Oxygen molecule dissociation on carbon nanostructures with different types of nitrogen doping

Energy barrier of oxygen molecule dissociation on carbon nanotube or graphene with different types of nitrogen doping is investigated using density functional theory. The results show that the energy barriers can be reduced efficiently by all types of nitrogen doping in both carbon nanotubes and graphene. Graphite-like nitrogen and Stone-Wales defect nitrogen decrease the energy barrier more efficiently than pyridine-like nitrogen, and a dissociation barrier lower than 0.2 eV can be obtained. Higher nitrogen concentration reduces the energy barrier much more efficiently for graphite-like nitrogen. These observations are closely related to partial occupation of {\pi}* orbitals and change of work functions. Our results thus provide useful insights into the oxygen reduction reactions.Comment: Accepted by Nanoscal

Preparation of carbon–sulphur composite electrodes by solution impregnation and application to all-solid-state lithium–sulphur batteries

[EN] All-solid-state lithium–sulphur batteries have attracted attention because of their high theoretical capacity and suppression of polysulphide dissolution in organic liquid electrolytes. In this study, sulphur–carbon composites were prepared by impregnating sulphur and a solid electrolyte into the pores of carbon particles using the liquid phase. First, sulphur was impregnated into porous carbon using sulphur-dissolved in toluene and the solvent was subsequently removed. Then, sulphur–carbon composites with and without heat treatment at 155 °C were prepared. Solid electrolyte (SE, Li6PS5Cl) was impregnated into the sulphur–carbon composites using an ethanol solution of Li6PS5Cl. All-solid-state lithium–sulphur batteries were fabricated using the solid electrolyte–sulphur–carbon composites and Li2S–P2S5 solid electrolyte. The batteries showed almost the same capacity despite heating and not heating at 155 °C after sulphur solution impregnation.The authors thank Mr Hikaru TOKIWA for his support for the charge–discharge measurement.Peer reviewe