Title

Reversibility of Noble Metal-Catalyzed Aprotic Li-O₂ Batteries

Authors

Shunchao Ma, State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
Yang Wu, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University , Beijing 100084, P. R. China.
Jiawei Wang, State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
Yelong Zhang, State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
Yantao Zhang, State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
Xinxiu Yan, State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.
Yang Wei, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University , Beijing 100084, P. R. China.
Peng Liu, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University , Beijing 100084, P. R. China.
Jiaping Wang, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University , Beijing 100084, P. R. China.
Kaili Jiang, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University , Beijing 100084, P. R. China.
Shoushan Fan, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University , Beijing 100084, P. R. China.
Ye Xu, Department of Chemical Engineering, Louisiana State University , Baton Rouge, Louisiana 70803, United States.
Zhangquan Peng, State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022, P. R. China.

Document Type

Article

Publication Date

12-9-2015

Abstract

The aprotic Li-O2 battery has attracted a great deal of interest because, theoretically, it can store far more energy than today's batteries. Toward unlocking the energy capabilities of this neotype energy storage system, noble metal-catalyzed high surface area carbon materials have been widely used as the O2 cathodes, and some of them exhibit excellent electrochemical performances in terms of round-trip efficiency and cycle life. However, whether these outstanding electrochemical performances are backed by the reversible formation/decomposition of Li2O2, i.e., the desired Li-O2 electrochemistry, remains unclear due to a lack of quantitative assays for the Li-O2 cells. Here, noble metal (Ru and Pd)-catalyzed carbon nanotube (CNT) fabrics, prepared by magnetron sputtering, have been used as the O2 cathode in aprotic Li-O2 batteries. The catalyzed Li-O2 cells exhibited considerably high round-trip efficiency and prolonged cycle life, which could match or even surpass some of the best literature results. However, a combined analysis using differential electrochemical mass spectrometry and Fourier transform infrared spectroscopy, revealed that these catalyzed Li-O2 cells (particularly those based on Pd-CNT cathodes) did not work according to the desired Li-O2 electrochemistry. Instead the presence of noble metal catalysts impaired the cells' reversibility, as evidenced by the decreased O2 recovery efficiency (the ratio of the amount of O2 evolved during recharge/that consumed in the preceding discharge) coupled with increased CO2 evolution during charging. The results reported here provide new insights into the O2 electrochemistry in the aprotic Li-O2 batteries containing noble metal catalysts and exemplified the importance of the quantitative assays for the Li-O2 reactions in the course of pursuing truly rechargeable Li-O2 batteries.

Publication Source (Journal or Book title)

Nano letters

First Page

8084

Last Page

90

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