Li-Mn-Rich Positive Electrode Material for Stable O-Redox Capacity
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Solution Overview
Problem
The demand for large-sized, high-capacity, and high-energy-density rechargeable lithium batteries has increased, but the supply of transition metals like nickel, cobalt, and manganese is insufficient, leading to high costs and issues with voltage decay and energy density.
Innovation Solution
A lithium-manganese-rich positive electrode active material is developed, represented by Chemical Formula 1, which combines a solid-solution phase and a composite phase to achieve high capacity through O-redox while minimizing voltage drop and energy density decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-manganese-rich material with high O-redox capacity is used, then high capacity is achieved, but voltage decay and energy density decrease occur
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio of O-redox capacity to total capacity within 5-20%, and adjusting the lithium content parameter x within 0.05-0.20, to optimize the balance between capacity and energy density, preventing excessive voltage decay while maintaining high capacity
Solution Approach 2:
The patent uses composite materials by creating a lithium-manganese-rich material with a layered structure containing both transition metal oxidation-reduction sites and oxygen oxidation-reduction sites, forming a composite functional structure that balances capacity and voltage stability
2Quantity of substance
If lithium-manganese-rich material with high O-redox capacity is used, then high capacity is achieved, but cycle-life characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the O-redox capacity ratio to 5-20% and lithium content x to 0.05-0.20, which stabilizes the crystal structure during cycling and prevents excessive oxygen release, thereby improving cycle-life characteristics while maintaining high capacity
Solution Approach 2:
The patent converts the potentially harmful excessive oxygen release from O-redox into a beneficial controlled oxygen oxidation-reduction process by limiting the O-redox capacity ratio to 5-20%, transforming the voltage decay and structure deterioration problem into a stable cycling performance
3Quantity of substance
If transition metals such as nickel, cobalt, and manganese are increased to achieve high capacity, then energy density improves, but cost increases due to supply insufficiency
Solution Approach 1:
The patent applies this principle by using lithium-manganese-rich material with high manganese content and controlled O-redox capacity, replacing expensive nickel and cobalt with more abundant and cheaper manganese, achieving cost reduction while maintaining high capacity through the unique O-redox mechanism
Solution Approach 2:
The patent applies parameter changes by optimizing the lithium content x (0.05-0.20) and O-redox capacity ratio (5-20%), which enables high capacity achievement through controlled oxygen oxidation-reduction, reducing dependence on expensive transition metals like nickel and 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 material achieves high capacity characteristics due to O-redox, reduces voltage drop and energy density decrease, and improves cycle-life characteristics, making it a cost-competitive option for rechargeable lithium batteries.
Implementation Method 1
having a layered structure and thus expresses high capacity by applying a new principle referred to as oxygen oxidation-reduction (O-redox) as well as an existing transition metal oxidation-reduction
Data Source
AI summary
Provided are a positive electrode active material for a rechargeable lithium battery including a compound represented by Chemical Formula 1, a positive electrode including the same, and a rechargeable lithium battery. In Chemical Formula 1, 0<a<1, 0.03≤x≤0.2, 0.35≤y≤0.7, 0<b<1, 0<c<1 and 0.5≤z≤1.0.a[Li1+x(NiyMn1-y)1-xO2]+(1-a)[b(LiNizMn1-zO2)+c(Li2MnO3)].[Chemical Formula 1