tailieunhanh - Báo cáo hóa học: "Origin of Capacity Fading in Nano-Sized Co3O4 Electrodes: Electrochemical Impedance Spectroscopy Study"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Origin of Capacity Fading in Nano-Sized Co3O4 Electrodes: Electrochemical Impedance Spectroscopy Study | Nanoscale Res Lett 2008 3 390-394 DOI S11671-008-9176-7 NANO EXPRESS Origin of Capacity Fading in Nano-Sized Co3O4 Electrodes Electrochemical Impedance Spectroscopy Study Jin-Gu Kang Young-Dae Ko Jae-Gwan Park Dong-Wan Kim Received 26 August 2008 Accepted 11 September 2008 Published online 25 September 2008 to the authors 2008 Abstract Transition metal oxides have been suggested as innovative high-energy electrode materials for lithium-ion batteries because their electrochemical conversion reactions can transfer two to six electrons. However nano-sized transition metal oxides especially Co3O4 exhibit drastic capacity decay during discharge charge cycling which hinders their practical use in lithium-ion batteries. Herein we prepared nano-sized Co3O4 with high crystallinity using a simple citrate-gel method and used electrochemical impedance spectroscopy method to examine the origin for the drastic capacity fading observed in the nano-sized Co3O4 anode system. During cycling AC impedance responses were collected at the first discharged state and at every subsequent tenth discharged state until the 100th cycle. By examining the separable relaxation time of each electrochemical reaction and the goodness-of-fit results a direct relation between the charge transfer process and cycling performance was clearly observed. Keywords Nano-sized Co3O4 Li-ion batteries Capacity fading Electrochemical impedance spectroscopy Charge transfer reaction Introduction The development of rechargeable lithium-ion batteries with higher specific capacity higher power density and longer cycle life is one of the key issues in the field of portable . Kang . Ko . Park . Kim H Nano-materials Research Center Nano-science Research Division Korea Institute of Science and Technology Seoul 136-791 South Korea e-mail dongwan1@ energy storage devices. The nanostructuring of electrode materials has therefore recently attracted much attention due to the short transport .