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.