Yong Hao and a team of students published “A Comparison Study of Confinement Effect of PEDOT and CNT for Sulfur Nanocomposites in Li-S Battery Application,” following research work conducted the Summer Undergraduate Research program.
Hao worked with students Nicholas Greco, Michael Ross and Marc Hermann on the research.
Lithium sulfur (Li-S) battery, a technology that has been studied since the 1980s, has yet to be brought into the commercial market. Current challenges to their implementation are namely: large volumetric expansion and shrinkage of S as the cell cycles, the diffusion and dissolution of polysulfides during cycling and sulfur inherently as an insulator. In an attempt to tackle the issues of sulfur as cathode, in this study, sulfur was synthesized via a chemical reaction altering elemental sulfur into nano-sized particles. Conductive polymer PEDOT was chosen for its flexible structure to contain the volumetric expansion of the sulfur¬ nanoparticles (S-NPs). Multi-walled carbon nanotubes (MWCNTs) were selected as the matrix to localize the S-NPs. Polyvinyl-pyrrolidone (PVP), an amphiphilic compound, was used to optimize the size of S-NPs, containing them in a shell to ensure the S-NPs did not aggregate. Results show the system of S-NPs coated in PEDOT to be a suitable sulfur encapsulant, with a minimum 25 wt% of active material comprising the final structure.