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Advanced Materials for Energy Storage Lab.

Journal Articles

2020 Anchored mediator enabling shuttle–free redox mediation in lithium–oxygen batteries

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작성자 AMESL 작성일 24-09-02 16:24

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Author
Youngmin Ko, Hyunji Park, Kyunam Lee, Sung Joo Kim, Hyeokjun Park, Youngjoon Bae, Jihyeon Kim, Soo Young Park, Ji Eon Kwon, Kisuk Kang*
Journal
Angewandte Chemie International Edition
Vol
59 (13)
Page
5376-5380
Year
2020

Redox mediators (RMs) are considered an effective countermeasure to reduce the large polarization in lithium-oxygen batteries. Nevertheless, achieving sufficient enhancement of the cyclability is limited by the trade-offs of freely mobile RMs, which are beneficial for charge transport but also trigger the shuttling phenomenon. Here, we successfully decoupled the charge-carrying redox property of RMs and shuttling phenomenon by anchoring the RMs in polymer form, where physical RM migration was replaced by charge transfer along polymer chains. Using PTMA (poly(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl methacrylate)) as a polymer model system based on the well-known RM tetramethylpiperidinyloxyl (TEMPO), it is demonstrated that PTMA can function as stationary RM, preserving the redox activity of TEMPO. The efficiency of RM-mediated Li2O2 decomposition remains remarkably stable without the consumption of oxidized RMs or degradation of the lithium anode, resulting in an improved performance of the lithium-oxygen cell.