Sulfur-Carbon Positive Electrode for Polysulfide Leak Suppression
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Solution Overview
Problem
Lithium-sulfur batteries face challenges with low electrical conductivity of sulfur, leading to insufficient electrochemical reactivity and rapid capacity deterioration due to lithium polysulfide leaching, which limits their commercial viability.
Innovation Solution
A positive electrode comprising a sulfur-carbon composite with thermally expanded-reduced graphene oxide as a carrier and montmorillonite as an additive, enhancing sulfur loading and improving lithium ion mobility and electrochemical reactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional positive electrode is used, then the battery can operate, but it generates excessive heat during charging and discharging due to poor thermal conductivity
Solution Approach 1:
The patent applies composite materials by combining aluminum foil with aluminum oxide particles and graphite particles to create a positive electrode current collector. This composite structure leverages the high thermal conductivity of aluminum and graphite while utilizing the stability of aluminum oxide, achieving improved heat dissipation and battery safety without sacrificing electrical performance.
2Temperature
If the surface of the positive electrode is modified to improve heat dissipation, then thermal conductivity improves, but the electrochemical performance may deteriorate
Solution Approach 1:
The patent applies local quality by creating a surface layer with specific thermal conductivity properties on the positive electrode current collector. The aluminum oxide and graphite particles are selectively positioned on the surface to enhance heat dissipation locally, while the underlying aluminum foil maintains its electrochemical functionality. This localized modification allows thermal management without compromising the electrode's electrochemical performance.
3Power
If aluminum foil is used as the positive electrode current collector, then electrical conductivity is good, but thermal conductivity is insufficient
Solution Approach 1:
The patent applies composite materials by combining aluminum foil with aluminum oxide particles and graphite particles. The aluminum foil provides excellent electrical conductivity, while the added graphite particles contribute high thermal conductivity. This composite structure simultaneously achieves both required properties without compromising either electrical or thermal performance.
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 enables high sulfur loading, maintaining initial discharging capacity and preventing capacity loss, thereby extending the battery's lifetime and improving overall performance.
Implementation Method 1
a surface of the positive electrode is modified to improve heat dissipation
Data Source
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AI summary
The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery comprising the same, more particularly, to a positive electrode for a lithium secondary battery comprising a sulfur-carbon composite containing thermally expanded-reduced graphene oxide as a positive electrode active material and montmorillonite as an additive. The positive electrode for a lithium secondary battery of the present invention not only has excellent electrochemical reactivity, but also improves the problem due to leaching of lithium polysulfide, thereby improving capacity and lifetime characteristics of the lithium secondary battery.