Ag modified Ni x Al y Mn z O 2 polynary metal oxides (Ag@ NAM ) synthesized by a facile precipitation method as bifunctional catalyst for high performance air electrode of lithium‐oxygen batteries

Abstract

An ideal catalyst material in the air electrode can reduce the over-potentials and obtain an excellent electrochemical performance for lithium-oxygen batteries. In this paper, Ag modified NixAlyMnzO2 polynary metal oxides (Ag@NAM) is synthesized by a facile precipitation method and as a bifunctional catalyst for high performance air electrode of lithium-oxygen batteries. X-ray diffraction and Raman spectrum test results show that the Ag@NAM catalyst has high crystallinity, which can prevent the lattice distortion caused by manganese dissolution and Ag staying on the surface can change the bond energy in order to supply some special catalytic effects. Through scanning electron microscope observation, Ag@NAM with the proportion of Ag and NixAlyMnzO2 polynary metal oxides to 8.5:1.5 has regular block morphology and uniform grain size. When an air electrode catalyst for lithium-oxygen batteries, Ag@NAM can provide a large electrochemical reaction space along with enough oxygen atoms and lithium ions for electrocatalytic and electrochemical reactions. Specific discharge capacities can achieve to 6834.83, 6477.07, and 4357.14 mAh g−1 at 0.1, 0.2, and 0.3 mA cm−2 current densities, respectively. In addition, this air electrode can carry out stable 28-time charge and discharge cycles. Hence, we feel that Ag@NAM catalyst can play an ideal bifunctional catalytic role and effectively reduce the polarization resistance.