Cathode Precursor Crystal Orientation for Better Lithium Mobility
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Solution Overview
Problem
Conventional lithium cobalt oxide-based positive electrode active materials face limitations due to increased lithium mobility issues and degraded capacity and output characteristics, necessitating a new precursor and active material design that enhances lithium mobility and orientation control.
Innovation Solution
A positive electrode active material precursor is developed with primary particles arranged radially from the center to the surface, featuring a (001) plane angled 20° to 160° relative to the major axis, formed through a co-precipitation process using sodium aluminate to control crystal orientation, resulting in improved lithium mobility and reduced exposure of the (003) plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the (003) plane is arranged parallel to the major axis direction of primary particles to simplify crystal orientation control, then manufacturing precision is improved, but lithium mobility is reduced and capacity characteristics are degraded
Solution Approach 1:
The patent applies asymmetry by deliberately controlling the crystal orientation so that the (003) plane is arranged at a specific angle (30° to 60°) relative to the major axis direction of primary particles, rather than being parallel to it. This asymmetric arrangement breaks the harmful parallel alignment while maintaining manufacturable precision, thereby improving lithium mobility without sacrificing control capability
Solution Approach 2:
The patent changes the orientation parameter of the (003) plane from a parallel arrangement (0° angle) to a specific angled arrangement (30° to 60°) relative to the major axis direction. This parameter change optimizes the crystal orientation to enhance lithium ion transport pathways while maintaining precise manufacturing control through defined angular ranges
2Productivity
If primary particles are arranged radially from center to surface to reduce lithium movement path, then lithium mobility is improved, but the (003) plane parallel arrangement degrades output characteristics
Solution Approach 1:
The patent combines the radial arrangement of primary particles with an asymmetric crystal orientation where the (003) plane is angled at 30° to 60° relative to the major axis direction. This dual asymmetric configuration maintains the short lithium movement path benefits of radial arrangement while preventing the (003) plane from being parallel to the particle surface, thereby preserving output characteristics
3Productivity
If cobalt content is increased to improve capacity characteristics, then discharge capacity is improved, but material cost increases and supply stability decreases
Solution Approach 1:
The patent changes the compositional parameter by optimizing the cobalt content within a specific range (0.3 < Co/(Ni+Co+Mn) < 0.6) rather than using high cobalt content. This parameter optimization achieves satisfactory discharge capacity while reducing material cost and supply risk associated with excessive cobalt usage
Solution Approach 2:
The patent employs composite material design by creating a multi-element system (Ni-Co-Mn) with optimized ratios, where nickel and manganese partially substitute for cobalt. This composite approach maintains electrochemical performance through synergistic effects while reducing dependence on expensive and supply-unstable cobalt
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 solution enhances lithium mobility, leading to improved capacity and output characteristics in lithium secondary batteries by minimizing the (003) plane exposure and optimizing lithium movement paths.
Implementation Method 1
the primary particle includes crystallines in which a (001) plane is arranged in a direction having an angle of 20° to 160° with respect to a major axis direction of the primary particle
Implementation Method 2
the primary particles are arranged in a radial arrangement from a center of a secondary particle toward a surface direction
Implementation Method 3
when the lithium ions are intercalated/deintercalated into/from the positive electrode and the negative electrode
Implementation Method 4
electrical energy is produced by oxidation and reduction reactions when the lithium ions are intercalated/deintercalated
Data Source
AI summary
A positive electrode active material precursor for a secondary battery is in the form of a secondary particle in which a plurality of primary particles are aggregated, wherein major axes of the primary particles are arranged in a direction from a center of the secondary particle toward a surface thereof, wherein the primary particle includes crystallines in which a (001) plane is arranged in a direction having an angle of 20° to 160° with respect to a major axis direction of the primary particle. A method of preparing the positive electrode active material precursor is also provided.