Functionalizing the Surface of Lithium-Metal Anodes

• Published in: ChemPlusChem (Weinheim, Germany) Vol. 80; no. 2; pp. 363 - 367
• Main Authors: Buonaiuto, Megan, Neuhold, Susanna, Schroeder, David J., Lopez, Carmen M., Vaughey, John T.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01-02-2015; WILEY‐VCH Verlag
• Subjects: electrochemistry; lithium; polymers; silanes; surface chemistry
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.201402084

Metal–air batteries are one important aspect of many in moving beyond lithium‐ion research efforts. However, as our understanding of how molecular oxygen can act as a rechargeable cathode has progressed, the problems associated with how these materials at various states of charge interact with the lithium‐metal anode are only beginning to come to the surface. In this study we have devised a method to coat the surface of lithium with a functional group to act as either an anchor for further derivation studies or be polymerized to create a nanometer‐thick polymer coating attached to the surface by silane groups. These stable films, formed by polymerization of vinyl substituents, lower cell impedance at the electrode and over the first 50 cycles, increase cycling efficiency, and demonstrate lower‐capacity fade.
Interfacing: Stabilizing the surface of lithium metal is an important challenge that must be overcome to enable lithium–air or lithium–sulfur batteries to succeed. Controlling the interface between the electrolyte and lithium is thus critical. By attaching vinyl‐containing silanes to the hydroxy‐terminated surface of lithium metal, a critical functional group is introduced at this interface that can be used to tailor this critical interaction (see figure; scale bars: 500 μm).