A Molten Salt Lithium–Oxygen Battery

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• 作者：Vincent Giordani ; Dylan Tozier ; Hongjin Tan ; Colin M. Burke ; Betar M. Gallant ; Jasim Uddin ; Julia R. Greer ; Bryan D. McCloskey ; Gregory V. Chase ; Dan Addison
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：March 2, 2016
• 年：2016
• 卷：138
• 期：8
• 页码：2656-2663
• 全文大小：435K
• ISSN：1520-5126

文摘

Despite the promise of extremely high theoretical capacity (2Li + O₂ ↔ Li₂O₂, 1675 mAh per gram of oxygen), many challenges currently impede development of Li/O₂ battery technology. Finding suitable electrode and electrolyte materials remains the most elusive challenge to date. A radical new approach is to replace volatile, unstable and air-intolerant organic electrolytes common to prior research in the field with alkali metal nitrate molten salt electrolytes and operate the battery above the liquidus temperature (>80 °C). Here we demonstrate an intermediate temperature Li/O₂ battery using a lithium anode, a molten nitrate-based electrolyte (e.g., LiNO₃–KNO₃ eutectic) and a porous carbon O₂ cathode with high energy efficiency (∼95%) and improved rate capability because the discharge product, lithium peroxide, is stable and moderately soluble in the molten salt electrolyte. The results, supported by essential state-of-the-art electrochemical and analytical techniques such as in situ pressure and gas analyses, scanning electron microscopy, rotating disk electrode voltammetry, demonstrate that Li₂O₂ electrochemically forms and decomposes upon cycling with discharge/charge overpotentials as low as 50 mV. We show that the cycle life of such batteries is limited only by carbon reactivity and by the uncontrolled precipitation of Li₂O₂, which eventually becomes electrically disconnected from the O₂ electrode.