Zinc acetate activation-enhanced performance of hollow nano silica/carbon composite nanofibers for lithium-sulfur batteries

Abstract

Here we develop a facile and scalable method to prepare silica/activated carbon nanofibers (SiO2/ACNFs) via electrospinning a mixture of PAN and hollow SiO2 nanospheres with following heat treatment, during which Zn(CH3COO)2 activation and PAN carbonization are simultaneously completed. When applied in lithium sulfur battery, the coin cells using S/SiO2/ACNF composites as cathode material exhibit a high discharge specific capacity and long cycling life. The specific capacity at 0.5 and 1 C rates after 300 cycles still remains at 584 and 513 mA h g−1, respectively, and the corresponding capacity decay is just 0.09% at 0.5 C and 0.13% at 1 C per cycle. The Zn(CH3COO)2 activation benefits sulfur loading and volume expansion suppression by creating numerous hierarchical pores in carbon nanofibers. Additionally, hollow SiO2 nanospheres contribute to restrain the “shuttle effects” by adsorbing and releasing polysulfides reversibly. This kind of SiO2/ACNF material and its fabrication method hold high potential for Li-S battery.