Perovskite Oxide La_0.8Sr_0.2MnO₃ As A Electrocatalyst For Air Electrode Of Lithium–air Batteries

Oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) are the most important electrochemical reactions on gas diffusion electrode of lithium–air batteries. The air electrode, especially efficient electrocatalyst for both ORR and OER is crucial. In this paper, perovskite oxide La0.8Sr0.2Mn O3(LSM) is studied as a electrocatalyst for air electrode of lithium-air batteries. A hollow spherical LSM perovskite oxide has been prepared using a new carbonate-template route, The catalytic activity of the oxide for the ORR in alkaline solution has been studied through a rotating ring-disk electrode. The results show that hollow spherical LSM is more active than commercial LSM and urchin-like LSM and is comparable to the activity of Pt/C. We present LSM perovskite nanorods as high active electrocatalyst fabricated via a soft template method for lithium–air batteries.The as–prepared LSM nanorods are microporous with numerous defects. Lithium–air batteries based on the microporous LSM nanorods electrocatalysts show enhanced electrochemical performances, including high first discharge specific capacity(6890 m Ah g–1 at 200 m A g–1), low overpotential, good rate capability, and cycle stability(only 1.1% voltage loss after 30 circles of specific capacity limit of 1000 m Ah g–1 tested at 200 m A g–1). The improved performance might be due to the synergistic effect of the unique microporous and one–dimensional structure and numerous defects of the prepared LSM catalyst. Because LSM has low intrinsic activity for OER, so we coat Ni Co2O4 film on the surface of microporous LSM nanorods by mpregnation method. In 0.1 M KOH solution, the OER catalytic activity of LSM nanorods coated with Ni Co2O4 film is more active than microporous LSM nanorods. Lithium–air batteries based on the LSM nanorods coated with Ni Co2O4 film electrocatalysts show ameliorative rate capability, round–trip efficiency and cycle stability.