A non-precious metal bifunctional oxygen electrode for alkaline anion exchange membrane cells

An initial study of a non-precious metal based bifunctional oxygen electrode for use in regenerative fuel cells with alkaline anion exchange membranes is described. Four nanometer size CuxMn0.9−xCo2.1O4 samples (x = 0, 0.3, 0.6, and 0.9) were prepared and characterized with XRD, SEM, TEM, and cyclic voltammetry. The CuxMn0.9−xCo2.1O4 samples exhibited promising ORR and OER catalytic activities. The gap between ORR half wave potentials of Pt/C and CuxMn0.9−xCo2.1O4 in 1 M KOH achieved only 50 mV. The onset potentials for OER on CuxMn0.9−xCo2.1O4 catalysts were more than 100 mV more negative than Pt/C in 1 M KOH. MEA with CuxMn0.9−xCo2.1O4 bifunctional oxygen electrode was prepared with CCM method and applied in a laboratory scale regenerative fuel cell. In fuel cell mode the peak power density was over 80 mW cm−2 and in electrolyser mode the onset voltage was about 1.55 V. The fuel cell to electrolyser voltage ration at 100 mA cm−2 achieved c.a. 31.87%.

► Nanopowder of CuxMn0.9−xCo2.1O4 was prepared with a novel method.
► CuxMn0.9−xCo2.1O4 exhibited promising catalytic activities for both OER and ORR.
► An AAEM regenerative fuel cell with CuxMn0.9−xCo2.1O4 electrode was realized.
► It exhibited fine polarization performances in fuel cell mode and electrolyser mode.
► MEA resistance shall be reduced in subsequent developments.