Composite Electrode Materials for Fast-Charging Li-Ion Capacity Stability
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Solution Overview
Problem
Related-art lithium ion secondary batteries face challenges in maintaining high electric capacity during high-speed charge and discharge, and require improvements in high-temperature stability and safety.
Innovation Solution
The use of an active material layer containing sulfur-modified polyacrylonitrile and lithium-titanium oxide, with specific particle size ratios and content percentages, enhances the battery's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-speed charge and discharge is performed in related-art lithium ion secondary batteries, then power output increases, but electric capacity is reduced
Solution Approach 1:
The patent uses a composite electrode material consisting of sulfur-modified polyacrylonitrile (SPAN) and lithium-titanium oxide (LTO) particles. The SPAN provides high capacity while LTO ensures structural stability and fast ion transport, allowing the battery to achieve both high power output and high electric capacity during fast charge/discharge operations. The composite structure enables synergistic effects where SPAN's high capacity is maintained through LTO's stabilizing framework.
2Quantity of substance
If conventional electrode materials are used to increase electric capacity, then energy density improves, but high-temperature stability deteriorates
Solution Approach 1:
The patent modifies the physical and chemical parameters of the electrode materials by controlling the particle size ratio (SPAN particles larger than LTO particles), sulfur content (30-70 mass%), and specific surface area of the composite material. These parameter optimizations enable the electrode to maintain high electric capacity while achieving superior high-temperature stability through reduced thermal degradation and improved structural integrity.
3Quantity of substance
If sulfur-modified polyacrylonitrile is used as the main active material, then electric capacity increases, but structural stability at high temperature decreases
Solution Approach 1:
The lithium-titanium oxide particles act as an intermediary stabilizing framework within the sulfur-modified polyacrylonitrile matrix. The LTO particles provide structural support and maintain electrode integrity at high temperatures, while the SPAN provides high capacity. The intimate contact between the two materials allows efficient charge transfer while LTO prevents excessive volume expansion of SPAN during cycling.
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 battery achieves high electric capacity during high-speed charge and discharge while maintaining excellent high-temperature stability.
Implementation Method 1
an active material layer containing sulfur-modified polyacrylonitrile and a lithium-titanium oxide is formed on a collector
Data Source
AI summary
Provided is an electrode, including: a collector; and an active material layer formed on the collector, wherein the active material layer contains sulfur-modified polyacrylonitrile and a lithium-titanium oxide, wherein an average secondary particle diameter of the sulfur-modified polyacrylonitrile is larger than an average secondary particle diameter of the lithium-titanium oxide, and wherein a content of the sulfur-modified polyacrylonitrile in the active material layer is from 5 mass % to 85 mass %, and a content of the lithium-titanium oxide in the active material layer is from 5 mass % to 85 mass %.