Lithium Manganese Oxide Cathode with Boron Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium cobalt oxide cathodes have limited electric capacity and structural instability, while lithium manganese oxides prepared at high temperatures have unstable structures, and those at low temperatures have reduced cycle characteristics due to increased specific surface area.
Innovation Solution
A cathode active material comprising lithium manganese oxide with a spinel structure and boron elements, having primary particles of 3-6 μm diameter and a specific XRD peak intensity ratio, is prepared by mixing lithium, manganese, and boron-based compounds and calcinating at 700-900°C, enhancing crystallinity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If lithium manganese oxide is prepared at high temperature, then the structure is more stable, but the specific surface area increases and cycle characteristics deteriorate
Solution Approach 1:
The patent changes the preparation temperature parameter from conventional high temperature (900-1100°C) to low temperature (700-900°C), which reduces the specific surface area and improves cycle characteristics while maintaining structural stability through boron addition
Solution Approach 2:
Boron element acts as an intermediary substance that mediates between temperature and structural stability. The boron is disposed inside and on surfaces of primary particles, stabilizing the spinel structure at low preparation temperatures without increasing specific surface area
2Quantity of substance
If lithium cobalt oxide is used as cathode active material, then the electric capacity can be increased, but the cost increases and structural stability decreases
Solution Approach 1:
The patent replaces expensive lithium cobalt oxide with cheaper lithium manganese oxide, accepting the shorter operational life of manganese oxide but extending it through boron stabilization, achieving cost reduction while maintaining adequate longevity
Solution Approach 2:
The patent creates a composite system by incorporating boron element into lithium manganese oxide structure, combining the low cost and high capacity of manganese oxide with the structural stability normally provided by cobalt oxide
3Productivity
If the primary particle diameter is reduced, then the specific surface area increases and reactivity improves, but cycle characteristics and high-temperature stability deteriorate
Solution Approach 1:
The patent optimizes the primary particle diameter parameter to a specific range (3-6 μm) that balances reactivity and cycle characteristics, and changes the preparation temperature to low temperature (700-900°C) to control specific surface area
Solution Approach 2:
Boron element serves as a stabilizing intermediary on particle surfaces, allowing smaller particles to maintain stability by preventing surface degradation and manganese dissolution, thus enabling high reactivity without sacrificing cycle life
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 resulting lithium battery exhibits improved charge and discharge characteristics, high-temperature stability, and suppressed manganese leakage, leading to enhanced performance and longevity.
Implementation Method 1
a lithium manganese oxide comprising primary particles having a spinel structure in which an X-ray diffraction (XRD) peak intensity ratio of I(111)/I(311) is 1.0 or more; and a boron element disposed on at least one position selected from the group consisting of inside the primary particles and on surfaces of the primary particles
Implementation Method 2
calcinating the dry mixture at a temperature of from 700 °C to 900°C
Implementation Method 3
enhancing crystallinity and stability
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A cathode active material including: a lithium manganese oxide of which primary particles has a diameter of 1µm or more and which has a spinel structure in which an X-ray diffraction (XRD) peak intensity ratio of I(111)/I(311) is 1.0 or more; and a boron element disposed at least one position selected from the group consisting of inside the primary particles and on surfaces of the primary particles.