Li-Ni Composite Oxide Core-Shell Particles for Battery Thermal Stability
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Solution Overview
Problem
Lithium nickel oxide (LiNiO2) batteries suffer from poor thermal stability and cycle characteristics due to crystal structure instability during charge/discharge reactions, leading to reduced performance in non-aqueous electrolyte secondary batteries.
Innovation Solution
The development of Li-Ni composite oxide particles with a specific composition, where a Li-Ni-Co-Mn composite oxide is coated onto the surface of core particles, enhancing thermal stability and maintaining high capacity through a wet chemical or dry mechanical treatment, followed by thermal treatment in an oxygen atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LiNiO2 is used as a positive electrode active material to achieve large charge/discharge capacity, then the battery exhibits high energy density, but the crystal structure suffers from Jahn-Teller distortion and thermal stability deteriorates under charged condition
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core maintains high Ni content (LiNi0.8Co0.1Mn0.1O2) for high capacity while the outer shell has modified composition (LiNi0.8Co0.1Mn0.1O2 with different stoichiometry or coating) for structural stability. This spatial differentiation of material properties resolves the contradiction between high capacity and thermal stability.
Solution Approach 2:
The patent uses composite materials by combining LiNi0.8Co0.1Mn0.1O2 core particles with an outer layer of modified lithium nickel oxide or coating materials. This composite structure allows the inner core to provide high capacity while the outer layer provides structural stability and resistance to Jahn-Teller distortion, simultaneously achieving both high energy density and thermal stability.
2Productivity
If LiNiO2 undergoes charge/discharge reactions to release lithium ions, then electrochemical activity is enhanced, but crystal structure instability increases leading to poor cycle characteristics
Solution Approach 1:
The patent applies preliminary action by pre-modifying the crystal structure through controlled synthesis conditions (stoichiometry adjustment, doping with Co and Mn) before the charge/discharge cycles begin. This pre-treatment creates a more stable crystal framework that can accommodate lithium ion extraction/insertion without undergoing Jahn-Teller distortion, thus maintaining both high electrochemical activity and structural stability during cycling.
Solution Approach 2:
The patent changes material parameters by adjusting the stoichiometric ratios of Li, Ni, Co, and Mn in the composite oxide, and controlling particle morphology and size distribution. These parameter modifications optimize the balance between electrochemical activity (through adequate Ni content) and crystal structure stability (through Co and Mn doping and stoichiometry control), enabling good cycle characteristics.
3Manufacturing precision
If Ni composite hydroxide particles are used to produce Li-Ni composite oxide with high packing property, then manufacturing precision is improved, but the process requires strict control of properties, crystallinity and impurities which increases device complexity
Solution Approach 1:
The patent changes processing parameters by optimizing the calcination temperature range (900-1000°C), controlling the stoichiometry of starting materials, and adjusting particle size distribution of Ni composite hydroxide. These parameter optimizations achieve high packing density and consistent product quality while providing clear, controllable process specifications that reduce manufacturing complexity.
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 coated Li-Ni composite oxide particles exhibit improved thermal stability and safety under charged conditions while maintaining a high discharge capacity, suitable for use as a positive electrode active material in non-aqueous electrolyte secondary batteries.
Implementation Method 1
thermal treatment in an oxygen atmosphere
Implementation Method 2
thermal treatment in an oxygen atmosphere
Implementation Method 3
exhibit improved thermal stability and safety under charged conditions
Data Source
Figure 1~2
Figure 3
AI summary
The present invention relates to Li-Ni composite oxide particles for a non-aqueous electrolyte secondary battery which have a large charge/discharge capacity and are excellent in thermal stability under a charged condition. The above object can be achieved by the Li-Ni composite oxide particles for a non-aqueous electrolyte secondary battery, comprising a Li-Ni composite oxide whose secondary particles form core particles thereof and have a composition represented by the formula: Lix1Ni1-y1-z1-w1Coy1Mnz1Mw1O2 (in which 0.9 ≤ x1 ≤ 1.3; 0.1 ≤ y1 ≤ 0.3; 0.0 ≤ z1 ≤ 0.3; 0 ≤ w1 s 0.1; and M is at least one metal selected from the group consisting of Al and Fe), wherein a Li-Ni composite oxide having a composition represented by the formula: Lix2Ni1-y2-z2-w2Coy2Mnz2Mw2O2 (in which 0.9 ≤ x2 ≤ 1 + z2; 0 ≤ y2 ≤ 0.33; 0 ≤ z2 ≤ 0.5; 0 ≤ w2 ≤ 0.1; and M is at least one metal selected from the group consisting of Al, Fe, Mg, Zr and Ti, is coated or present on a surface of the respective secondary particles.