Surface-Enriched Nickel Cathode Particles for Longer Li-Ion Cycle Life
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Solution Overview
Problem
Lithium-ion batteries using lithiated nickel-cobalt-manganese oxide (NCM) or lithiated nickel-cobalt-aluminum oxide (NCA) materials face challenges such as poor cycle life, pronounced gassing, and increased internal resistance, limiting their commercial application.
Innovation Solution
Development of particulate materials with a composition Li1+xTM1−xO2, where x is between -0.02 to +0.05, comprising at least 94 mol-% nickel and up to 6 mol-% of metals like Co, Mn, Cu, Mg, Fe, etc., enriched at the surface, and having a particle diameter of 2 to 20 μm, which are agglomerates of spherical primary particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel content materials (LiNiO2) are used to improve capacity and energy density, then energy density is improved, but cycle life deteriorates and internal resistance increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the interior maintains high nickel content (≥94 mol-%) for high energy density, while the outer surface is enriched with stabilizing metals (Co, Mn, Al, etc.) to improve cycle life. This spatial differentiation of composition allows simultaneous optimization of both energy density and reliability.
Solution Approach 2:
The patent creates a composite material structure combining nickel-rich core regions with metal-enriched surface regions. The core provides high capacity while the surface composite layer provides structural stability during cycling, resolving the contradiction between energy density and cycle life.
2Quantity of substance
If high nickel content materials are used to improve capacity, then capacity is improved, but gassing increases
Solution Approach 1:
The surface enrichment with stabilizing metals creates a protective layer that locally suppresses gassing reactions at the electrode-electrolyte interface, while the high-nickel core maintains high capacity. This local quality differentiation resolves the contradiction between capacity and gassing.
3Quantity of substance
If high nickel content materials are used to improve capacity, then capacity is improved, but internal resistance increases
Solution Approach 1:
The metal-enriched surface layer acts as a protective barrier that reduces side reactions and maintains lower internal resistance, while the nickel-rich core provides high capacity. This spatial composition gradient resolves the contradiction between capacity and internal resistance.
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 materials exhibit superior cycling stability and reduced resistance growth, combining high energy density and improved cycling stability, making them suitable for lithium-ion batteries.
Implementation Method 1
wherein said metals M1 are enriched at the outer surface of the secondary particles of said particulate material
Implementation Method 2
The calcination—or firing—generally also referred to as thermal treatment or heat treatment of the precursor—is usually carried out at temperatures in the range of from 600 to 1,000° C. During the thermal treatment a solid-state reaction takes place
Implementation Method 3
During the thermal treatment a solid-state reaction takes place, and the electrode active material is formed
Data Source
AI summary
Particulate materials of the composition Li1+xTM1−xO2 wherein x is in the range of from −0.02 to +0.05, TM comprises at least 94 mol-% nickel and up to 6 mol-% of at least three metals M1 selected from Co, Mn, Cu, Mg, Fe, B, Al, Ce, Sn, Zr, Zn, Nb, Ta, Y, Mo and W, wherein said metals M1 are enriched at the outer surface of the secondary particles of said particulate material, and wherein said particulate material has an average particle diameter (D50) in the range of from 2 to 20 μm.