Positive Electrode Composition for High-Voltage Battery Cycle Life
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Solution Overview
Problem
Rechargeable lithium batteries experience deterioration and reduced cycle-life due to phase changes in the positive electrode active material caused by high voltage operation, leading to side reactions and decreased capacity.
Innovation Solution
Incorporation of boron nitride (BN) and polyethylene oxide (PEO) in the positive electrode to trap decomposition products and adsorb active oxygen, maintaining lithium ionic conductivity and preventing electrode deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the upper limit charge voltage is increased to achieve high energy density and high capacity, then the battery capacity increases, but the positive electrode active material undergoes phase change and side reactions are accelerated, causing deterioration and reduced cycle-life
Solution Approach 1:
A coating layer comprising boron nitride and polyethylene oxide is formed on the surface of the positive electrode active material. This coating layer acts as an intermediary between the positive electrode active material and the electrolyte, preventing direct harmful interactions while allowing lithium ion transport, thereby suppressing side reactions and electrode deterioration during high voltage charging operations
Solution Approach 2:
The upper limit charge voltage is set to 4.5 V or higher, representing a parameter change that enables high energy density operation. The coating layer composition (boron nitride and polyethylene oxide) is specifically designed to remain stable and effective at these elevated voltages, preventing the phase changes and side reactions that would normally occur
2Use of energy by moving object
If the upper limit charge voltage is increased to achieve high energy density, then lithium ionic conductivity is maintained, but active oxygen is generated causing side reactions and electrode deterioration
Solution Approach 1:
The coating layer converts the harmful effect of active oxygen generation into a beneficial outcome by providing a stable interface that suppresses side reactions. The boron nitride and polyethylene oxide components create a protective environment that prevents active oxygen from causing deterioration, while still allowing the high voltage operation needed for lithium ionic conductivity
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 cycle-life characteristics of rechargeable lithium batteries by reducing electrode deterioration while maintaining conductivity, especially at high voltages above 4.5 V.
Implementation Method 1
Incorporation of boron nitride (BN) and polyethylene oxide (PEO) in the positive electrode to trap decomposition products and adsorb active oxygen
Implementation Method 2
Incorporation of boron nitride (BN) and polyethylene oxide (PEO) in the positive electrode to trap decomposition products and adsorb active oxygen, maintaining lithium ionic conductivity
Data Source
AI summary
The present disclosure discloses a positive electrode including a current collector, and a positive electrode active material layer on the current collector. The positive electrode active material layer includes a positive electrode active material, boron nitride, and polyethylene oxide. The present disclosure also discloses a rechargeable lithium battery including the positive electrode.