TY - JOUR

T1 - Influence of carbon microstructure on the Li–O2 battery first-discharge kinetics

AU - Wijaya, Olivia

AU - Hoster, Harry Ernst

AU - Rinaldi, Ali

N1 - This is the peer reviewed version of the following article: Wijaya, O., Hoster, H. E., and Rinaldi, A. (2017) Influence of carbon microstructure on the Li–O2 battery first-discharge kinetics. Int. J. Energy Res., 41: 889–898. doi: 10.1002/er.3690 which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/er.3690/abstract This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.

PY - 2017/5

Y1 - 2017/5

N2 - Defects in the carbon microstructure have been reported to enhance the discharge performance of Li–O2 battery. However, systematic studies correlating the presence of defects with the discharge kinetics have not addressed the variation of carbon electrode surface areas. In this work, carbon blacks and carbon nanofibers with different defect densities were investigated for their discharge properties. The electrolyte-accessible areas of the carbon electrodes were obtained from Cyclic voltammetry measurements. The microstructure and surface areas of the carbons were characterized by Raman spectroscopy, electron microscopy, and N2 isotherm. Linear sweep voltammetry and galvanostatic discharge experiments consistently demonstrated that graphitic carbons have more negative onset potentials and more negative discharge potentials at the same current density than defective carbons. The linear sweep voltammetry data were normalized to the carbon masses, Brunauer–Emmet–Teller surface areas, and double layer capacitance-derived areas for comparison. Plot of inverse charge transfer resistance and double layer capacitance from electrochemical impedance spectroscopy measurements were used to extract current density values without knowledge of electrode areas. The current densities from impedance measurements exhibited good agreement with the data from linear sweep experiments. The electrochemical experiments conclusively showed that defects on the graphitic microstructure increase the discharge kinetics of the Li–O2 battery.

AB - Defects in the carbon microstructure have been reported to enhance the discharge performance of Li–O2 battery. However, systematic studies correlating the presence of defects with the discharge kinetics have not addressed the variation of carbon electrode surface areas. In this work, carbon blacks and carbon nanofibers with different defect densities were investigated for their discharge properties. The electrolyte-accessible areas of the carbon electrodes were obtained from Cyclic voltammetry measurements. The microstructure and surface areas of the carbons were characterized by Raman spectroscopy, electron microscopy, and N2 isotherm. Linear sweep voltammetry and galvanostatic discharge experiments consistently demonstrated that graphitic carbons have more negative onset potentials and more negative discharge potentials at the same current density than defective carbons. The linear sweep voltammetry data were normalized to the carbon masses, Brunauer–Emmet–Teller surface areas, and double layer capacitance-derived areas for comparison. Plot of inverse charge transfer resistance and double layer capacitance from electrochemical impedance spectroscopy measurements were used to extract current density values without knowledge of electrode areas. The current densities from impedance measurements exhibited good agreement with the data from linear sweep experiments. The electrochemical experiments conclusively showed that defects on the graphitic microstructure increase the discharge kinetics of the Li–O2 battery.

U2 - 10.1002/er.3690

DO - 10.1002/er.3690

M3 - Journal article

VL - 41

SP - 889

EP - 898

JO - International Journal of Energy Research

JF - International Journal of Energy Research

SN - 0363-907X

IS - 6

ER -