Lithium Battery Electrodes With Polyoxazoline SEI Layer for Fast Charging
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Solution Overview
Problem
The challenge in manufacturing thick film electrodes for rechargeable lithium batteries is not only the difficulty in achieving efficient ion and electron movement in the thickness direction, but also the issue of lithium precipitation during rapid charging, which leads to reduced cycle-life characteristics.
Innovation Solution
The introduction of a functional layer containing lithium-containing polyoxazoline on the electrode active material layer improves the reversibility of lithium deposition during rapid charging, enhancing the cycle-life characteristics and stability of the rechargeable lithium battery through modification of the solid-electrolyte-interface (SEI).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the active material is placed more thickly on the current collector to form thick film electrodes, then energy storage per unit volume increases, but ion and electron movement in the thickness direction becomes more difficult
Solution Approach 1:
The patent divides the thick electrode into multiple thin layers by introducing functional layers containing lithium-containing polyoxazoline. These functional layers are positioned at specific intervals within the thick electrode structure, creating a segmented architecture that facilitates ion and electron transport while maintaining high energy density. The segmentation allows ions to move through multiple pathways rather than traversing a single thick barrier.
Solution Approach 2:
The lithium-containing polyoxazoline functional layer acts as an intermediary substance within the thick electrode structure. This intermediary material facilitates lithium ion transport through the thick electrode by providing conductive pathways, thereby enabling high energy storage while maintaining fast ion movement. The polyoxazoline compound serves as a mediator between the active material and electrolyte, improving overall ion transport efficiency.
2Speed
If rapid charging is performed to meet increasing demand, then charging speed increases, but lithium precipitation occurs at negative electrodes due to current concentration and overpotential
Solution Approach 1:
The patent applies preliminary action by pre-coating the negative electrode with a functional layer containing lithium-containing polyoxazoline before rapid charging occurs. This preliminary modification of the electrode surface creates a protective and conductive interface that prevents lithium precipitation during subsequent rapid charging cycles. The pre-applied functional layer prepares the electrode to handle high current densities without causing lithium dendrite formation.
Solution Approach 2:
The patent changes the chemical and physical parameters of the electrode surface by introducing lithium-containing polyoxazoline. This parameter change modifies the surface properties to reduce overpotential and improve lithium ion insertion/extraction kinetics. The functional layer alters the electrochemical parameters of the negative electrode, enabling rapid charging without lithium precipitation by changing the interfacial properties between electrode and electrolyte.
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 implementation of the lithium-containing polyoxazoline functional layer increases the reversibility of lithium and improves lithium ionic conductivity, resulting in enhanced cycle-life characteristics and stability of the rechargeable lithium battery under rapid charging conditions.
Implementation Method 1
the cycle-life stability of the rechargeable lithium battery can be improved through the SEI film modification
Data Source
AI summary
Disclosed are an electrode for a rechargeable lithium battery, and a rechargeable lithium battery including the same, the electrode including a current collector, an electrode active material layer on the current collector, and a functional layer, wherein the functional layer includes a lithium-containing polyoxazoline.