Lithium Battery Electrode Functional Layer for Fast-Charge Stability
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Solution Overview
Problem
The challenge in manufacturing thick film electrodes for rechargeable lithium batteries is the difficulty in maintaining ion and electron mobility in the thickness direction, which is exacerbated by lithium precipitation during rapid charging.
Innovation Solution
The introduction of a functional layer containing lithium-containing polyoxazoline on the electrode active material layer improves the reversibility of lithium deposition, enhances lithium ion transfer, and stabilizes the solid-electrolyte-interface (SEI) by promoting the formation of an LiF-rich 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 mobility in the thickness direction deteriorates
Solution Approach 1:
The patent applies local quality by creating a functional layer with specific properties (lithium-containing polyoxazoline) at the electrode surface interface, while maintaining thick film structure in the bulk. This functional layer has different composition and properties from the bulk active material, optimizing local conditions for lithium ion deposition and transport without compromising overall energy density
Solution Approach 2:
The patent uses composite materials by combining the active material with lithium-containing polyoxazoline in the functional layer. This composite structure integrates the high capacity of thick active material films with the ion-conducting and stabilizing properties of the polyoxazoline component, achieving both high energy density and good ion mobility
2Speed
If rapid charging is performed to utilize rapid movement of lithium ions, then charging speed increases, but lithium precipitation occurs at negative electrodes due to current concentration and overpotential
Solution Approach 1:
The lithium-containing polyoxazoline functional layer acts as an intermediary between the electrolyte and the active material. It mediates lithium ion deposition by providing a favorable interface that promotes uniform nucleation and growth, reducing current concentration and overpotential effects that lead to precipitation during rapid charging
Solution Approach 2:
The patent changes the chemical composition and structure of the electrode surface through the functional layer, modifying parameters such as surface energy, wettability, and lithium ion affinity. These parameter changes create optimal conditions for reversible lithium deposition even at high charging rates
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
This solution improves the cycle-life characteristics and stability of rechargeable lithium batteries under rapid charging conditions by reducing lithium precipitation and enhancing the electrical conductivity and structural integrity of the electrodes.
Implementation Method 1
enhances lithium ion transfer
Implementation Method 2
stabilizes the solid-electrolyte-interface (SEI) by promoting the formation of an LiF-rich SEI
Implementation Method 3
improves the reversibility of lithium deposited on a negative electrode during rapid charging
Data Source
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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.