A 3D Nitrogen‐Doped Graphene/TiN Nanowires Composite as a Strong Polysulfide Anchor for Lithium–Sulfur Batteries with Enhanced Rate Performance and High Areal Capacity

Abstract

Abstract Lithium–sulfur (Li–S) batteries have attracted remarkable attention due to their high theoretical capacity of 1675 mAh g −1 , rich resources, inexpensiveness, and environmental friendliness. However, the practical application of the Li–S battery is hindered by the shuttling of soluble lithium polysulfides (LiPSs) and slow redox reactions. Herein, a 3D nitrogen‐doped graphene/titanium nitride nanowires (3DNG/TiN) composite is reported as a freestanding electrode for Li–S batteries. The highly porous conductive graphene network provides efficient pathways for both electrons and ions. TiN nanowires attached on the graphene sheets have a strong chemical anchor effect on the polysulfides, which is proved by the superior performance and by density functional theory calculations. As a result, the 3DNG/TiN cathode exhibits an initial capacity of 1510 mAh g −1 and the capacity remains at 1267 mAh g −1 after 100 cycles at 0.5 C. Even at 5 C, a capacity of 676 mAh g −1 is reached. With a high sulfur loading of 9.6 mg cm −2 , the 3DNG cathode achieves an ultrahigh areal capacity of 12.0 mAh cm −2 at a high current density of 8.03 mA cm −2 . This proposed unique structure gives a bright prospect in that high energy density and high power density can be achieved simultaneously for Li–S batteries.