Nitrogen-Rich Free-Standing Carbon Cathode for Improved Lithium-Sulfur Battery Performance

Abstract

A study on the production of free-standing carbon cathode is an attractive method to improve the low active material ratio, which is a problem with existing Li-S batteries. This work introduces a free-standing carbon material with superior porosity properties for enhanced Li-S battery performance. The free-standing carbon cathode synthesized in this study shows outstanding physical stability by showing superior elastic properties based on a porous structure. Additionally, the free-standing cathode made through electrospinning of NaBH4 and polyacrylonitrile (PAN) has a high nitrogen atom equivalent to about 20%. This in turn inhibits the shuttle phenomenon of polar lithium polysulfides, which is highly soluble in electrolyte, based on strong chemical adsorption ability between, and at the same times improves conductivity to deliver high specific capacity at high current densities. As a result, the free-standing electrode with 2.54 mg cm−2 sulfur loading exhibited a capacity of about 650 mAh g−1 at 5.0 C. By maximizing the advantages of the free-standing electrode, the areal loading of the active material has been increased to 6.11 mg cm−2, which delivers an areal capacity of 3.1 mAh cm−2 at 500th.