The Use of Spray-Dried Mn₃O₄/C Composites as Electrocatalysts for Li-O₂ Batteries.
The electrocatalytic activities of Mn₃O₄/C composites are studied in lithium-oxygen (Li-O₂) batteries as cathode catalysts. The Mn₃O₄/C composites are fabricated using ultrasonic spray pyrolysis (USP) with organic surfactants as the carbon sources. The physical and electrochemical performance of the composites is characterized by X-ray diffraction, scanning electron microscopy, particle size analysis, Brunauer-Emmett-Teller (BET) measurements, elemental analysis, galvanostatic charge-discharge methods and rotating ring-disk electrode (RRDE) measurements. The electrochemical tests demonstrate that the Mn₃O₄/C composite that is prepared using Trition X-114 (TX114) surfactant has higher activity as a bi-functional catalyst and delivers better oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalytic performance in Li-O₂ batteries because there is a larger surface area and particles are homogeneous with a meso/macro porous structure. The rate constant (kf) for the production of superoxide radical (O₂•-) and the propylene carbonate (PC)-electrolyte decomposition rate constant (k) for M₃O₄/C and Super P electrodes are measured using RRDE experiments and analysis in the 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF₆)/PC electrolyte. The results show that TX114 has higher electrocatalytic activity for the first step of ORR to generate O₂•-and produces a faster PC-electrolyte decomposition rate.
Department of Applied Chemistry, National University of Kaohsiung, Kaohsiung City 81148, Taiwan. hong-kai84@hotmail.com.
Hong-Kai
HK
Yang
Department of Applied Chemistry, National University of Kaohsiung, Kaohsiung City 81148, Taiwan. ccchin17@gmail.com.
Chih-Chun
CC
Chin
Department of Applied Chemistry, National University of Kaohsiung, Kaohsiung City 81148, Taiwan. jschen@nuk.edu.tw.
Jenn-Shing
JS
Chen
Mn3O4/C; cathode; lithium-oxygen battery; rotating ring-disk electrode