title: Polyimide-coated carbon electrodes combined with redox mediators for superior Li-O2cells with excellent cycling performance and decreased overpotential.
abstract: We report an air electrode employing polyimide-coated carbon nanotubes (CNTs) combined with a redox mediator for Li-O2cells with enhanced electrochemical performance. The polyimide coating on the carbon surface suppresses unwanted side reactions, which decreases the amount of accumulated reaction products on the surface of the air electrode during cycling. The redox mediators lower the overpotential of the Li-O2cells because they can easily transfer electrons from the electrode to the reaction products. The low overpotential can also decrease the side reactions that activate at a high potential range. Specifically, the CsI redox mediator effectively interrupted dendrite growth on the Li anode during cycling due to the shielding effect of its Cs+ions and acted as a redox mediator due to its I-ions. LiNO3also facilitates the decrease in side reactions and the stabilization of the Li anode. The synergic effect of the polyimide coating and the electrolyte containing the LiNO3/CsI redox mediator leads to a low overpotential and excellent cycling performance (over 250 cycles with a capacity of 1,500 mAh·gelectrode-1).
authors.affiliation: Department of Advanced Materials Engineering, Kyonggi University, 154-42 Gwanggyosan-ro, Yeongtong-gu, Suwon-si, Gyeonggi-Do, 443-760, Korea.
authors.forename: Seon Hye
authors.initials: SH
authors.lastname: Yoon
authors.affiliation: Department of Advanced Materials Engineering, Kyonggi University, 154-42 Gwanggyosan-ro, Yeongtong-gu, Suwon-si, Gyeonggi-Do, 443-760, Korea.
authors.forename: Yong Joon
authors.initials: YJ
authors.lastname: Park