These parameter adjustments transform the difficult-to-control pure LiNiO2 synthesis into a controllable process with defined compositional ranges, directly addressing the manufacturing precision issue while maintaining high nickel content.
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 electrode active materials with excellent electrochemical properties, including good capacity retention, addressing the stability and synthesis challenges of traditional Ni-rich materials.
Implementation Method 1
treating the mixture obtained from step (b) thermally at a temperature in the range of from 450 to 650°C, thereby obtaining an intermediate
Implementation Method 2
treating the mixture obtained from step (d) thermally at a temperature in the range of from 500 to 850°C
Data Source
AI summary
The present invention is related to a process for making an electrode active material wherein said process comprises the following steps: (a) Providing a hydroxide TM(OH)2 or at least one oxide TMO or at least one oxyhydroxide of TM or a combination of at least two of the foregoing wherein TM is one or more metals and contains at least 97 mol-% Ni and, optionally, in total up to 3 mol-% of at least one metal selected from Al, Ti, Zr, V, Co, Zn, Ba, and Mn; (b) mixing said hydroxide TM(OH)2 or oxide TMO or oxyhydroxide of TM or combination with a source of lithium and a source of Mg wherein the molar amount of (Li + Mg) cor-responds to 75 to 95 mol-% of TM; (c) treating the mixture obtained from step (b) thermally at a temperature in the range of from 450 to 650°C, thereby obtaining an intermediate; (d) mixing the intermediate from step (c) with a source of Li and with at least one compound of a metal M1 selected from Al, Zr, Co, Mn, Nb, Ta, Mo, and W; (e) treating the mixture obtained from step (d) thermally at a temperature in the range of from 500 to 850°C.