SAXS and Raman Study of the Structural Evolution in Hemp Bast Fiber Derived Porous Carbon

Abstract

The aim of this paper is the systematic study of the structural properties evolution of porous carbons derived from hemp bast fiber at the different carbonization temperatures with the next chemical activation procedure under the conditions of additional nitrogen doping and thermal treatment. The comparative analysis of SAXS and Raman spectroscopy data was done. The obtained materials have a turbostratic structure and consist of the ultrasmall graphitic fragments separated by amorphous carbon. It was determined that the carbonization temperature in a range of 800-1000°C causes sharp increase in micropores relative content after carbon treatment with nitric acid. The minimal lateral size of graphitic crystallites (of about 5.5 nm along (002) basal plane) is observed for nitrogen-doped carbon obtained at carbonization temperature of 800°C that corresponds to average aggregates size. The control of activated carbons structural properties allows to increase energy and power densities of electrochemical capacitors as well as to create the preconditions for composite electrode materials obtaining with predictable properties.