Synergistic Effect of Carbon Nanofiber/Nanotube Composite Catalyst on Carbon Felt Electrode for High-Performance All-Vanadium Redox Flow Battery Minjoon Park Yang-jae Jung Jungyun Kim Ho il Lee Jeaphil Cho 10.1021/nl402566s.s001 https://acs.figshare.com/articles/journal_contribution/Synergistic_Effect_of_Carbon_Nanofiber_Nanotube_Composite_Catalyst_on_Carbon_Felt_Electrode_for_High_Performance_All_Vanadium_Redox_Flow_Battery/2368303 Carbon nanofiber/nanotube (CNF/CNT) composite catalysts grown on carbon felt (CF), prepared from a simple way involving the thermal decomposition of acetylene gas over Ni catalysts, are studied as electrode materials in a vanadium redox flow battery. The electrode with the composite catalyst prepared at 700 °C (denoted as CNF/CNT-700) demonstrates the best electrocatalytic properties toward the V<sup>2+</sup>/V<sup>3+</sup> and VO<sup>2+</sup>/VO<sub>2</sub><sup>+</sup> redox couples among the samples prepared at 500, 600, 700, and 800 °C. Moreover, this composite electrode in the full cell exhibits substantially improved discharge capacity and energy efficiency by ∼64% and by ∼25% at 40 mA·cm<sup>–2</sup> and 100 mA·cm<sup>–2</sup>, respectively, compared to untreated CF electrode. This outstanding performance is due to the enhanced surface defect sites of exposed edge plane in CNF and a fast electron transfer rate of in-plane side wall of the CNT. 2016-02-18 17:06:23 vanadium redox flow battery electron transfer rate edge plane mA Carbon Felt Electrode surface defect sites energy efficiency electrode materials acetylene gas CF electrode Synergistic Effect discharge capacity Ni catalysts CNT electrocatalytic properties VO CNF cell exhibits