Mesoporous Glassy Carbon Research Articles

Porous Carbon/Tin (IV) Oxide Monoliths as Anodes for Lithium-Ion Batteries

A monolithic, three-dimensionally ordered macroporous/mesoporous carbon/tin (IV) oxide (3DOM/m ) nanocomposite was prepared and tested as an anode material for lithium-ion batteries. A macro-/mesoporous glassy carbon (3DOM/m C) monolith was first synthesized from a triconstituent precursor, using a polymer colloidal crystal and a nonionic surfactant as the templates for macropores and mesopores, respectively. Tin (IV) oxide nanocrystals were then introduced into the mesopores of the carbon monolith via an infiltration-hydrolysis process while maintaining connections between macropores. The composite electrode exhibited superior reversible lithium capacity over a carbon/tin dioxide electrode without any designed mesostructure and also over similarly templated glassy carbon electrodes lacking the tin oxide component. The initial discharge capacity was and remained above for at . The formation of stable solid-electrolyte interphase layers contributed to the good cycleability of 3DOM/m . The structural and morphological changes of the electrode after cycling were evaluated by scanning and transmission electron microscopy and by X-ray diffraction.

Analysis of the microporous texture of a glassy carbon by adsorption measurements and Monte Carlo simulation. Evolution with chemical and physical activation

A mesoporous glassy carbon has been chemically (KOH) and physically (CO 2) activated in order to improve its micropore volume while preserving the well-defined mesopore network. The microporosity of the glassy carbon and the evolution of the micropore texture with activation have been studied by means of Monte Carlo simulation and gas adsorption. Micropore size distributions obtained from simulated adsorption isotherms on slit-shaped pores revealed different accessibilities of methane and nitrogen to the microporous texture of the original sample, indicating the presence of constrictions in the micropore network. Both activating agents are able to increase the micropore volume generating new micropores, although KOH showed to be more effective. While CO 2 treatment preserved some hindrances to the access of nitrogen molecules to the micropores, KOH activation generates a more accessible micropore network. Therefore, chemical activation by KOH is a suitable way to increase the adsorption capacity of glassy carbons while preserving the mesoporous structure. Molecular simulation of adsorption linked to experimental adsorption of different gases, has proven to give very satisfactory results in analysing the evolution of the micropore texture and accessibility of carbon materials by different activation treatments.

Modifications produced by O2 plasma treatments on a mesoporous glassy carbon

A glassy carbon, P3, obtained by carbonization of polyfurfuryl alcohol was used to study the changes produced by oxygen plasma treatments which were compared to those obtained by molecular oxygen. The sample was selected for its well defined mesoporosity. The aim was to study the influence of porosity on the reactivity of the sample in oxygen plasma. The results were compared to previously reported data obtained using a glassy carbon with no macro or mesoporosity. It is concluded that the influence of mesoporosity is almost negligible in such a way that only the external surface was affected by plasma treatment.