Carbon/MoO₂ Composite Based on Porous Semi-Graphitized Nanorod Assemblies from In Situ Reaction of Tri-Block Polymers

Abstract

Ordered mesoporous carbon materials with a semi-graphitized structure have been synthesized by directly employing a tri-block copolymer as a structure directing agent and carbon source to form mesoporous carbon. Poly(ethylene oxide)20-poly(propylene oxide)70-poly(ethylene oxide)20 (EO20PPO70EO20), or “P123”, was cross-linked in the channels of mesoporous silicate, carbonized, and graphitized. Extraction of the silica produces a mesoporous graphitic carbon replica. The graphitization of carbon was realized by employing transition metals (Fe, Co, Ni) as a catalyst in a reducing atmosphere. Of the three transition metal catalysts, nickel was found to be the best candidate in terms of preserving structural order. All three nanoporous carbon materials have 3 orders higher conductivity and better thermal stability than non-graphitic carbon. A composite of ordered mesostructured carbon/metallic MoO2 (63.7 wt % MoO2) was prepared and examined as a negative electrode in a lithium rechargeable battery. The material exhibited a reversible capacity of 760 mA·h/g in the voltage window 3.0−0.0 V.