Organometallic-Derived Carbon (ODC)-Metal Nano-Oxide Composites as Improved Electrode Materials for Supercapacitors

In the search for the new generation of electrochemical energy storage materials, a novel and straightforward synthetic route for porous carbons and metal oxide nanoparticle composites based on the chlorination of the organometallic compounds Ni(C₅H₅)₂ and Mn(C₅H₇O₂)₂ at moderate temperatures, followed by hydrothermal treatment, has been developed. Electrochemical measurements in a three-electrode configuration show that, in both composites NiO@ODC and Mn₃O₄@ODC, a synergistic effect between the capacitive and pseudocapacitive energy storage mechanisms is observed, thereby improving their electrochemical performance vs pure carbon materials. Electrochemical evaluation of symmetric cells gave gravimetric capacitances of 124 and 130 F g^-1 for NiO@ODC and Mn₃O₄@ODC, respectively. However, the porous structure of the carbon matrix and the higher conductivity of Mn₃O₄, together, were found to be responsible for the superior electrochemical performance of Mn₃O₄@ODC.