Over-lithiated Layered Oxide Manufacturing for High Tap Density
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Solution Overview
Problem
Over-lithiated layered lithium metal composite oxides face challenges in growing large primary particle diameters, which limits their volumetric energy density as electrode materials, particularly in lithium-ion cells for electric vehicles and hybrid electric vehicles.
Innovation Solution
A production method involving calcining a lithium metal composite oxide with a specific composition and then mixing it with a lithium compound to enhance crystal growth and increase primary particle diameter, thereby improving tap density and charge/discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If over-lithiated layered lithium metal composite oxide is used to increase charge/discharge capacity, then the capacity is improved, but the primary particle diameter cannot be made sufficiently large
Solution Approach 1:
The patent applies preliminary action by first forming a lithium metal composite oxide with controlled composition (where 0 < x < 0.5 in Li1+xM1−xO2) before final over-lithiation. This preliminary structure formation allows subsequent lithium addition to enhance capacity without compromising particle growth, as the base structure is already optimized for crystal development.
Solution Approach 2:
The patent utilizes parameter changes by systematically adjusting the lithium content parameter (x) in the formula Li1+xM1−xO2 and controlling the ratio between different lithium metal composite oxides. By optimizing these compositional parameters, the patent achieves both large primary particle diameter (1 μm to 60 μm) and high charge/discharge capacity simultaneously.
2Quantity of substance
If over-lithiated layered lithium metal composite oxide is used to improve charge/discharge capacity, then the capacity is improved, but the volumetric energy density cannot be sufficiently enhanced
Solution Approach 1:
The patent optimizes volumetric energy density by controlling the particle size parameter (primary particle diameter of 1-60 μm) and composition parameter (lithium content x). This parameter optimization ensures high capacity per volume by achieving adequate particle size for dense packing while maintaining high lithium content for capacity.
Solution Approach 2:
The patent applies preliminary structure formation with controlled composition before final over-lithiation, ensuring that the crystal structure is optimized for density. This preliminary optimization of the base structure (Li1+xM1−xO2 with 0 < x < 0.5) enables subsequent lithium addition to increase capacity without proportionally increasing volume.
3Quantity of substance
If lithium content is increased to achieve over-lithiation, then charge/discharge capacity is improved, but crystal growth is insufficient
Solution Approach 1:
The patent applies preliminary action by first forming a lithium metal composite oxide with controlled composition (0 < x < 0.5) that provides a stable crystal framework. This preliminary structure formation creates a foundation that supports subsequent over-lithiation while maintaining crystal integrity and enabling continued crystal growth to achieve 1 μm to 60 μm primary particle diameter.
Solution Approach 2:
The patent utilizes parameter changes by optimizing the lithium content parameter (x) in stages: first controlling x between 0 and 0.5 for base structure formation and crystal growth, then adding additional lithium to achieve over-lithiation (x > 0.5). This staged parameter adjustment ensures both adequate crystal growth and high charge/discharge capacity.
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 method allows for the production of over-lithiated layered lithium metal composite oxides with increased primary particle diameter and tap density, enhancing volumetric energy density and charge/discharge efficiency, making them suitable for high-performance lithium-ion cells, especially for vehicular applications.
Implementation Method 1
A production method involving calcining a lithium metal composite oxide with a specific composition and then mixing it with a lithium compound to enhance crystal growth and increase primary particle diameter
Data Source
AI summary
A positive electrode material for a lithium-ion cell, comprising an over-lithiated layered lithium metal composite oxide that provides the positive electrode material for a lithium-ion cell. Also, a method for manufacturing an over-lithiated layered lithium metal composite oxide represented by the general formula Li1+xM1−xO2, where x is 0.10 or more and 0.33 or less, and M includes Mn and at least one element selected from the group consisting of Ni, Co, Al, Mg, Ti, Fe and Nb, wherein the method includes a step of mixing a lithium metal composite oxide represented by the general formula Li1+xM1−xO2, where x is −0.15 to 0.15, and M includes Mn and at least one element selected from the group consisting of Ni, Co, Al, Mg, Ti, Fe and Nb, with a lithium compound to obtain a mixture and calcining the mixture to obtain the over-lithiated layered lithium metal composite oxide.