Spent coffee derived hierarchical porous carbon and its application for energy storage

Abstract

This work addresses the derivation of hierarchical porous carbon material from waste biomass of spent coffee ground (SCG) via a facile pyrolysis/activation process, where the calcination of wet SCG at 800 °C induced pore development, which is attributed to the intrinsic moisture in raw SCG. Further treatment using a HNO3 and H2O2 solution at 80 °C resulted in a hierarchical pore structure of micro- and meso-pores in the carbon material with a high surface area of 1037.52 m2/g. Nitrogen, a rich heteroatom in raw SCG, is self-incorporated well in the carbon skeleton of the resultant porous carbon with a high nitrogen content of 3 w/w%. The prepared hierarchical porous carbon was tested as a material for Li–S batteries, and displayed a capacity of more than 600 mAh g−1 at 0.2 C up to 150 cycles. As a sustainable carbon material, the SCG derived porous carbon, which has abundant heteroatoms of O and N, can be employed as a potential energy storage material.