Enhanced cycling stability of Li–sulfur battery composites by low pressure penetration of PEDOT:PSS coating

Abstract

A lithium sulfur composite electrode (SCPV) is prepared by in situ permeation of poly (3,4-dioxyethiophene):poly(styrene sulfonate) (PEDOT:PSS) with a thickness of about 10 nm onto the surface of a SC (sulfur and carbon nanotubes) electrode via a low pressure (3.3 kPa) method. The SCPV electrode exhibits a discharge capacity of 1320.0 mA h g⁻¹, which is higher than that of the SC electrode (1265.8 mA h g⁻¹) at 0.1C; furthermore, it exhibits a discharge capacity of 604.9 mA h g⁻¹, which is almost twice that of the SC electrode (306.8 mA h g⁻¹) at 2C, and it is due to the fact that PEDOT:PSS gel polymers store large amounts of electrolytes and have excellent electronic and ionic conductivities. However, the discharge capacity of a SCPV cathode remains at 91.87% after 200 cycles at 0.5C, which is more than twice that of the SC cathode (44.70%); this superior cycling stability is mainly due to the in situ fixation of PEDOT:PSS inside the SC electrode, which inhibits the shuttle effect and volume change during the cycling process, thus improving the cycling stability.