Simple synthesis of highly catalytic carbon-free MnCo ₂O ₄@Ni as an oxygen electrode for rechargeable Li–O ₂ batteries with long-term stability

Abstract

An effective integrated design with a free standing and carbon-free architecture of spinel MnCo ₂O ₄ oxide prepared using facile and cost effective hydrothermal method as the oxygen electrode for the Li–O ₂ battery, is introduced to avoid the parasitic reactions of carbon and binder with discharge products and reaction intermediates, respectively. The highly porous structure of the electrode allows the electrolyte and oxygen to diffuse effectively into the catalytically active sites and hence improve the cell performance. The amorphous Li ₂O ₂ will then precipitate and decompose on the surface of free-standing catalyst nanorods. Electrochemical examination demonstrates that the free-standing electrode without carbon support gives the highest specific capacity and the minimum capacity fading among the rechargeable Li–O ₂ batteries tested. The Li-O ₂ cell has demonstrated a cyclability of 119 cycles while maintaining a moderate specific capacity of 1000 mAh g ⁻¹. Furthermore, the synergistic effect of the fast kinetics of electron transport provided by the free-standing structure and the high electro-catalytic activity of the spinel oxide enables excellent performance of the oxygen electrode for Li-O ₂ cells.