Lithium-oxygen (Li-O2) batteries have an ultra-high theoretical specific energy (~5200 Wh/kg when the weights of Li and oxygen are included) and are expected to have a practical specific energy of around 800 Wh/kg that is about 3 to 4 times of those of the state-of-the-art Li-ion batteries (ca. 200~250 Wh/kg). However, the development of rechargeable Li-O2 batteries faces significant challenges including the decomposition of electrolyte, large over-voltage during charge process, instability of conventional carbon-based oxygen electrode materials, and protection of Li metal anode. It is well known that highly reactive reduced oxygen species (O2-●, LiO2, O22-, and Li2O2) are generated on the oxygen electrode surface during the discharge of a Li-O2 battery. These reduced oxygen species attack every component in the Li-O2 batteries and significantly limit the reversibility and the cycle life of the rechargeable Li-O2 batteries. Therefore, the chemical and electrochemical stability of all the components in a Li-O2 battery, especially the electrolyte, oxygen electrode material (typically carbon-based) and Li metal anode, need to be carefully investigated and developed in an oxygen-rich environment. Recently, we have used several approaches to enhance the cycling stability of rechargeable Li-O2 batteries by employing highly concentrated electrolytes, pretreatment of the carbon-based electrodes and Li metal anodes, catalysts, and non-carbon-based materials as oxygen electrodes. The effects of these methods on the stabilities of oxygen electrodes and Li metal anodes as well as the performances of Li-O2 batteries were systematically investigated. Details of the investigations will be reported and discussed in the presentation.

Development of stable rechargeable lithium-oxygen batteries

254th National Meeting (2017)

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