Fabrication of ultrafine ZnFe2O4 nanoparticles decorated on nitrogen doped carbon nanofibers composite for efficient adsorption/electrocatalysis effect of lithium-sulfur batteries

Abstract Lithium-sulfur (Li-S) battery is regarded as a hotspot in the research field of next-generation energy storage with a theoretical specific capacity of 1675 mAh g−1 and an energy density of 2600 Wh g−1. However, the short cycle life and poor lithium transport kinetics are restricted its real-world applications. Hence, the combination of electrospinning technology and subsequent hydrothermal method acts as an effective strategy to synthesize the ultrafine zinc ferrite nanoparticles decorated on nitrogen functionalized porous carbon nanofibers (ZFO/NCFs). Three-dimensional ZFO/NCFs act as self-standing electrode for Li-S batteries. The presence of ZFO nanoparticles is beneficial for adsorbing lithium polysulfides and inhibiting the shuttle effect. Additionally, ZFO nanoparticles exhibit an excellent catalytic effect of the polysulfides conversion in redox reactions. As a result, the cell of ZFO/NCFs delivers a high initial discharge capacity of 1100.8 mAh g−1 and after 300 cycles the discharge capacity reaches 789.7 mAh g−1 (coulombic efficiency: average 98.7%) at 0.2 C under 5.75 mg sulfur loading. Moreover, the initial capacity of ZFO/NCFs is 10.23 mAh and remains 7.21 mAh at 12.15 mg sulfur loading after 120 cycles. Hence, ZFO/NCFs contribute to adsorption and catalysis, which shows a promising exploration for the design of cathode materials of Li-S batteries.