Su Huaneng

By Qian Xu, Chunzhen Yang and Huaneng Su

The widespread utilization of nonaqueous redox flow batteries is hindered by the low performance. Including some kinds of additives in electrolyte is a possible and facile solution. In this chapter, the effects of carbon dioxide gas, EC/DMC, and antimony ions on the electrochemical performance of nonaqueous redox flow batteries are disclosed. The results show that the ohmic resistance of the deep eutectic solvent (DES) electrolyte reduces significantly when adding carbon dioxide gas and EC/DMC, the percentage of reduction increases with the volume percentage of EC/DMC in electrolyte, and the reaction kinetics almost keeps unchanged for carbon dioxide gas and EC/DMC additives. For the additive of antimony ions, the electrochemical reaction kinetics of active redox couple is enhanced, the diffusion coefficient of active ions also increases, and the charge transfer resistance decreases. The antimony ions electrodeposited on the surface of graphite felt contribute a catalytic effect on the electrochemical reaction so as to improve the performance. However, due to the trade-off between the enhanced kinetics and reduced active surface area, the optimum concentration of antimony ions is found to be 15 mM. In addition, the flow battery assembled with negative electrolyte containing antimony ions exhibits 31.2% higher power density than that of pristine DES electrolyte.

Part of the book: Redox

By Adebare Nurudeen Adewunmi, Sabejeje Akindeji Jerome, Su Huaneng and Lindiwe Eudora Khotseng

This book chapter reports on various catalyst synthesis methods (impregnation, polyol, modified polyol, and microwave-assisted modified polyol methods) to determine which method would result in the most electrochemically active platinum-ruthenium (PtRu) electrocatalyst supported on multi-walled carbon nanotubes (MWCNTs) for methanol oxidation reaction in an acidic medium. Different techniques were used to characterize the synthesized catalysts, including the high-resolution transmission electron microscope used for morphology and calculating particle sizes, and X-ray diffraction for determining crystalline sizes. The electroactive catalyst surface area, ECSA of the electrocatalysts was determined using cyclic voltammetry (CV), while the electroactivity, electron kinetics, and stability of the electrocatalysts towards methanol oxidation were evaluated using CV, electrochemical impedance spectroscopy, and chronoamperometry, respectively. The microwave-assisted modified polyol method produced the PtRu/MWCNT electrocatalyst with the most enhanced electrocatalytic activity compared to other PtRu/MWCNT catalysts produced by the impregnation, polyol, and modified polyol methods.

Part of the book: Electrocatalysis and Electrocatalysts for a Cleaner Environment