ja3042993_si_001.pdf (1.14 MB)
Fe/N/C Composite in Li–O2 Battery: Studies of Catalytic Structure and Activity toward Oxygen Evolution Reaction
journal contribution
posted on 2012-10-10, 00:00 authored by Jiang-Lan Shui, Naba K. Karan, Mahalingam Balasubramanian, Shu-You Li, Di-Jia LiuAtomically dispersed Fe/N/C composite was synthesized
and its role
in controlling the oxygen evolution reaction during Li–O2 battery charging was studied by use of a tetra(ethylene glycol)
dimethyl ether-based electrolyte. Li–O2 cells using
Fe/N/C as the cathode catalyst showed lower overpotentials than α-MnO2/carbon catalyst and carbon-only material. Gases evolved during
the charge step contained only oxygen for Fe/N/C cathode catalyst,
whereas CO2 was also detected in the case of α-MnO2/C or carbon-only material; this CO2 was presumably
generated from electrolyte decomposition. Our results reiterate the
catalytic effect in reducing overpotentials, which not only enhances
battery efficiency but also improves its lifespan by reducing or eliminating
electrolyte decomposition. The structure of the Fe/N/C catalyst was
characterized by transmission electron microscopy, scanning transmission
electron microscopy, inductively coupled plasma optical emission spectroscopy,
and X-ray absorption spectroscopy. Iron was found to be uniformly
distributed within the carbon matrix, and on average, Fe was coordinated
by 3.3 ± 0.6 and 2.2 ± 0.3 low Z elements (C/N/O) at bond
distances of ∼1.92 and ∼2.09 Å, respectively.