3D Foam-Like Composites of MoC Nanorods Coated by N-Doped Carbon: A Novel Self-Standing and Binder-Free O Electrode for Li-O Batteries.

The development of self-standing and binder-free O electrodes is significant for enhancing the total specific energy density and suppressing parasitic reactions for Li-O batteries, which is still a formidable challenge thus far. Here, a three-dimensional foam-like composite composed of MoC nanorods decorated by different amounts of N-doped carbon (MoC-NR@xNC (x = 5, 11, and 16 wt %)) was directly employed as the O electrode without applications of any binders and current collectors. MoC-NR@xNC presents a network microstructure with interconnected macropore and mesoporous channels, which is beneficial to achieving fast Li migration and O diffusion, facilitating the electrolyte impregnation, and providing enough space for LiO storage. Additionally, the coated N-doped carbon layer can largely improve the electrochemical stability and conductivity of MoC. The cell with MoC-NR@11NC shows a considerable cyclability of 200 cycles with an overpotential of 0.28 V in the first cycle at a constant current density of 100 mA g, a superior reversibility associated with the formation and decomposition of LiO as desired, and a high electrochemical stability. On the basis of the experimental results, the electrochemical mechanism for the cell using MoC-NR@11NC is proposed. These results represent a promising process in the development of a self-standing and binder-free foam-based electrode for Li-O batteries.