Nanoscale CuFe2O4 Uniformly Decorated on Nitrogen-Doped Carbon Nanofibers as Highly Efficient Catalysts for Polysulfide Conversion in Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries have been considered one of the most promising energy storage systems, owing to the theoretical specific capacity (1675 mAh g(-1)) and energy density (2600 Wh g(-1)). However, it is challenging to solve the shuttling and low reduction kinetics of lithium polysulfides. Hence, the combination of electrospun and hydrothermal treatments acts as an effective strategy to synthesize copper ferrite nanoparticles decorated on nitrogen doped carbon nanofibers (CF/NC). The resultant material is employed as a positive current collector containing Li2S6 catholyte for Li-S batteries. The addition of CF nanoparticles plays a vital role in capturing polysulfides in both physical and chemical adsorption. Besides, promoted sulfur conversion kinetics are obtained due to the excellent catalytic effect, which enabled significantly improved sulfur utilization, high-rate capability, and cycling stability. Under a 5.75 mg sulfur loading, the cell with CF/NC delivers an excellent cycling stability with 609 mAh g(-1) after 300 cycles at 0.2 C. Even at 12.15 mg high sulfur loading, the high initial capacity of the cell is 9.4 mAh at 0.1 C.

Automated summary

A new material CF/NC was successfully synthesized using a combination of electrospinning and hydrothermal treatment, effectively addressing the issues of shuttling and low reduction kinetics of lithium polysulfides in Li-S batteries. The addition of CF nanoparticles played a key role in capturing polysulfides and promoting sulfur conversion kinetics, resulting in improved sulfur utilization and cycling stability.