期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 144, 期 5, 页码 2129-2136出版社
AMER CHEMICAL SOC
DOI: 10.1021/jacs.1c10146
关键词
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资金
- National Natural Science Foundation of China [21802065]
- Shenzhen Natural Science Fund [20200925154115001]
- Shenzhen Science and Technology Program [KQTD20190929173815000]
- Guangdong Innovative and Entrepreneurial Research Team Program [2019ZT08C044]
- Guangdong-Hong Kong-Macao Joint Laboratory for PhotonicThermal-Electrical Energy Materials and Devices [2019B121205001]
- Pico and Cryo-TEM Center at SUSTech CRF
- Presidential fund and Development and Reform Commission of Shenzhen Municipality
- Cryo-EM Center of SUSTech
Utilizing electron beam irradiation, researchers in this study induced crystallization of amorphous discharge products in aprotic lithium-oxygen batteries, providing insights into the composition and distribution of discharge products. The study revealed an amorphous LiO2 phase dominating the discharge particles, with a small amount of nanocrystalline Li2O2 islands dispersed within, shedding light on the chemistry of LOBs and the importance of excluding beam-induced artifacts in traditional TEM characterizations.
Aprotic lithium-oxygen batteries (LOBs) are promising energy storage systems characterized by ultrahigh theoretical energy density. Extensive research has been devoted to this battery technology, yet the detailed operational mechanisms involved, particularly unambiguous identification of various discharge products and their specific distributions, are still unknown or are subjects of controversy. This is partly because of the intrinsic complexity of the battery chemistry but also because of the lack of atomic-level insight into the oxygen electrodes acquired via reliable techniques. In the current study, it is demonstrated that electron beam irradiation could induce crystallization of amorphous discharge products. Cryogenic conditions and a low beam dosage have to be used for reliable transmission electron microscopy (TEM) characterization. High-resolution cryo-TEM and electron energy loss spectroscopy (EELS) analysis of toroidal discharge particles unambiguously identified the discharge products as a dominating amorphous LiO2 phase with only a small amount of nanocrystalline Li2O2 islands dispersed in it. In addition, uniform mixing of carbon-containing byproducts is identified in the discharge particles with cryo-EELS, which leads to a slightly higher charging potential. The discharge products can be reversibly cycled, with no visible residue after full recharge. We believe that the amorphous superoxide dominating discharge particles can lead researchers to reconsider the chemistry of LOBs and pay special attention to exclude beam-induced artifacts in traditional TEM characterizations.
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