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The Effect of Potassium Impurities Deliberately Introduced into Activated Carbon Cathodes on the Performance of Lithium–Oxygen Batteries
Author(s) -
Zhai Dengyun,
Lau Kah Chun,
Wang HsienHau,
Wen Jianguo,
Miller Dean J.,
Kang Feiyu,
Li Baohua,
Zavadil Kevin,
Curtiss Larry A.
Publication year - 2015
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201500960
Subject(s) - lithium (medication) , impurity , oxygen , potassium , carbon fibers , cathode , activated carbon , inorganic chemistry , chemistry , materials science , organic chemistry , adsorption , medicine , composite number , composite material , endocrinology
Rechargeable lithium–air (Li–O 2 ) 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–O 2 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–O 2 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 LiO 2 in the discharge product, which is a mixture of LiO 2 and Li 2 O 2 , 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.