Hollow carbon nano-onions with hierarchical porosity derived from commercial metal organic framework

We report on the synthesis of new metal–organic framework derived carbons using a two-step process employing for the first time a commercially available iron-containing metal–organic framework. The resulting carbons consist mainly of highly graphitic shells due to the highly dispersed iron in the precursor structure which catalyzes the formation of graphitic carbon. In addition, a distinct onion-like morphology is observed, with high total pore volumes of up to 1 cc/g and a hierarchically structured porosity in which the hollow cores of the carbon onions are accessible via smaller micro- and mesopores. As a proof of concept we furthermore demonstrate the inherent structure of this carbon being advantageous for the application in lithium–sulfur batteries as a both confining and contacting host for the active material, yielding capacities of up to 550 mAh/g after 40 cycles.