High-Nickel Cathode Material Doping for Structural Stability
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Solution Overview
Problem
Conventional lithium nickel-cobalt-manganese-based composite oxides with high nickel content suffer from structural instability, cation mixing, and increased lithium impurities, leading to reduced capacity, resistance, and lifespan in lithium secondary batteries.
Innovation Solution
A positive electrode active material comprising a lithium nickel-cobalt-manganese-based composite oxide with a nickel content of 90 mol% or more, doped with Al, Zr, and/or Ti, specifically with Al at 8,000 ppm or more, and a total doping content of 9,000 to 12,000 ppm, is prepared by mixing precursors and calcining at 650°C to 850°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content (90 mol% or more) is used in lithium nickel-cobalt-manganese-based composite oxide, then capacity is improved, but structural stability deteriorates due to cation mixing and oxygen desorption
Solution Approach 1:
The patent applies local quality by doping metal elements (Al, Zr, Ti) at specific locations within the composite oxide structure. The doping elements are introduced at controlled concentrations (Al: 8,000-12,000 ppm, Zr: 1,000-5,000 ppm, Ti: 1,000-5,000 ppm) to locally stabilize the crystal structure at critical sites, preventing cation mixing and oxygen desorption while maintaining high overall nickel content (90 mol% or more).
Solution Approach 2:
The patent creates a composite material system by combining lithium nickel-cobalt-manganese-based composite oxide with multiple doping elements (Al, Zr, Ti). This composite approach leverages the synergistic effects of different elements: Al provides structural stabilization, Zr enhances oxygen resistance, and Ti improves lattice stability, collectively enabling high nickel content while maintaining structural integrity.
2Quantity of substance
If high nickel content is used, then reversible capacity is improved, but gas generation increases during charge and discharge processes
Solution Approach 1:
The patent converts the potentially harmful high reactivity of nickel (which causes gas generation) into a benefit by carefully controlling the nickel content at 90 mol% or more while simultaneously introducing doping elements that suppress unwanted side reactions. The doping elements act as guardians that allow the high nickel content to provide capacity while preventing gas-generating reactions.
3Stability of the object's composition
If conventional doping methods are used, then structural stability is improved, but capacity characteristics remain insufficient
Solution Approach 1:
The patent achieves superior performance by optimizing multiple parameters simultaneously: nickel content (90 mol% or more), doping element types (Al, Zr, Ti), doping concentrations (Al: 8,000-12,000 ppm, Zr: 1,000-5,000 ppm, Ti: 1,000-5,000 ppm), and calcination temperature (650-850°C). This multi-parameter optimization enables both high capacity and structural stability, overcoming the limitations of conventional single-parameter doping approaches.
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 doped composite oxide enhances structural stability, reduces resistance, and improves capacity and lifespan by mitigating volume changes and cation mixing, while minimizing cobalt content for cost-effectiveness.
Implementation Method 1
a metal element M1 doped in the lithium nickel-cobalt-manganese-based composite oxide, wherein the metal element M1 comprises two or more selected from the group consisting of Al, Zr and Ti
Implementation Method 2
calcining at 650°C to 850°C
Data Source
Figure 1
AI summary
The present invention relates to a positive electrode active material comprising: a lithium nickel-cobalt-manganese-based composite oxide having a nickel content 90 mol% or more among metals excluding lithium; and a metal element M1 doped in the lithium nickel-cobalt-manganese-based composite oxide, wherein the metal element M1 comprises two or more selected from the group consisting of Al, Zr and Ti, and certainly comprises Al, a weight of Al is 8,000 ppm or more based on a total weight of the positive electrode active material, and a total weight of the metal element M1 is 9,000 ppm to 12,000 ppm based on the total weight of the positive electrode active material, a method for preparing the same, and a positive electrode and a lithium secondary battery comprising the positive electrode active material.