Composite Cathode Material Combining Layered and Spinel Phases
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Solution Overview
Problem
Lithium batteries face challenges in maintaining structural stability and preventing discharge voltage decay due to repeated charging and discharging, which affects their lifespan and capacity characteristics, especially at high voltages.
Innovation Solution
A composite positive electrode active material with a layered structure and a spinel structure is integrated, where the spinel phase is intermixed into the layered structure, enhancing structural stability and improving lithium ion conductivity, thereby reducing voltage decay and increasing lifespan and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a positive electrode active material is used to achieve high capacity, then the battery capacity increases, but the discharge voltage decays due to repeated charging and discharging
Solution Approach 1:
The patent applies composite materials by combining layered LiMO2 and spinel LiMe2O4 structures in a composite positive electrode active material. The layered structure provides high capacity while the spinel structure provides structural stability during cycling, preventing voltage decay. This composite approach resolves the contradiction between achieving high capacity and maintaining discharge voltage stability through repeated charging and discharging.
2Duration of action of moving object
If the positive electrode active material undergoes repeated charging and discharging, then the battery lifespan increases, but the structural stability deteriorates leading to voltage decay
Solution Approach 1:
The composite structure combining layered and spinel phases provides both long lifespan and structural stability. The spinel phase acts as a structural scaffold that maintains stability during repeated cycling, enabling long battery lifespan without structural degradation or voltage decay.
Solution Approach 2:
The patent applies local quality by having different regions with different structures - the layered LiMO2 regions provide high capacity while the spinel LiMe2O4 regions provide structural stability. This local differentiation allows the material to simultaneously achieve long lifespan and maintain structural stability during repeated charging and discharging.
3Power
If high voltage is used to increase power density, then the battery power increases, but the structural stability of the positive electrode deteriorates
Solution Approach 1:
The composite of layered and spinel structures enables high power operation at high voltage while maintaining structural stability. The spinel phase's inherent stability prevents structural degradation during high-voltage charging, allowing the battery to operate at high power densities without compromising electrode integrity.
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 composite positive electrode active material significantly improves the structural stability and lifespan of lithium batteries by maintaining high voltage stability and reducing discharge voltage decay, leading to enhanced performance and safety characteristics.
Implementation Method 1
the spinel phase is intermixed into the layered structure, enhancing structural stability and improving lithium ion conductivity
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A composite positive electrode active material includes: a first metal oxide that has a layered structure and is represented by Formula 1; and a second metal oxide that has a spinel structure and is represented by Formula 2, wherein the composite positive electrode active material includes a composite of the first metal oxide and the second metal oxide: Formula 1 LiMO2 Formula 2 LiMe2O4 wherein, in Formulas 1 and 2, M and Me are each independently at least one element selected from Groups 2 to 14 of the periodic table, and a molar ratio of Li/(M+Me) in the composite is less than 1.