Influence of Hydrocarbon and CO2 on the Reversibility of Li鈥揙2 Chemistry Using In Situ Ambient Pressure X-ray Photoelectron Spectroscopy

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• 作者：Yi-Chun Lu ; Ethan J. Crumlin ; Thomas J. Carney ; Lo茂c Baggetto ; Gabriel M. Veith ; Nancy J. Dudney ; Zhi Liu ; Yang Shao-Horn
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 12, 2013
• 年：2013
• 卷：117
• 期：49
• 页码：25948-25954
• 全文大小：339K
• 年卷期：v.117,no.49(December 12, 2013)
• ISSN：1932-7455

文摘

Identifying fundamental barriers that hinder reversible lithium鈥搊xygen (Li鈥揙₂) redox reaction is essential for developing efficient and long-lasting rechargeable Li鈥揙₂ batteries. Addressing these challenges is being limited by parasitic reactions in the carbon-based O₂鈥揺lectrode with aprotic electrolytes. Understanding the mechanisms of these parasitic reactions is hampered by the complexity that multiple and coupled parasitic reactions involving carbon, electrolytes, and Li鈥揙₂ reaction intermediates/products can occur simultaneously. In this work, we employed solid-state cells free of carbon and aprotic electrolytes to probe the influence of surface adventitious hydrocarbons and carbon dioxide (CO₂) on the reversibility of the Li鈥揙₂ redox chemistry using in situ synchrotron-based ambient pressure X-ray photoelectron spectroscopy. Direct evidence was provided, for the first time, that surface hydrocarbons and CO₂ irreversibly react with Li鈥揙₂ reaction intermediates/products such as Li₂O₂ and Li₂O, forming carboxylate and carbonate-based species, which cannot be removed fully upon recharge. The slower Li₂O₂ oxidation kinetics was correlated with increasing coverage of surface carbonate/carboxylate species. Our work critically points out that materials design that mitigates the reactivity between Li鈥揙₂ reaction products and common impurities in the atmosphere is needed to achieve long cycle-life Li鈥揙₂ batteries.