Fe3O4@CoO mesospheres with core-shell nanostructure as catalyst for Li-O2 batteries

Synergized Multimetal Oxides with Amorphous/Crystalline Heterostructure as Efficient Electrocatalysts for Lithium–Oxygen Batteries

“…The CoFeCe-2 demonstrates outstanding recovery ability upon the current density increasing from 100 up to 1000 mA g −1 and then back to 100 mA g −1 . Notably, the CoFeCe-2 shows a negligible loss in the discharge/ charge capacity after cycling for 560 h upon the current density return back to 100 mA g −1 , and maintaining a stable voltage gap of ≈1.30 V. The electrochemical performance of the trimetallic CoFeCe oxide in this work and those of reported typical metal oxides [30,[35][36][37][38][39][40][41] are summarized in Figure 4f and Table S4 in the Supporting Information. The discharge capacity and cycling stability of CoFeCe-2 in this work is among the highest ones.…”

Synthesis of Non‐precious N‐doped Mesoporous Fe3O4/CoO@NC Materials towards Efficient Oxygen Reduction Reaction for Microbial Fuel Cells

“…Therefore, electrons on the CoO were partially transferred to Fe 3 O 4 because the Fe 3+ electronegativity is stronger than that of Co 2+ , which resulted in charge redistribution (i. e., the Co 2+ peaks of Fe 3 O 4 /CoO@NC were red‐shifted compared with the single CoO). The Fe 2p 3/2 spectra of Fe 3 O 4 /CoO@NC‐750 (Figure 5(f)) can be divided into two peaks at 710.5 (Fe 2+ species) and 712.9 eV (Fe 3+ species) [29, 56]. The Fe 2p 1/2 spectra showed a peak at 723.9 eV (Fe 2+ species) and 726.2 (Fe 3+ species) [51, 57].…”

“…The O 1s spectrum showed a peak at 529.3 eV, which can be assigned to the chemical bond between the transition metal atoms and oxygen atoms (M–O) [29]. The peaks at 531.5 eV can be assigned to low‐coordinated oxygen defect sites (O vacancy ) [30], whereas those at 533.1 eV can be attributed to O species that were adsorbed on the Fe 3 O 4 /CoO@NC‐750 surface (O ads ) [52].…”

“…Shang et al. [29] prepared core‐shell Fe 3 O 4 @CoO mesospheres and used them as Li−O 2 battery catalysts, which showed a low charge potential and greatly improved cycling stability. However, the poor intrinsic electronic conductivity of the metal oxides reduced their ORR performance significantly.…”

“…The high ORR activity of the CoO/hi-Mn 3 O 4 originated from the Mn III À O pair, which can act as an electron acceptor to attract electrons from CoO, and resulted in high-energy interface MnÀ OÀ Co species and high-oxidation-state CoO. Shang et al [29] prepared coreshell Fe 3 O 4 @CoO mesospheres and used them as LiÀ O 2 battery catalysts, which showed a low charge potential and greatly improved cycling stability. However, the poor intrinsic electronic conductivity of the metal oxides reduced their ORR performance significantly.…”