Highly sulfur-rich polymeric cathode materials via inverse vulcanization of sulfur for lithium-sulfur batteries

Abstract

In the present study, a new polythiophene derivative bearing an acryloyloxy moiety in the side chain as a functional co-monomer, poly (3-[(2-acryloyloxy) methyl]) thiophene (PAMT), was synthesized to be used for the inverse vulcanization method with elemental sulfur (S8). Highly sulfur-rich graft materials, S-poly (3-[(2acryloyloxy) methyl]) thiophenes (52 and 74%) (S-PAMT), were prepared by inverse vulcanization of PAMT with different feed ratios of molten sulfur. Their structural characterizations were carried out by using appropriate standard spectroscopic methods such as FT-IR, DSC, TGA, SEM as well as XPS. The electrochemical performance of S-PAMT (74%) as a Li-S battery cathode material was evaluated. It was found that the fabricated cells delivered around 400 mAh.g(-1) stable capacity at a C/5 current density over 100 cycles. Electrochemical impedance spectroscopy (EIS) was also performed before and after cycling to further investigate the lithium storage mechanism of S-PAMT (74%).