Bae, Youngjoon Song, Hyelynn Park, Hyeokjun Lim, Hee-Dae Kwon, Hyuk Jae Ko, Youngmin Huynh, Chi Ovalle-Robles, Raquel Kim, Yong Hyup Im, Dongmin Kang, Kisuk 2024-01-19T16:31:06Z 2024-01-19T16:31:06Z 2021-09-02 2020-10-27 1614-6832 https://pubs.kist.re.kr/handle/201004/117978 Low round-trip efficiency and poor cycle stability remain the major challenges associated with lithium-oxygen (Li-O-2) batteries. These issues are primarily triggered by or correlated to the radical species produced during the operation of Li-O(2)cells, which lead to significant deterioration of the electrolytes and air electrodes. Regulation of the reactivity of these radical species would thus open up opportunities to suppress such side reactions. Herein, a dual-functioning molecule that is capable of mitigating the reactivity of radical species produced in a Li-O(2)cell by reversibly forming stable intermediate complex during both the discharge and charge processes is introduced. Specifically, 5,5-dimethyl-1-pyrroline N-oxide (DMPO) is exploited, which has been widely used as a chemical agent to detect oxygen radicals, to induce the reversible formation of an intermediate complex, DMPO-O-2(-), in the presence of superoxide radicals. It is demonstrated that DMPO mediates the O-2(-)-involved electrochemical reaction, leading to significant suppression of side reactions and a remarkably improved oxygen efficiency. Unexpectedly, it is also observed that upon charging, DMPO actively scavenges the superoxides from the surface of discharge products, thus substantially lowering the charging overpotential. The combined radical mediation and scavenging of superoxides result in cycle stability of a practical Li-O(2)cell over 200 cycles with a specific capacity of 1000 mAh g(-1). The findings indicate the importance of controlling the reactivity of radical species and suggest a new pathway toward the realization of stable and efficient Li-O(2)batteries. English WILEY-V C H VERLAG GMBH LI-O-2 BATTERIES SOLVENT STABILITY APROTIC-SOLVENTS LI2O2 REDUCTION CATALYST CARBON RECHARGEABILITY ELECTRODE SHUTTLE Dual-Functioning Molecular Carrier of Superoxide Radicals for Stable and Efficient Lithium-Oxygen Batteries Article 10.1002/aenm.201904187 1 ADVANCED ENERGY MATERIALS, v.10, no.40 ADVANCED ENERGY MATERIALS 10 40 scie scopus 000571766300001 2-s2.0-85091279515 Chemistry, Physical Energy & Fuels Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Energy & Fuels Materials Science Physics Article LI-O-2 BATTERIES SOLVENT STABILITY APROTIC-SOLVENTS LI2O2 REDUCTION CATALYST CARBON RECHARGEABILITY ELECTRODE SHUTTLE electron paramagnetic resonance in situ differential electrochemical mass spectroscopy lithium-oxygen batteries stability superoxide