The Use of Spray-Dried Mn(3)O(4)/C Composites as Electrocatalysts for Li–O(2) Batteries

The electrocatalytic activities of Mn(3)O(4)/C composites are studied in lithium–oxygen (Li–O(2)) batteries as cathode catalysts. The Mn(3)O(4)/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 Mn(3)O(4)/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–O(2) batteries because there is a larger surface area and particles are homogeneous with a meso/macro porous structure. The rate constant (k(f)) for the production of superoxide radical (O(2)(•)(−)) and the propylene carbonate (PC)-electrolyte decomposition rate constant (k) for M(3)O(4)/C and Super P electrodes are measured using RRDE experiments and analysis in the 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF(6))/PC electrolyte. The results show that TX114 has higher electrocatalytic activity for the first step of ORR to generate O(2)(•)(−) and produces a faster PC-electrolyte decomposition rate.