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.

Retraction: High‐Performance Molybdenum Dioxide‐Based Anode for Dodecane‐Fueled Solid‐Oxide Fuel Cells (SOFCs)

“…In addition to the fuel-cell applications, the high electrical conductivity of MoO 2 -based anodes has been utilized as an alternative anode material for lithium-ion batteries. [25][26][27] Our previous design for the MoO 2 -based anode showed significantly lower initial performance than that displayed by commercial Ni-based SOFCs. [20] The tested MoO 2 -based anode was found to change its surface morphology toward a dense film during the startup process as the cell temperature increased from 25 to 850 8C under a inert gas.…”

The Development of Pseudocapacitive Properties in Nanosized-MoO2

“…Prior research on MoO 2 with graphene or carbon was focused on improving the stability of conversion reactions, [31][32][33][34] but the same system can be used to address the oxidation problems discussed above. High angle XRD of as-synthesized MoO 2 -RGO hybrid materials (Figure 1c (Figures 5b and 5d) indicate that MoO 2 nanoparticles on the RGO sheets also have an oxidized shell on the surface that can again be removed by argon-ion etching, but the fact that the MoO 2 appears to nucleate directly on the GO means that the interface between RGO and MoO 2 is likely to remain unoxidized and thus highly conductive.…”

Rational confinement of molybdenum based nanodots in porous carbon for highly reversible lithium storage

“…The introduction of carbon (e.g., carbon coating) can improve electronic conductivity and accommodate volume variation of oxide electrode materials, which results in improved specific capacity, rate capability and cycling stability of the electrode. 13,19,20 The combination of the abovementioned strategies can further improve the electrochemical performance. There are two primary routes for introducing carbon on nanostructured electrode materials as follows: 1) the coating of materials with carbon after nanostructuring (Scheme 1a1) and 2) the in situ formation of carbon on materials in addition to the simultaneous formation of nanostructures (Scheme 1a2).…”