Volume 8, Issue 24 p. 4235-4241
Full Paper

The Effect of Potassium Impurities Deliberately Introduced into Activated Carbon Cathodes on the Performance of Lithium–Oxygen Batteries

Dr. Dengyun Zhai

Dr. Dengyun Zhai

Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 USA

These authors contributed equally to this work.

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Dr. Kah Chun Lau

Dr. Kah Chun Lau

Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 USA

These authors contributed equally to this work.

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Dr. Hsien-Hau Wang

Dr. Hsien-Hau Wang

Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 USA

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Dr. Jianguo Wen

Dr. Jianguo Wen

Electron Microscopy Center, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 USA

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Dr. Dean J. Miller

Dr. Dean J. Miller

Electron Microscopy Center, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 USA

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Dr. Feiyu Kang

Dr. Feiyu Kang

Graduate School at Shenzhen, Tsinghua University, The University Town, Shenzhen, 518055 PR China

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Dr. Baohua Li

Dr. Baohua Li

Graduate School at Shenzhen, Tsinghua University, The University Town, Shenzhen, 518055 PR China

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Dr. Kevin Zavadil

Dr. Kevin Zavadil

Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, NM, 87185 USA

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Dr. Larry A. Curtiss

Corresponding Author

Dr. Larry A. Curtiss

Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439 USA

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First published: 02 December 2015
Citations: 13

Graphical Abstract

Special K: Small amounts of potassium (0.05 to 0.43 weight %) introduced into the activated carbon cathode are found to have a dramatic effect on the performance of the Li–O2 cell. An increased amount of K significantly increases capacity, cycle life, and round trip efficiency. Experimental and computational studies indicate that K acts an effective oxygen reduction reaction catalyst and can account for the dependence of performance on K weight %.

Abstract

Rechargeable lithium–air (Li–O2) batteries have drawn much interest owing to their high energy density. We report on the effect of deliberately introducing potassium impurities into the cathode material on the electrochemical performance of a Li–O2 battery. Small amounts of potassium introduced into the activated carbon (AC) cathode material in the synthesis process are found to have a dramatic effect on the performance of the Li–O2 cell. An increased amount of potassium significantly increases capacity, cycle life, and round-trip efficiency. This improved performance is probably due to a larger amount of LiO2 in the discharge product, which is a mixture of LiO2 and Li2O2, resulting from the increase in the amount of potassium present. No substantial correlation with porosity or surface area in an AC cathode is found. Experimental and computational studies indicate that potassium can act as an oxygen reduction catalyst, which can account for the dependence of performance on the amount of potassium.