Ordered mesoporous silicon carbide-derived carbon for high-power supercapacitors

Abstract

Micro/mesoporous carbon was prepared by chlorination of ordered mesoporous silicon carbide derived from magnesio-thermal reduction of templated carbon-silica precursors. These materials were then used as active materials for electrochemical capacitors and characterized in 1.5 M NEt 4 BF 4 /AN. The electrodes showed outstanding rate capability (90% of capacity retention at 1 V/s and time constant of 1 s) with high specific areal capacitance (0.5 F/cm 2 of electrode), that makes such hierarchical porous carbons promising for high power and energy density supercapacitors.

Effect of Transition Metal Compounds on Amorphous SiC Removal Rates

“…5 shows the survey scan spectra of three SiC surfaces, one polished using an additive-free slurry of silica particles (1 wt%) adjusted to pH 6, the second polished using a slurry containing 0.05 M KMnO 4 and 1 wt% silica particles, also adjusted to pH 6, and the third one polished with a slurry containing 0.05 M KMnO 4 , 2 mM CuSO 4 and 1 wt% silica particles at pH 6. The spectra for the surface polished with silica particles only and in the presence of the KMnO 4 are very similar except for a taller O 1s peak in the case of KMnO 4 , indicating that a much thicker oxide is formed in the presence of KMnO 4 in agreement with earlier reports. Table II shows a comparison of atomic composition (%) of the asreceived SiC surface with surfaces polished using different slurries.…”

“…These data suggest the possibility of strong interaction between the copper and manganese based additives and the a-SiC surface but also emphasize the need for abrasive action to obtain high RRs. 4 as an oxidizer.-Based on the above results, KMnO 4 , a strong oxidizer containing a transition metal compound, was evaluated as an additive to silica dispersions for polishing a-SiC substrates over the pH range 2 to 10 and the results are shown in Fig. 3.…”

“…41,43 Also, Zhang et al 44 showed that KMnO 4 is much better at attacking carbon atoms in carbon nanotubes and oxidize them when compared to H 2 O 2 or HNO 3 . Furthermore, in the neutral and alkaline pH regions, KMnO 4 acts as an oxidizer and converts to MnO 4 2− followed by the formation of a black precipitate (MnO 2 ) via the following reaction:…”

“…These characteristics make them suitable as etch masking layers during advanced semiconductor, solar cell and micro-electro mechanical system (MEMS) fabrication. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Examples of these applications include deep etching of glass or silicon, protection of low-K dielectric films, as a stop layer in STI CMP, etc. 10,12,14 The planar surface necessary to use a-SiC as a hard mask in these applications can be potentially achieved using chemical mechanical planarization (CMP). 14 Since, the a-SiC hard mask layers typically protect an underlying dielectric material, generally SiO 2 , the CMP polish process must be selective to it.…”

Multi-scale modelling of supercapacitors: From molecular simulations to a transmission line model

“…The simulated system consists in a generic electrolyte, i.e. L −1 , which is classically used in experiments 16,17 ), surrounded by two identical nanoporous carbon electrodes placed symmetrically. The position of the carbon atoms inside the electrodes, which are held fixed, were obtained by quenched molecular dynamics by Palmer et al 18 .…”