Cathode Precursor Crystal Tuning for Battery Cycle Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges with deteriorating capacity characteristics and cycle life due to structural deformation of the cathode active material and side reactions with the electrolyte.
Innovation Solution
A cathode active material precursor comprising transition metal hydroxide particles with specific crystal grain size, XRD peak intensity ratio, and oxygen position, along with lithium-transition metal oxide particles, is used to enhance lithium ion mobility and structural stability, thereby improving capacity and cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cathode active material is used in lithium secondary batteries, then high energy density and operating voltage are achieved, but structural deformation occurs leading to deteriorating capacity characteristics and cycle life
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystal grain size of transition metal hydroxide particles to 10 nm to 18 nm in the (001) plane direction and adjusting the XRD peak intensity ratio I(101)/I(001) to 0.7 to 1.3. These specific parameter ranges optimize the cathode material structure to maintain high energy density while preventing structural deformation during cycling, thereby extending battery cycle life.
2Power
If cathode active material is used in lithium secondary batteries, then high operating voltage is achieved, but side reactions with electrolyte occur leading to deteriorating capacity characteristics
Solution Approach 1:
The patent utilizes parameter changes by optimizing the crystal structure parameters of transition metal hydroxide, specifically the crystal grain size (10 nm to 18 nm) and XRD peak intensity ratio (0.7 to 1.3). These parameter adjustments create a more stable cathode material structure that maintains high operating voltage while reducing susceptibility to side reactions with the electrolyte, thus preserving capacity characteristics.
3Speed
If transition metal hydroxide particles with small crystal grain size are used, then lithium ion mobility is improved, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent applies parameter changes by defining a specific crystal grain size range of 10 nm to 18 nm in the (001) plane direction, which is sufficient to improve lithium ion mobility without being excessively small to cause manufacturing difficulties. This optimized parameter range balances performance enhancement with manufacturability.
Solution Approach 2:
The patent applies local quality by specifying different crystal grain size requirements for different crystallographic directions, particularly controlling the size in the (001) plane direction. This directional control allows optimization of lithium ion mobility along specific pathways while maintaining overall structural integrity and ease of manufacture.
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 the capacity and cycle life characteristics of secondary batteries by increasing lithium ion diffusion paths and structural stability, reducing particle cracks and side reactions.
Implementation Method 1
having a crystal grain size of 10 nm to 18 nm in a (001) plane direction as measured by X-ray diffraction (XRD) analysis, and an XRD peak intensity ratio of 0.7 to 1.3
Implementation Method 2
enhancing the capacity and cycle life characteristics of secondary batteries by increasing lithium ion diffusion paths
Data Source
Figure 1~2
AI summary
A cathode active material precursor for a lithium secondary battery according to embodiments of the present disclosure includes transition metal hydroxide particles having a crystal grain size of 10 nm to 18 nm in a (001) plane direction as measured by X-ray diffraction (XRD) analysis, and an XRD peak intensity ratio of 0.7 to 1.3 as defined by Equation 1.