Advanced Energy Technologies
Mohsen Babaiee; Mohammad Zarei-Jelyani; Shaghayegh Baktashian; Rahim Eqra
Abstract
A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The ...
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A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The BCF and MCF anodes exhibited adhesion strengths of 1.552 and 1.617 MPa, respectively. The electrochemical studies of BCF and MCF anodes showed that the initial discharge capacity of graphite anode coated on the MCF (323.6 mAh g-1) was about 8 % higher than the BCF anode (299.9 mAh g-1). The BCF anode capacity reached 227.9 mAh g-1 after 100 charge/discharge cycles at 0.5C rate, while this value was 247.7 mAh g-1 for MCF anode. The results of electrochemical impedance spectra demonstrated that the diffusion coefficient of lithium-ion for MCF anode was about 56 % higher than that for BCF anode. On the other hand, the surface modification of the copper current collector reduced the charge transfer resistance of anode from 28.5 Ω to 23.2 Ω.
Advanced Energy Technologies
Mohammad Zarei-Jelyani; Shaghayegh Baktashian; Mohsen Babaiee; Rahim Eqra
Abstract
In recent years, many studies have focused on the active materials of anodes to improve the performance of LIBs, while limited attention has been given to polymer binders, which act as inactive ingredients. However, polymer binders have amazing influence on the electrochemical performance of anodes. ...
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In recent years, many studies have focused on the active materials of anodes to improve the performance of LIBs, while limited attention has been given to polymer binders, which act as inactive ingredients. However, polymer binders have amazing influence on the electrochemical performance of anodes. Herein, to investigate the binding performance between MCMB artificial graphite and the copper current collector, three binders such as PVDF, MSBR, and CMC+SBR were used to prepare the anode electrodes. The mechanical and electrochemical tests were conducted for different MCMB electrodes. The results show that the water-based binders (CMC+SBR and MSBR) made better adhesion properties for the coating on the current collector in comparison with the organic solvent-based binder (PVDF). MCMB anode fabricated with CMC+SBR binder shows the highest discharge capacity and the best rate performance at various C-rates of 0.2C, 0.5C, and 1C that result in the brilliant electrochemical performance. Therefore, artificial graphite anode materials using cheap aqueous CMC+SBR binder instead of toxic solvent like NMP and expensive PVDF improve electrochemical property and reduce the cost of LIBs.
Mohammad Zarei-Jelyani; Mohsen Babaiee; Abdolmajid Ghasemi; Rahim Eqra
Abstract
Traditional vanadium batteries use pure sulfuric acid as electrolyte, but H2SO4 does not absorb enough vanadium ions to make the electrolyte an efficient energy source. This study investigates the effect of hydroxylation process on electrochemical and operational properties of carbon felt electrode in ...
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Traditional vanadium batteries use pure sulfuric acid as electrolyte, but H2SO4 does not absorb enough vanadium ions to make the electrolyte an efficient energy source. This study investigates the effect of hydroxylation process on electrochemical and operational properties of carbon felt electrode in VOSO4 solution with an optimized supporting electrolyte (a mixture of six parts HCl and 2.5 parts H2SO4). Carbon felt electrode was hydroxylated with mixed acids of H2SO4 and HNO3 in a stainless steel autoclave for 6 h. Then thermal treatment of electrode was performed at 400 oC for 5h. Obtained results of cyclic voltammograms showed that when the carbon felt was hydroxylated, both oxidation and reduction peak currents were increased remarkably and the peak potential separation is decreased from 356 mV to 246 mV, suggesting that the electrochemical activity and the kinetic reversibility on HCF electrode were improved compared to the pristine one. According to results of electrochemical impedance spectra, charge transfer resistance (Rct) was calculated to be 648 Ω for pristine carbon felt. The obtained Rct at hydroxylated electrode (176 Ω) shows a decrease of about 73 % in Rct. Charge-discharge profiles of two cells assembled with the pristine carbon felt (cell A), and hydroxylated carbon felt (cell B) showed that energy, voltage and coulombic efficiencies were significantly improved by using the hydroxylated electrodes inside the cell of vanadium redox flow battery.