Radical-polymerized chemical vapor deposition, a new bottom-up method, was developed to produce graphene nanoribbons (GNRs) efficiently, despite the use of extremely low vacuum. Using this technique, a systematic synthesis of a multilayered high-density array of width-controlled sub-1 nm GNRs on a metal surface, with width-dependent band gap, is made possible. GNR films transferred onto insulating substrates behave as an excellent photoconductor.
In this paper we investigate the effect of heat treatment of carbon papers on Ti-Mn redox system. The heat treatment improves the redox reaction kinetics of carbon paper electrode for both positive and negative half-cell. It is considered that the enhanced kinetic performance is attributed to the increased wettability of carbon surface, because a significant increase in the surface area was not observed. In the full-cell evaluation, mass transport loss increased significantly with increasing the state of charge. It is considered that the precipitation of MnO 2 caused decrease of reactants and prevented reactants diffusion. The low kinetics of negative halfcell limited the cell performance. The cell performance has been greatly improved by using a high capacitance carbon felt as negative electrode. A high energy efficiency of 83.2% at current density of 100 mA cm -2 was obtained in a single cell test.
In this work, we investigate the effect of thickness and pretreatment of Nafion membranes on the performance of the Ti/Mn redox flow battery. Nafion membranes of various thicknesses (N-115, NR-212 and NR-211) were evaluated. The charge-discharge test showed that the voltage efficiency increased with a thinner membrane, while the coulombic efficiency was not so much dependent on the thickness of membrane. A high energy efficiency of 83.9% at 100 mAcm -2 was obtained with NR-211 (25 m). With the pre-treatment of NR-211 by soaking in deionized water at 75 ºC for 18 hours, the energy efficiency further increased only at a higher current density of 200 mAcm -2 due to the increased ion permeation rates. The highest energy efficiency 84.3% at 200 mAcm -2 was achieved combined with a highly reactive electrode. The relatively low permeability of Ti 3+ and Mn 3+ contributed to the improved performance with thin and pre-treated Nafion membranes.
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